1
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Zintel TM, Pizzollo J, Claypool CG, Babbitt CC. Astrocytes Drive Divergent Metabolic Gene Expression in Humans and Chimpanzees. Genome Biol Evol 2024; 16:evad239. [PMID: 38159045 PMCID: PMC10829071 DOI: 10.1093/gbe/evad239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 11/13/2023] [Accepted: 12/23/2023] [Indexed: 01/03/2024] Open
Abstract
The human brain utilizes ∼20% of all of the body's metabolic resources, while chimpanzee brains use <10%. Although previous work shows significant differences in metabolic gene expression between the brains of primates, we have yet to fully resolve the contribution of distinct brain cell types. To investigate cell type-specific interspecies differences in brain gene expression, we conducted RNA-seq on neural progenitor cells, neurons, and astrocytes generated from induced pluripotent stem cells from humans and chimpanzees. Interspecies differential expression analyses revealed that twice as many genes exhibit differential expression in astrocytes (12.2% of all genes expressed) than neurons (5.8%). Pathway enrichment analyses determined that astrocytes, rather than neurons, diverged in expression of glucose and lactate transmembrane transport, as well as pyruvate processing and oxidative phosphorylation. These findings suggest that astrocytes may have contributed significantly to the evolution of greater brain glucose metabolism with proximity to humans.
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Affiliation(s)
- Trisha M Zintel
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA, USA
| | - Jason Pizzollo
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA, USA
| | - Christopher G Claypool
- Organismic and Evolutionary Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA, USA
| | - Courtney C Babbitt
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA, USA
- Organismic and Evolutionary Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA, USA
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2
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Hao Y, Song G, Zhang YE, Zhai W, Jia C, Ji Y, Tang S, Lv H, Qu Y, Lei F. Divergent contributions of coding and noncoding sequences to initial high-altitude adaptation in passerine birds endemic to the Qinghai-Tibet Plateau. Mol Ecol 2023; 32:3524-3540. [PMID: 37000417 DOI: 10.1111/mec.16942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 02/27/2023] [Accepted: 03/27/2023] [Indexed: 04/01/2023]
Abstract
Early events in the evolution of an ancestral lineage can shape the adaptive patterns of descendant species, but the evolutionary mechanisms driving initial adaptation from an ancestor remain largely unexplored. High-altitude adaptations have been extensively explored from the viewpoint of protein-coding genes; however, the contribution of noncoding regions remains relatively neglected. Here, we integrate genomic and transcriptomic data to investigate adaptive evolution in the ancestor of three high-altitude snowfinch species endemic to the Qinghai-Tibet Plateau. Our genome-wide scan for adaptation in the snowfinch ancestor identifies strong adaptation signals in functions of development and metabolism for the coding genes, but in functions of the nervous system development for noncoding regions. This pattern is exclusive to the snowfinch ancestor compared to a control ancestral lineage subject to weak selection. Changes in noncoding regions in the snowfinch ancestor, especially those nearest to coding genes, may be disproportionately associated with the differential expression of genes in the brain tissue compared to other tissues. Extensive gene expression in the brain tissue can be further altered via genetic regulatory networks of transcription factors harbouring potential accelerated regulatory regions (e.g., the development-related transcription factor YEATS4). Altogether, our study provides new evidence concerning how coding and noncoding sequences work through decoupled pathways in initial adaptation to the selective pressure of high-altitude environments. The analysis highlights the idea that noncoding sequences may be promising elements in facilitating the rapid evolution and adaptation to high altitudes.
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Affiliation(s)
- Yan Hao
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Gang Song
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Yong E Zhang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing, China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, China
| | - Weiwei Zhai
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, China
| | - Chenxi Jia
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Yanzhu Ji
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Shiyu Tang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Hongrui Lv
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Yanhua Qu
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Fumin Lei
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing, China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, China
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3
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Alachkar N, Norton D, Wolkensdorfer Z, Muldoon M, Paszek P. Variability of the innate immune response is globally constrained by transcriptional bursting. Front Mol Biosci 2023; 10:1176107. [PMID: 37441161 PMCID: PMC10333517 DOI: 10.3389/fmolb.2023.1176107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 06/15/2023] [Indexed: 07/15/2023] Open
Abstract
Transcription of almost all mammalian genes occurs in stochastic bursts, however the fundamental control mechanisms that allow appropriate single-cell responses remain unresolved. Here we utilise single cell genomics data and stochastic models of transcription to perform global analysis of the toll-like receptor (TLR)-induced gene expression variability. Based on analysis of more than 2000 TLR-response genes across multiple experimental conditions we demonstrate that the single-cell, gene-by-gene expression variability can be empirically described by a linear function of the population mean. We show that response heterogeneity of individual genes can be characterised by the slope of the mean-variance line, which captures how cells respond to stimulus and provides insight into evolutionary differences between species. We further demonstrate that linear relationships theoretically determine the underlying transcriptional bursting kinetics, revealing different regulatory modes of TLR response heterogeneity. Stochastic modelling of temporal scRNA-seq count distributions demonstrates that increased response variability is associated with larger and more frequent transcriptional bursts, which emerge via increased complexity of transcriptional regulatory networks between genes and different species. Overall, we provide a methodology relying on inference of empirical mean-variance relationships from single cell data and new insights into control of innate immune response variability.
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Affiliation(s)
- Nissrin Alachkar
- Division of Immunology, Immunity to Infection and Respiratory Medicine, Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Dale Norton
- Division of Immunology, Immunity to Infection and Respiratory Medicine, Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Zsofia Wolkensdorfer
- Division of Immunology, Immunity to Infection and Respiratory Medicine, Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Mark Muldoon
- Department of Mathematics, University of Manchester, Manchester, United Kingdom
| | - Pawel Paszek
- Division of Immunology, Immunity to Infection and Respiratory Medicine, Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
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4
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Fair T, Pollen AA. Genetic architecture of human brain evolution. Curr Opin Neurobiol 2023; 80:102710. [PMID: 37003107 DOI: 10.1016/j.conb.2023.102710] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 02/20/2023] [Accepted: 02/26/2023] [Indexed: 04/03/2023]
Abstract
Comparative studies of hominids have long sought to identify mutational events that shaped the evolution of the human nervous system. However, functional genetic differences are outnumbered by millions of nearly neutral mutations, and the developmental mechanisms underlying human nervous system specializations are difficult to model and incompletely understood. Candidate-gene studies have attempted to map select human-specific genetic differences to neurodevelopmental functions, but it remains unclear how to contextualize the relative effects of genes that are investigated independently. Considering these limitations, we discuss scalable approaches for probing the functional contributions of human-specific genetic differences. We propose that a systems-level view will enable a more quantitative and integrative understanding of the genetic, molecular and cellular underpinnings of human nervous system evolution.
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Affiliation(s)
- Tyler Fair
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA; Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA. https://twitter.com/@TylerFair_
| | - Alex A Pollen
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.
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5
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Ji X, Cai J, Liang L, Shi T, Liu J. Gene expression variability across cells and species shapes the relationship between renal resident macrophages and infiltrated macrophages. BMC Bioinformatics 2023; 24:72. [PMID: 36858955 PMCID: PMC9976410 DOI: 10.1186/s12859-023-05198-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 02/21/2023] [Indexed: 03/03/2023] Open
Abstract
BACKGROUND Two main subclasses of macrophages are found in almost all solid tissues: embryo-derived resident tissue macrophages and bone marrow-derived infiltrated macrophages. These macrophage subtypes show transcriptional and functional divergence, and the programs that have shaped the evolution of renal macrophages and related signaling pathways remain poorly understood. To clarify these processes, we performed data analysis based on single-cell transcriptional profiling of renal tissue-resident and infiltrated macrophages in human, mouse and rat. RESULTS In this study, we (i) characterized the transcriptional divergence among species and (ii) illustrated variability in expression among cells of each subtype and (iii) compared the gene regulation network and (iv) ligand-receptor pairs in human and mouse. Using single-cell transcriptomics, we mapped the promoter architecture during homeostasis. CONCLUSIONS Transcriptionally divergent genes, such as the differentially TF-encoding genes expressed in resident and infiltrated macrophages across the three species, vary among cells and include distinct promoter structures. The gene regulatory network in infiltrated macrophages shows comparatively better species-wide consistency than resident macrophages. The conserved transcriptional gene regulatory network in infiltrated macrophages among species is uniquely enriched in pathways related to kinases, and TFs associated with largely conserved regulons among species are uniquely enriched in kinase-related pathways.
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Affiliation(s)
- Xiangjun Ji
- grid.284723.80000 0000 8877 7471Guangdong Provincial Key Laboratory of Proteomics, Department of Pathophysiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515 China
| | - Junwei Cai
- grid.284723.80000 0000 8877 7471Guangdong Provincial Key Laboratory of Proteomics, Department of Pathophysiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515 China
| | - Lixin Liang
- grid.284723.80000 0000 8877 7471Guangdong Provincial Key Laboratory of Proteomics, Department of Pathophysiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515 China
| | - Tieliu Shi
- Center for Bioinformatics and Computational Biology, The Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, China. .,Beijing Advanced Innovation Center, for Big Data-Based Precision Medicine, Beihang University and Capital Medical University, Beijing, 100083, China.
| | - Jinghua Liu
- Guangdong Provincial Key Laboratory of Proteomics, Department of Pathophysiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China.
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Levchenko A, Gusev F, Rogaev E. The evolutionary origin of psychosis. Front Psychiatry 2023; 14:1115929. [PMID: 36741116 PMCID: PMC9894884 DOI: 10.3389/fpsyt.2023.1115929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 01/05/2023] [Indexed: 01/21/2023] Open
Abstract
Imagination, the driving force of creativity, and primary psychosis are human-specific, since we do not observe behaviors in other species that would convincingly suggest they possess the same traits. Both these traits have been linked to the function of the prefrontal cortex, which is the most evolutionarily novel region of the human brain. A number of evolutionarily novel genetic and epigenetic changes that determine the human brain-specific structure and function have been discovered in recent years. Among them are genomic loci subjected to increased rates of single nucleotide substitutions in humans, called human accelerated regions. These mostly regulatory regions are involved in brain development and sometimes contain genetic variants that confer a risk for schizophrenia. On the other hand, neuroimaging data suggest that mind wandering and related phenomena (as a proxy of imagination) are in many ways similar to rapid eye movement dreaming, a function also present in non-human species. Furthermore, both functions are similar to psychosis in several ways: for example, the same brain areas are activated both in dreams and visual hallucinations. In the present Perspective we hypothesize that imagination is an evolutionary adaptation of dreaming, while primary psychosis results from deficient control by higher-order brain areas over imagination. In the light of this, human accelerated regions might be one of the key drivers in evolution of human imagination and the pathogenesis of psychotic disorders.
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Affiliation(s)
- Anastasia Levchenko
- Institute of Translational Biomedicine, Saint Petersburg State University, Saint Petersburg, Russia
| | - Fedor Gusev
- Center for Genetics and Life Sciences, Department of Genetics, Sirius University of Science and Technology, Sochi, Russia.,Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Evgeny Rogaev
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia.,Department of Psychiatry, UMass Chan Medical School, Shrewsbury, MA, United States
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7
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Dutrow EV, Serpell JA, Ostrander EA. Domestic dog lineages reveal genetic drivers of behavioral diversification. Cell 2022; 185:4737-4755.e18. [PMID: 36493753 PMCID: PMC10478034 DOI: 10.1016/j.cell.2022.11.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 09/06/2022] [Accepted: 10/31/2022] [Indexed: 12/13/2022]
Abstract
Selective breeding of domestic dogs has generated diverse breeds often optimized for performing specialized tasks. Despite the heritability of breed-typical behavioral traits, identification of causal loci has proven challenging due to the complexity of canine population structure. We overcome longstanding difficulties in identifying genetic drivers of canine behavior by developing a framework for understanding relationships between breeds and the behaviors that define them, utilizing genetic data for over 4,000 domestic, semi-feral, and wild canids and behavioral survey data for over 46,000 dogs. We identify ten major canine genetic lineages and their behavioral correlates and show that breed diversification is predominantly driven by non-coding regulatory variation. We determine that lineage-associated genes converge in neurodevelopmental co-expression networks, identifying a sheepdog-associated enrichment for interrelated axon guidance functions. This work presents a scaffold for canine diversification that positions the domestic dog as an unparalleled system for revealing the genetic origins of behavioral diversity.
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Affiliation(s)
- Emily V Dutrow
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - James A Serpell
- Department of Clinical Sciences and Advanced Medicine, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104, USA
| | - Elaine A Ostrander
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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8
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Abstract
Human accelerated regions (HARs) are the fastest-evolving sequences in the human genome. When HARs were discovered in 2006, their function was mysterious due to scant annotation of the noncoding genome. Diverse technologies, from transgenic animals to machine learning, have consistently shown that HARs function as gene regulatory enhancers with significant enrichment in neurodevelopment. It is now possible to quantitatively measure the enhancer activity of thousands of HARs in parallel and model how each nucleotide contributes to gene expression. These strategies have revealed that many human HAR sequences function differently than their chimpanzee orthologs, though individual nucleotide changes in the same HAR may have opposite effects, consistent with compensatory substitutions. To fully evaluate the role of HARs in human evolution, it will be necessary to experimentally and computationally dissect them across more cell types and developmental stages.
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Affiliation(s)
- Sean Whalen
- Gladstone Institute of Data Science and Biotechnology, San Francisco, California, USA; ,
| | - Katherine S Pollard
- Gladstone Institute of Data Science and Biotechnology, San Francisco, California, USA; ,
- Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
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9
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Zug R, Uller T. Evolution and dysfunction of human cognitive and social traits: A transcriptional regulation perspective. EVOLUTIONARY HUMAN SCIENCES 2022; 4:e43. [PMID: 37588924 PMCID: PMC10426018 DOI: 10.1017/ehs.2022.42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 08/11/2022] [Accepted: 09/11/2022] [Indexed: 11/07/2022] Open
Abstract
Evolutionary changes in brain and craniofacial development have endowed humans with unique cognitive and social skills, but also predisposed us to debilitating disorders in which these traits are disrupted. What are the developmental genetic underpinnings that connect the adaptive evolution of our cognition and sociality with the persistence of mental disorders with severe negative fitness effects? We argue that loss of function of genes involved in transcriptional regulation represents a crucial link between the evolution and dysfunction of human cognitive and social traits. The argument is based on the haploinsufficiency of many transcriptional regulator genes, which makes them particularly sensitive to loss-of-function mutations. We discuss how human brain and craniofacial traits evolved through partial loss of function (i.e. reduced expression) of these genes, a perspective compatible with the idea of human self-domestication. Moreover, we explain why selection against loss-of-function variants supports the view that mutation-selection-drift, rather than balancing selection, underlies the persistence of psychiatric disorders. Finally, we discuss testable predictions.
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Affiliation(s)
- Roman Zug
- Department of Biology, Lund University, Lund, Sweden
| | - Tobias Uller
- Department of Biology, Lund University, Lund, Sweden
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10
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Pizzollo J, Zintel TM, Babbitt CC. Differentially active and conserved neural enhancers define two forms of adaptive non-coding evolution in humans. Genome Biol Evol 2022; 14:6648393. [PMID: 35866592 PMCID: PMC9348619 DOI: 10.1093/gbe/evac108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2022] [Indexed: 11/28/2022] Open
Abstract
The human and chimpanzee genomes are strikingly similar, but our neural phenotypes are very different. Many of these differences are likely driven by changes in gene expression, and some of those changes may have been adaptive during human evolution. Yet, the relative contributions of positive selection on regulatory regions or other functional regulatory changes are unclear. Where are these changes located throughout the human genome? Are functional regulatory changes near genes or are they in distal enhancer regions? In this study, we experimentally combined both human and chimpanzee cis-regulatory elements (CREs) that showed either (1) signs of accelerated evolution in humans or (2) that have been shown to be active in the human brain. Using a massively parallel reporter assay, we tested the ability of orthologous human and chimpanzee CREs to activate transcription in induced pluripotent stem-cell-derived neural progenitor cells and neurons. With this assay, we identified 179 CREs with differential activity between human and chimpanzee; in contrast, we found 722 CREs with signs of positive selection in humans. Selection and differentially expressed CREs strikingly differ in level of expression, size, and genomic location. We found a subset of 69 CREs in loci with genetic variants associated with neuropsychiatric diseases, which underscores the consequence of regulatory activity in these loci for proper neural development and function. By combining CREs that either experienced recent selection in humans or CREs that are functional brain enhancers, presents a novel way of studying the evolution of noncoding elements that contribute to human neural phenotypes.
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Affiliation(s)
- Jason Pizzollo
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA 01003, USA.,Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Trisha M Zintel
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA 01003, USA.,Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Courtney C Babbitt
- Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
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11
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Espinós A, Fernández‐Ortuño E, Negri E, Borrell V. Evolution of genetic mechanisms regulating cortical neurogenesis. Dev Neurobiol 2022; 82:428-453. [PMID: 35670518 PMCID: PMC9543202 DOI: 10.1002/dneu.22891] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/26/2022] [Accepted: 05/24/2022] [Indexed: 11/20/2022]
Abstract
The size of the cerebral cortex increases dramatically across amniotes, from reptiles to great apes. This is primarily due to different numbers of neurons and glial cells produced during embryonic development. The evolutionary expansion of cortical neurogenesis was linked to changes in neural stem and progenitor cells, which acquired increased capacity of self‐amplification and neuron production. Evolution works via changes in the genome, and recent studies have identified a small number of new genes that emerged in the recent human and primate lineages, promoting cortical progenitor proliferation and increased neurogenesis. However, most of the mammalian genome corresponds to noncoding DNA that contains gene‐regulatory elements, and recent evidence precisely points at changes in expression levels of conserved genes as key in the evolution of cortical neurogenesis. Here, we provide an overview of basic cellular mechanisms involved in cortical neurogenesis across amniotes, and discuss recent progress on genetic mechanisms that may have changed during evolution, including gene expression regulation, leading to the expansion of the cerebral cortex.
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Affiliation(s)
- Alexandre Espinós
- Instituto de Neurociencias CSIC ‐ UMH, 03550 Sant Joan d'Alacant Spain
| | | | - Enrico Negri
- Instituto de Neurociencias CSIC ‐ UMH, 03550 Sant Joan d'Alacant Spain
| | - Víctor Borrell
- Instituto de Neurociencias CSIC ‐ UMH, 03550 Sant Joan d'Alacant Spain
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12
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Schmidt ERE, Polleux F. Genetic Mechanisms Underlying the Evolution of Connectivity in the Human Cortex. Front Neural Circuits 2022; 15:787164. [PMID: 35069126 PMCID: PMC8777274 DOI: 10.3389/fncir.2021.787164] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/09/2021] [Indexed: 12/22/2022] Open
Abstract
One of the most salient features defining modern humans is our remarkable cognitive capacity, which is unrivaled by any other species. Although we still lack a complete understanding of how the human brain gives rise to these unique abilities, the past several decades have witnessed significant progress in uncovering some of the genetic, cellular, and molecular mechanisms shaping the development and function of the human brain. These features include an expansion of brain size and in particular cortical expansion, distinct physiological properties of human neurons, and modified synaptic development. Together they specify the human brain as a large primate brain with a unique underlying neuronal circuit architecture. Here, we review some of the known human-specific features of neuronal connectivity, and we outline how novel insights into the human genome led to the identification of human-specific genetic modifiers that played a role in the evolution of human brain development and function. Novel experimental paradigms are starting to provide a framework for understanding how the emergence of these human-specific genomic innovations shaped the structure and function of neuronal circuits in the human brain.
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Affiliation(s)
- Ewoud R. E. Schmidt
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
- *Correspondence: Ewoud R. E. Schmidt
| | - Franck Polleux
- Department of Neuroscience, Columbia University, New York, NY, United States
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, United States
- Kavli Institute for Brain Science, Columbia University, New York, NY, United States
- Franck Polleux
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13
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de la Torre-Ubieta L. Defining the evolutionary and gene regulatory logic of vertebrate neuronal diversity. Neuron 2022; 110:3-5. [PMID: 34990577 DOI: 10.1016/j.neuron.2021.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
How is the exquisite cellular complexity of the vertebrate brain achieved? In this issue of Neuron, Closser et al. (2022) reveal that an expanded neuronal gene regulatory landscape may drive evolutionary cellular diversification by providing complex context and cell-specific control of effector genes.
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Affiliation(s)
- Luis de la Torre-Ubieta
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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14
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Lipovsek M, Marcovich I, Elgoyhen AB. The Hair Cell α9α10 Nicotinic Acetylcholine Receptor: Odd Cousin in an Old Family. Front Cell Neurosci 2021; 15:785265. [PMID: 34867208 PMCID: PMC8634148 DOI: 10.3389/fncel.2021.785265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 10/25/2021] [Indexed: 11/13/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) are a subfamily of pentameric ligand-gated ion channels with members identified in most eumetazoan clades. In vertebrates, they are divided into three subgroups, according to their main tissue of expression: neuronal, muscle and hair cell nAChRs. Each receptor subtype is composed of different subunits, encoded by paralogous genes. The latest to be identified are the α9 and α10 subunits, expressed in the mechanosensory hair cells of the inner ear and the lateral line, where they mediate efferent modulation. α9α10 nAChRs are the most divergent amongst all nicotinic receptors, showing marked differences in their degree of sequence conservation, their expression pattern, their subunit co-assembly rules and, most importantly, their functional properties. Here, we review recent advances in the understanding of the structure and evolution of nAChRs. We discuss the functional consequences of sequence divergence and conservation, with special emphasis on the hair cell α9α10 receptor, a seemingly distant cousin of neuronal and muscle nicotinic receptors. Finally, we highlight potential links between the evolution of the octavolateral system and the extreme divergence of vertebrate α9α10 receptors.
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Affiliation(s)
- Marcela Lipovsek
- Ear Institute, Faculty of Brain Sciences, University College London, London, United Kingdom
| | - Irina Marcovich
- Departments of Otolaryngology & Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
| | - Ana Belén Elgoyhen
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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15
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Byer NW, Fountain ED, Reid BN, Miller K, Kulzer PJ, Peery MZ. Land use and life history constrain adaptive genetic variation and reduce the capacity for climate change adaptation in turtles. BMC Genomics 2021; 22:837. [PMID: 34794393 PMCID: PMC8603537 DOI: 10.1186/s12864-021-08151-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 11/01/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rapid anthropogenic climate change will require species to adapt to shifting environmental conditions, with successful adaptation dependent upon current patterns of genetic variation. While landscape genomic approaches allow for exploration of local adaptation in non-model systems, most landscape genomics studies of adaptive capacity are limited to exploratory identification of potentially important functional genes, often without a priori expectations as to the gene functions that may be most important for climate change responses. In this study, we integrated targeted sequencing of genes of known function and genotyping of single-nucleotide polymorphisms to examine spatial, environmental, and species-specific patterns of potential local adaptation in two co-occuring turtle species: the Blanding's turtle (Emydoidea blandingii) and the snapping turtle (Chelydra serpentina). RESULTS We documented divergent patterns of spatial clustering between neutral and putatively adaptive genetic variation in both species. Environmental associations varied among gene regions and between species, with stronger environmental associations detected for genes involved in stress response and for the more specialized Blanding's turtle. Land cover appeared to be more important than climate in shaping spatial variation in functional genes, indicating that human landscape alterations may affect adaptive capacity important for climate change responses. CONCLUSIONS Our study provides evidence that responses to climate change will be contingent on species-specific adaptive capacity and past history of exposure to human land cover change.
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Affiliation(s)
| | | | - Brendan N Reid
- W.K. Kellogg Biological Station, Michigan State University, MI, 49060, Hickory Corners, USA
| | - Kristen Miller
- University of Wisconsin-Madison, 53706, Madison, WI, USA
| | - Paige J Kulzer
- University of Wisconsin-Madison, 53706, Madison, WI, USA
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16
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Ferrari R, Grandi N, Tramontano E, Dieci G. Retrotransposons as Drivers of Mammalian Brain Evolution. Life (Basel) 2021; 11:life11050376. [PMID: 33922141 PMCID: PMC8143547 DOI: 10.3390/life11050376] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 12/11/2022] Open
Abstract
Retrotransposons, a large and diverse class of transposable elements that are still active in humans, represent a remarkable force of genomic innovation underlying mammalian evolution. Among the features distinguishing mammals from all other vertebrates, the presence of a neocortex with a peculiar neuronal organization, composition and connectivity is perhaps the one that, by affecting the cognitive abilities of mammals, contributed mostly to their evolutionary success. Among mammals, hominids and especially humans display an extraordinarily expanded cortical volume, an enrichment of the repertoire of neural cell types and more elaborate patterns of neuronal connectivity. Retrotransposon-derived sequences have recently been implicated in multiple layers of gene regulation in the brain, from transcriptional and post-transcriptional control to both local and large-scale three-dimensional chromatin organization. Accordingly, an increasing variety of neurodevelopmental and neurodegenerative conditions are being recognized to be associated with retrotransposon dysregulation. We review here a large body of recent studies lending support to the idea that retrotransposon-dependent evolutionary novelties were crucial for the emergence of mammalian, primate and human peculiarities of brain morphology and function.
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Affiliation(s)
- Roberto Ferrari
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy;
| | - Nicole Grandi
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy; (N.G.); (E.T.)
| | - Enzo Tramontano
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy; (N.G.); (E.T.)
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, 09042 Monserrato, Italy
| | - Giorgio Dieci
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy;
- Correspondence:
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17
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Marcovich I, Moglie MJ, Carpaneto Freixas AE, Trigila AP, Franchini LF, Plazas PV, Lipovsek M, Elgoyhen AB. Distinct Evolutionary Trajectories of Neuronal and Hair Cell Nicotinic Acetylcholine Receptors. Mol Biol Evol 2021; 37:1070-1089. [PMID: 31821508 PMCID: PMC7086180 DOI: 10.1093/molbev/msz290] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The expansion and pruning of ion channel families has played a crucial role in the evolution of nervous systems. Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels with distinct roles in synaptic transmission at the neuromuscular junction, the central and peripheral nervous system, and the inner ear. Remarkably, the complement of nAChR subunits has been highly conserved along vertebrate phylogeny. To ask whether the different subtypes of receptors underwent different evolutionary trajectories, we performed a comprehensive analysis of vertebrate nAChRs coding sequences, mouse single-cell expression patterns, and comparative functional properties of receptors from three representative tetrapod species. We found significant differences between hair cell and neuronal receptors that were most likely shaped by the differences in coexpression patterns and coassembly rules of component subunits. Thus, neuronal nAChRs showed high degree of coding sequence conservation, coupled to greater coexpression variance and conservation of functional properties across tetrapod clades. In contrast, hair cell α9α10 nAChRs exhibited greater sequence divergence, narrow coexpression pattern, and great variability of functional properties across species. These results point to differential substrates for random change within the family of gene paralogs that relate to the segregated roles of nAChRs in synaptic transmission.
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Affiliation(s)
- Irina Marcovich
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Marcelo J Moglie
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Agustín E Carpaneto Freixas
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Anabella P Trigila
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Lucia F Franchini
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Paola V Plazas
- Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Marcela Lipovsek
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.,Centre for Developmental Neurobiology, King's College London, Institute of Psychiatry, Psychology and Neuroscience, Guy's Campus, London, United Kingdom
| | - Ana Belén Elgoyhen
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.,Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
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18
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Uebbing S, Gockley J, Reilly SK, Kocher AA, Geller E, Gandotra N, Scharfe C, Cotney J, Noonan JP. Massively parallel discovery of human-specific substitutions that alter enhancer activity. Proc Natl Acad Sci U S A 2021; 118:e2007049118. [PMID: 33372131 PMCID: PMC7812811 DOI: 10.1073/pnas.2007049118] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Genetic changes that altered the function of gene regulatory elements have been implicated in the evolution of human traits such as the expansion of the cerebral cortex. However, identifying the particular changes that modified regulatory activity during human evolution remain challenging. Here we used massively parallel enhancer assays in neural stem cells to quantify the functional impact of >32,000 human-specific substitutions in >4,300 human accelerated regions (HARs) and human gain enhancers (HGEs), which include enhancers with novel activities in humans. We found that >30% of active HARs and HGEs exhibited differential activity between human and chimpanzee. We isolated the effects of human-specific substitutions from background genetic variation to identify the effects of genetic changes most relevant to human evolution. We found that substitutions interacted in both additive and nonadditive ways to modify enhancer function. Substitutions within HARs, which are highly constrained compared to HGEs, showed smaller effects on enhancer activity, suggesting that the impact of human-specific substitutions is buffered in enhancers with constrained ancestral functions. Our findings yield insight into how human-specific genetic changes altered enhancer function and provide a rich set of candidates for studies of regulatory evolution in humans.
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Affiliation(s)
- Severin Uebbing
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510
| | - Jake Gockley
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510
| | - Steven K Reilly
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510
| | - Acadia A Kocher
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510
| | - Evan Geller
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510
| | - Neeru Gandotra
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510
| | - Curt Scharfe
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510
| | - Justin Cotney
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510
| | - James P Noonan
- Department of Genetics, Yale School of Medicine, New Haven, CT 06510;
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520
- Department of Neuroscience, Yale School of Medicine, New Haven, CT 06510
- Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06510
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19
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Grogan KE, Perry GH. Studying human and nonhuman primate evolutionary biology with powerful in vitro and in vivo functional genomics tools. Evol Anthropol 2020; 29:143-158. [PMID: 32142200 PMCID: PMC10574139 DOI: 10.1002/evan.21825] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/18/2019] [Accepted: 02/06/2020] [Indexed: 12/19/2022]
Abstract
In recent years, tools for functional genomic studies have become increasingly feasible for use by evolutionary anthropologists. In this review, we provide brief overviews of several exciting in vitro techniques that can be paired with "-omics" approaches (e.g., genomics, epigenomics, transcriptomics, proteomics, and metabolomics) for potentially powerful evolutionary insights. These in vitro techniques include ancestral protein resurrection, cell line experiments using primary, immortalized, and induced pluripotent stem cells, and CRISPR-Cas9 genetic manipulation. We also discuss how several of these methods can be used in vivo, for transgenic organism studies of human and nonhuman primate evolution. Throughout this review, we highlight example studies in which these approaches have already been used to inform our understanding of the evolutionary biology of modern and archaic humans and other primates while simultaneously identifying future opportunities for anthropologists to use this toolkit to help answer additional outstanding questions in evolutionary anthropology.
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Affiliation(s)
- Kathleen E. Grogan
- Department of Anthropology, Pennsylvania State University, University Park, PA 16802
- Department of Biology, Pennsylvania State University, University Park, PA 16802
| | - George H. Perry
- Department of Anthropology, Pennsylvania State University, University Park, PA 16802
- Department of Biology, Pennsylvania State University, University Park, PA 16802
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
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20
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Bauernfeind AL, Babbitt CC. Metabolic changes in human brain evolution. Evol Anthropol 2020; 29:201-211. [PMID: 32329960 DOI: 10.1002/evan.21831] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 08/30/2019] [Accepted: 03/13/2020] [Indexed: 12/23/2022]
Abstract
Because the human brain is considerably larger than those of other primates, it is not surprising that its energy requirements would far exceed that of any of the species within the order. Recently, the development of stem cell technologies and single-cell transcriptomics provides novel ways to address the question of what specific genomic changes underlie the human brain's unique phenotype. In this review, we consider what is currently known about human brain metabolism using a variety of methods from brain imaging and stereology to transcriptomics. Next, we examine novel opportunities that stem cell technologies and single-cell transcriptomics provide to further our knowledge of human brain energetics. These new experimental approaches provide the ability to elucidate the functional effects of changes in genetic sequence and expression levels that potentially had a profound impact on the evolution of the human brain.
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Affiliation(s)
- Amy L Bauernfeind
- Department of Neuroscience, Washington University Medical School, St. Louis, Missouri, USA.,Department of Anthropology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Courtney C Babbitt
- Department of Biology, University of Massachusetts Amherst, Amherst, Massachusetts, USA
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21
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Edsall LE, Berrio A, Majoros WH, Swain-Lenz D, Morrow S, Shibata Y, Safi A, Wray GA, Crawford GE, Allen AS. Evaluating Chromatin Accessibility Differences Across Multiple Primate Species Using a Joint Modeling Approach. Genome Biol Evol 2019; 11:3035-3053. [PMID: 31599933 PMCID: PMC6821351 DOI: 10.1093/gbe/evz218] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2019] [Indexed: 12/13/2022] Open
Abstract
Changes in transcriptional regulation are thought to be a major contributor to the evolution of phenotypic traits, but the contribution of changes in chromatin accessibility to the evolution of gene expression remains almost entirely unknown. To address this important gap in knowledge, we developed a new method to identify DNase I Hypersensitive (DHS) sites with differential chromatin accessibility between species using a joint modeling approach. Our method overcomes several limitations inherent to conventional threshold-based pairwise comparisons that become increasingly apparent as the number of species analyzed rises. Our approach employs a single quantitative test which is more sensitive than existing pairwise methods. To illustrate, we applied our joint approach to DHS sites in fibroblast cells from five primates (human, chimpanzee, gorilla, orangutan, and rhesus macaque). We identified 89,744 DHS sites, of which 41% are identified as differential between species using the joint model compared with 33% using the conventional pairwise approach. The joint model provides a principled approach to distinguishing single from multiple chromatin accessibility changes among species. We found that nondifferential DHS sites are enriched for nucleotide conservation. Differential DHS sites with decreased chromatin accessibility relative to rhesus macaque occur more commonly near transcription start sites (TSS), while those with increased chromatin accessibility occur more commonly distal to TSS. Further, differential DHS sites near TSS are less cell type-specific than more distal regulatory elements. Taken together, these results point to distinct classes of DHS sites, each with distinct characteristics of selection, genomic location, and cell type specificity.
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Affiliation(s)
- Lee E Edsall
- Center for Genomic and Computational Biology, Duke University
- Division of Medical Genetics, Department of Pediatrics, Duke University
- University Program in Genetics and Genomics, Duke University
| | | | | | | | | | - Yoichiro Shibata
- Center for Genomic and Computational Biology, Duke University
- Division of Medical Genetics, Department of Pediatrics, Duke University
| | - Alexias Safi
- Center for Genomic and Computational Biology, Duke University
- Division of Medical Genetics, Department of Pediatrics, Duke University
| | - Gregory A Wray
- Center for Genomic and Computational Biology, Duke University
- Department of Biology, Duke University
| | - Gregory E Crawford
- Center for Genomic and Computational Biology, Duke University
- Division of Medical Genetics, Department of Pediatrics, Duke University
| | - Andrew S Allen
- Department of Biostatistics and Bioinformatics, Duke University
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22
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Cutter AD, Garrett RH, Mark S, Wang W, Sun L. Molecular evolution across developmental time reveals rapid divergence in early embryogenesis. Evol Lett 2019; 3:359-373. [PMID: 31388446 PMCID: PMC6675142 DOI: 10.1002/evl3.122] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 05/30/2019] [Indexed: 12/16/2022] Open
Abstract
Ontogenetic development hinges on the changes in gene expression in time and space within an organism, suggesting that the demands of ontogenetic growth can impose or reveal predictable pattern in the molecular evolution of genes expressed dynamically across development. Here, we characterize coexpression modules of the Caenorhabditis elegans transcriptome, using a time series of 30 points from early embryo to adult. By capturing the functional form of expression profiles with quantitative metrics, we find fastest evolution in the distinctive set of genes with transcript abundance that declines through development from a peak in young embryos. These genes are highly enriched for oogenic function and transient early zygotic expression, are nonrandomly distributed in the genome, and correspond to a life stage especially prone to inviability in interspecies hybrids. These observations conflict with the "early conservation model" for the evolution of development, although expression-weighted sequence divergence analysis provides some support for the "hourglass model." Genes in coexpression modules that peak toward adulthood also evolve fast, being hyper-enriched for roles in spermatogenesis, implicating a history of sexual selection and relaxation of selection on sperm as key factors driving rapid change to ontogenetically distinguishable coexpression modules of genes. We propose that these predictable trends of molecular evolution for dynamically expressed genes across ontogeny predispose particular life stages, early embryogenesis in particular, to hybrid dysfunction in the speciation process.
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Affiliation(s)
- Asher D. Cutter
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONM6G1W3Canada
| | - Rose H. Garrett
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONM6G1W3Canada
- Division of Biostatistics, Dalla Lana School of Public HealthUniversity of TorontoTorontoONM6G1W3Canada
- Department of Statistical SciencesUniversity of TorontoTorontoONM6G1W3Canada
| | - Stephanie Mark
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONM6G1W3Canada
| | - Wei Wang
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONM6G1W3Canada
| | - Lei Sun
- Division of Biostatistics, Dalla Lana School of Public HealthUniversity of TorontoTorontoONM6G1W3Canada
- Department of Statistical SciencesUniversity of TorontoTorontoONM6G1W3Canada
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23
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Vilgalys TP, Rogers J, Jolly CJ, Baboon Genome Analysis, Mukherjee S, Tung J. Evolution of DNA Methylation in Papio Baboons. Mol Biol Evol 2019; 36:527-540. [PMID: 30521003 PMCID: PMC6389319 DOI: 10.1093/molbev/msy227] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Changes in gene regulation have long been thought to play an important role in primate evolution. However, although a number of studies have compared genome-wide gene expression patterns across primate species, fewer have investigated the gene regulatory mechanisms that underlie such patterns, or the relative contribution of drift versus selection. Here, we profiled genome-scale DNA methylation levels in blood samples from five of the six extant species of the baboon genus Papio (4-14 individuals per species). This radiation presents the opportunity to investigate DNA methylation divergence at both shallow and deeper timescales (0.380-1.4 My). In contrast to studies in human populations, but similar to studies in great apes, DNA methylation profiles clearly mirror genetic and geographic structure. Divergence in DNA methylation proceeds fastest in unannotated regions of the genome and slowest in regions of the genome that are likely more constrained at the sequence level (e.g., gene exons). Both heuristic approaches and Ornstein-Uhlenbeck models suggest that DNA methylation levels at a small set of sites have been affected by positive selection, and that this class is enriched in functionally relevant contexts, including promoters, enhancers, and CpG islands. Our results thus indicate that the rate and distribution of DNA methylation changes across the genome largely mirror genetic structure. However, at some CpG sites, DNA methylation levels themselves may have been a target of positive selection, pointing to loci that could be important in connecting sequence variation to fitness-related traits.
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Affiliation(s)
- Tauras P Vilgalys
- Department of Evolutionary Anthropology, Duke University, Durham, NC
| | - Jeffrey Rogers
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Clifford J Jolly
- Department of Anthropology, New York University, New York, NY
- Center for the Study of Human Origins, New York University, New York, NY
- New York Consortium for Evolutionary Primatology, New York, NY
| | | | - Sayan Mukherjee
- Department of Statistical Science, Duke University, Durham, NC
- Department of Mathematics, Duke University, Durham, NC
- Department of Computer Science, Duke University, Durham, NC
| | - Jenny Tung
- Department of Evolutionary Anthropology, Duke University, Durham, NC
- Department of Biology, Duke University, Durham, NC
- Duke University Population Research Institute, Duke University, Durham, NC
- Institute of Primate Research, National Museums of Kenya, Karen, Nairobi, Kenya
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24
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Brown AP, Arias-Rodriguez L, Yee MC, Tobler M, Kelley JL. Concordant Changes in Gene Expression and Nucleotides Underlie Independent Adaptation to Hydrogen-Sulfide-Rich Environments. Genome Biol Evol 2018; 10:2867-2881. [PMID: 30215710 PMCID: PMC6225894 DOI: 10.1093/gbe/evy198] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2018] [Indexed: 12/23/2022] Open
Abstract
The colonization of novel environments often involves changes in gene expression, protein coding sequence, or both. Studies of how populations adapt to novel conditions, however, often focus on only one of these two processes, potentially missing out on the relative importance of different parts of the evolutionary process. In this study, our objectives were 1) to better understand the qualitative concordance between conclusions drawn from analyses of differential expression and changes in genic sequence and 2) to quantitatively test whether differentially expressed genes were enriched for sites putatively under positive selection within gene regions. To achieve this, we compared populations of fish (Poecilia mexicana) that have independently adapted to hydrogen-sulfide-rich environments in southern Mexico to adjacent populations residing in nonsulfidic waters. Specifically, we used RNA-sequencing data to compare both gene expression and DNA sequence differences between populations. Analyzing these two different data types led to similar conclusions about which biochemical pathways (sulfide detoxification and cellular respiration) were involved in adaptation to sulfidic environments. Additionally, we found a greater overlap between genes putatively under selection and differentially expressed genes than expected by chance. We conclude that considering both differential expression and changes in DNA sequence led to a more comprehensive understanding of how these populations adapted to extreme environmental conditions. Our results imply that changes in both gene expression and DNA sequence-sometimes at the same loci-may be involved in adaptation.
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Affiliation(s)
- Anthony P Brown
- School of Biological Sciences, Washington State University, 100 Dairy Road, Pullman, WA 99164
| | - Lenin Arias-Rodriguez
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco (UJAT), C.P. 86150, Villahermosa, Tabasco, México
| | - Muh-Ching Yee
- Stanford Functional Genomics Facility, CCSR 0120, Stanford, CA 94305
| | - Michael Tobler
- Division of Biology, Kansas State University, 116 Ackert Hall, Manhattan, KS 66506
| | - Joanna L Kelley
- School of Biological Sciences, Washington State University, 100 Dairy Road, Pullman, WA 99164
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25
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Rivas MJ, Saura M, Pérez-Figueroa A, Panova M, Johansson T, André C, Caballero A, Rolán-Alvarez E, Johannesson K, Quesada H. Population genomics of parallel evolution in gene expression and gene sequence during ecological adaptation. Sci Rep 2018; 8:16147. [PMID: 30385764 PMCID: PMC6212547 DOI: 10.1038/s41598-018-33897-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 10/08/2018] [Indexed: 11/17/2022] Open
Abstract
Natural selection often produces parallel phenotypic changes in response to a similar adaptive challenge. However, the extent to which parallel gene expression differences and genomic divergence underlie parallel phenotypic traits and whether they are decoupled or not remains largely unexplored. We performed a population genomic study of parallel ecological adaptation among replicate ecotype pairs of the rough periwinkle (Littorina saxatilis) at a regional geographical scale (NW Spain). We show that genomic changes underlying parallel phenotypic divergence followed a complex pattern of both repeatable differences and of differences unique to specific ecotype pairs, in which parallel changes in expression or sequence are restricted to a limited set of genes. Yet, the majority of divergent genes were divergent either for gene expression or coding sequence, but not for both simultaneously. Overall, our findings suggest that divergent selection significantly contributed to the process of parallel molecular differentiation among ecotype pairs, and that changes in expression and gene sequence underlying phenotypic divergence could, at least to a certain extent, be considered decoupled processes.
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Affiliation(s)
- María José Rivas
- Departamento de Bioquímica, Genética e Inmunología, Universidad de Vigo, 36310, Vigo, Spain
| | - María Saura
- Departamento de Bioquímica, Genética e Inmunología, Universidad de Vigo, 36310, Vigo, Spain
| | - Andrés Pérez-Figueroa
- Departamento de Bioquímica, Genética e Inmunología, Universidad de Vigo, 36310, Vigo, Spain
| | - Marina Panova
- Department of Marine Sciences, Tjärnö, University of Gothenburg, SE-452 96, Strömstad, Sweden
| | - Tomas Johansson
- Department of Biology, University of Lund, SE-223 62, Lund, Sweden
| | - Carl André
- Department of Marine Sciences, Tjärnö, University of Gothenburg, SE-452 96, Strömstad, Sweden
| | - Armando Caballero
- Departamento de Bioquímica, Genética e Inmunología, Universidad de Vigo, 36310, Vigo, Spain
| | - Emilio Rolán-Alvarez
- Departamento de Bioquímica, Genética e Inmunología, Universidad de Vigo, 36310, Vigo, Spain
| | - Kerstin Johannesson
- Department of Marine Sciences, Tjärnö, University of Gothenburg, SE-452 96, Strömstad, Sweden
| | - Humberto Quesada
- Departamento de Bioquímica, Genética e Inmunología, Universidad de Vigo, 36310, Vigo, Spain.
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26
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Gene expression variability across cells and species shapes innate immunity. Nature 2018; 563:197-202. [PMID: 30356220 PMCID: PMC6347972 DOI: 10.1038/s41586-018-0657-2] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 08/17/2018] [Indexed: 11/09/2022]
Abstract
As the first line of defence against pathogens, cells mount an innate immune response, which varies widely from cell to cell. The response must be potent but carefully controlled to avoid self-damage. How these constraints have shaped the evolution of innate immunity remains poorly understood. Here we characterize the innate immune response's transcriptional divergence between species and variability in expression among cells. Using bulk and single-cell transcriptomics in fibroblasts and mononuclear phagocytes from different species, challenged with immune stimuli, we map the architecture of the innate immune response. Transcriptionally diverging genes, including those that encode cytokines and chemokines, vary across cells and have distinct promoter structures. Conversely, genes that are involved in the regulation of this response, such as those that encode transcription factors and kinases, are conserved between species and display low cell-to-cell variability in expression. We suggest that this expression pattern, which is observed across species and conditions, has evolved as a mechanism for fine-tuned regulation to achieve an effective but balanced response.
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27
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Suzuki S, Miyabe E, Inagaki S. Novel brain-expressed noncoding RNA, HSTR1, identified at a human-specific variable number tandem repeat locus with a human accelerated region. Biochem Biophys Res Commun 2018; 503:1478-1483. [PMID: 30029879 DOI: 10.1016/j.bbrc.2018.07.066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 07/12/2018] [Indexed: 12/27/2022]
Abstract
The evolutionary conserved genomic sequences that have acquired significantly increased number of nucleotide substitutions specifically in the human lineage, called human accelerated regions (HARs), have been identified as candidate genomic regions that have contributed to the evolution of human-specific traits. A number of HARs were indeed shown to have novel enhancer activity and be associated with human-specific brain development and with cognition and social behavior. It is therefore of great importance to investigate the details of genomic function of each HAR to understand the roles of HARs as critical contributors to the genetic basis of human evolution. In this study, we identified a previously unannotated brain-expressed noncoding RNA gene, HSTR1, at a human-specific tandem repeat locus. Notably, the 5' flanking sequence of HSTR1 showed the signature of HARs and the dramatic human-specific enhancement of promoter activity, providing the evidence of positive selection to increase the expression level of HSTR1 during human evolution. We also revealed that the tandem repeat number in HSTR1 was highly variable among individual alleles and affected the stability of HSTR1 RNA, suggesting variation in the activity of HSTR1 between human individuals. Our work thus provides a novel candidate gene that potentially contributed to the evolution of the human brain. It may also underpin some of the variation between human brains.
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Affiliation(s)
- Shunsuke Suzuki
- Department of Agriculture, Graduate School of Science and Technology, Shinshu University, 8304 Minami-Minowa, Kami-Ina, Nagano, 399-4598, Japan; Department of Interdisciplinary Genome Sciences and Cell Metabolism, Institute for Biomedical Sciences, ICCER, Shinshu University, 8304 Minami-Minowa, Kami-Ina, Nagano, 399-4598, Japan.
| | - Emi Miyabe
- Department of Agriculture, Graduate School of Science and Technology, Shinshu University, 8304 Minami-Minowa, Kami-Ina, Nagano, 399-4598, Japan
| | - Shun Inagaki
- Department of Agriculture, Graduate School of Science and Technology, Shinshu University, 8304 Minami-Minowa, Kami-Ina, Nagano, 399-4598, Japan
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28
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Staes N, Bradley BJ, Hopkins WD, Sherwood CC. Genetic signatures of socio-communicative abilities in primates. Curr Opin Behav Sci 2018. [DOI: 10.1016/j.cobeha.2017.11.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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29
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Vlahovic I, Gluncic M, Rosandic M, Ugarkovic Ð, Paar V. Regular Higher Order Repeat Structures in Beetle Tribolium castaneum Genome. Genome Biol Evol 2018; 9:2668-2680. [PMID: 27492235 PMCID: PMC5737470 DOI: 10.1093/gbe/evw174] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/21/2016] [Indexed: 02/07/2023] Open
Abstract
Higher order repeats (HORs) containing tandems of primary and secondary repeat units (head-to-tail “tandem within tandem pattern”), referred to as regular HORs, are typical for primate alpha satellite DNAs and most pronounced in human genome. Regular HORs are known to be a result of recent evolutionary processes. In non-primate genomes mostly so called complex HORs have been found, without head to tail tandem of primary repeat units. In beetle Tribolium castaneum, considered as a model case for genome studies, large tandem repeats have been identified, but no HORs have been reported. Here, using our novel robust repeat finding algorithm Global Repeat Map, we discover two regular and six complex HORs in T. castaneum. In organizational pattern, the integrity and homogeneity of regular HORs in T. castaneum resemble human regular HORs (with T. castaneum monomers different from human alpha satellite monomers), involving a wider range of monomer lengths than in human HORs. Similar regular higher order repeat structures have previously not been found in insects. Some of these novel HORs in T. castaneum appear as most regular among known HORs in non-primate genomes, although with substantial riddling. This is intriguing, in particular from the point of view of role of non-coding repeats in modulation of gene expression.
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Affiliation(s)
- Ines Vlahovic
- Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Matko Gluncic
- Faculty of Science, University of Zagreb, Zagreb, Croatia
| | | | | | - Vladimir Paar
- Faculty of Science, University of Zagreb, Zagreb, Croatia.,Croatian Academy of Sciences and Arts, Zagreb, Croatia
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30
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Congrains C, Campanini EB, Torres FR, Rezende VB, Nakamura AM, de Oliveira JL, Lima ALA, Chahad-Ehlers S, Sobrinho IS, de Brito RA. Evidence of Adaptive Evolution and Relaxed Constraints in Sex-Biased Genes of South American and West Indies Fruit Flies (Diptera: Tephritidae). Genome Biol Evol 2018; 10:380-395. [PMID: 29346618 PMCID: PMC5786236 DOI: 10.1093/gbe/evy009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/11/2018] [Indexed: 12/29/2022] Open
Abstract
Several studies have demonstrated that genes differentially expressed between sexes (sex-biased genes) tend to evolve faster than unbiased genes, particularly in males. The reason for this accelerated evolution is not clear, but several explanations have involved adaptive and nonadaptive mechanisms. Furthermore, the differences of sex-biased expression patterns of closely related species are also little explored out of Drosophila. To address the evolutionary processes involved with sex-biased expression in species with incipient differentiation, we analyzed male and female transcriptomes of Anastrepha fraterculus and Anastrepha obliqua, a pair of species that have diverged recently, likely in the presence of gene flow. Using these data, we inferred differentiation indexes and evolutionary rates and tested for signals of selection in thousands of genes expressed in head and reproductive transcriptomes from both species. Our results indicate that sex-biased and reproductive-biased genes evolve faster than unbiased genes in both species, which is due to both adaptive pressure and relaxed constraints. Furthermore, among male-biased genes evolving under positive selection, we identified some related to sexual functions such as courtship behavior and fertility. These findings suggest that sex-biased genes may have played important roles in the establishment of reproductive isolation between these species, due to a combination of selection and drift, and unveil a plethora of genetic markers useful for more studies in these species and their differentiation.
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Affiliation(s)
- Carlos Congrains
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, SP, Brazil
| | - Emeline B Campanini
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, SP, Brazil
| | - Felipe R Torres
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, SP, Brazil
| | - Víctor B Rezende
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, SP, Brazil
| | - Aline M Nakamura
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, SP, Brazil
| | | | - André L A Lima
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, SP, Brazil
| | - Samira Chahad-Ehlers
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, SP, Brazil
| | | | - Reinaldo A de Brito
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, SP, Brazil
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31
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Levchenko A, Kanapin A, Samsonova A, Gainetdinov RR. Human Accelerated Regions and Other Human-Specific Sequence Variations in the Context of Evolution and Their Relevance for Brain Development. Genome Biol Evol 2018; 10:166-188. [PMID: 29149249 PMCID: PMC5767953 DOI: 10.1093/gbe/evx240] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2017] [Indexed: 12/24/2022] Open
Abstract
The review discusses, in a format of a timeline, the studies of different types of genetic variants, present in Homo sapiens, but absent in all other primate, mammalian, or vertebrate species, tested so far. The main characteristic of these variants is that they are found in regions of high evolutionary conservation. These sequence variations include single nucleotide substitutions (called human accelerated regions), deletions, and segmental duplications. The rationale for finding such variations in the human genome is that they could be responsible for traits, specific to our species, of which the human brain is the most remarkable. As became obvious, the vast majority of human-specific single nucleotide substitutions are found in noncoding, likely regulatory regions. A number of genes, associated with these human-specific alleles, often through novel enhancer activity, were in fact shown to be implicated in human-specific development of certain brain areas, including the prefrontal cortex. Human-specific deletions may remove regulatory sequences, such as enhancers. Segmental duplications, because of their large size, create new coding sequences, like new functional paralogs. Further functional study of these variants will shed light on evolution of our species, as well as on the etiology of neurodevelopmental disorders.
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Affiliation(s)
- Anastasia Levchenko
- Institute of Translational Biomedicine, Saint Petersburg State University, Russia
| | - Alexander Kanapin
- Institute of Translational Biomedicine, Saint Petersburg State University, Russia
- Department of Oncology, University of Oxford, United Kingdom
| | - Anastasia Samsonova
- Institute of Translational Biomedicine, Saint Petersburg State University, Russia
- Department of Oncology, University of Oxford, United Kingdom
| | - Raul R Gainetdinov
- Institute of Translational Biomedicine, Saint Petersburg State University, Russia
- Skolkovo Institute of Science and Technology, Skolkovo, Moscow, Russia
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32
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FOXP2 variation in great ape populations offers insight into the evolution of communication skills. Sci Rep 2017; 7:16866. [PMID: 29203828 PMCID: PMC5715162 DOI: 10.1038/s41598-017-16844-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 11/17/2017] [Indexed: 12/13/2022] Open
Abstract
The gene coding for the forkhead box protein P2 (FOXP2) is associated with human language disorders. Evolutionary changes in this gene are hypothesized to have contributed to the emergence of speech and language in the human lineage. Although FOXP2 is highly conserved across most mammals, humans differ at two functional amino acid substitutions from chimpanzees, bonobos and gorillas, with an additional fixed substitution found in orangutans. However, FOXP2 has been characterized in only a small number of apes and no publication to date has examined the degree of natural variation in large samples of unrelated great apes. Here, we analyzed the genetic variation in the FOXP2 coding sequence in 63 chimpanzees, 11 bonobos, 48 gorillas, 37 orangutans and 2 gibbons and observed undescribed variation in great apes. We identified two variable polyglutamine microsatellites in chimpanzees and orangutans and found three nonsynonymous single nucleotide polymorphisms, one in chimpanzees, one in gorillas and one in orangutans with derived allele frequencies of 0.01, 0.26 and 0.29, respectively. Structural and functional protein modeling indicate a biochemical effect of the substitution in orangutans, and because of its presence solely in the Sumatran orangutan species, the mutation may be associated with reported population differences in vocalizations.
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33
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Boddy AM, Harrison PW, Montgomery SH, Caravas JA, Raghanti MA, Phillips KA, Mundy NI, Wildman DE. Evidence of a Conserved Molecular Response to Selection for Increased Brain Size in Primates. Genome Biol Evol 2017; 9:700-713. [PMID: 28391320 PMCID: PMC5381557 DOI: 10.1093/gbe/evx028] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/23/2017] [Indexed: 12/12/2022] Open
Abstract
The adaptive significance of human brain evolution has been frequently studied through comparisons with other primates. However, the evolution of increased brain size is not restricted to the human lineage but is a general characteristic of primate evolution. Whether or not these independent episodes of increased brain size share a common genetic basis is unclear. We sequenced and de novo assembled the transcriptome from the neocortical tissue of the most highly encephalized nonhuman primate, the tufted capuchin monkey (Cebus apella). Using this novel data set, we conducted a genome-wide analysis of orthologous brain-expressed protein coding genes to identify evidence of conserved gene–phenotype associations and species-specific adaptations during three independent episodes of brain size increase. We identify a greater number of genes associated with either total brain mass or relative brain size across these six species than show species-specific accelerated rates of evolution in individual large-brained lineages. We test the robustness of these associations in an expanded data set of 13 species, through permutation tests and by analyzing how genome-wide patterns of substitution co-vary with brain size. Many of the genes targeted by selection during brain expansion have glutamatergic functions or roles in cell cycle dynamics. We also identify accelerated evolution in a number of individual capuchin genes whose human orthologs are associated with human neuropsychiatric disorders. These findings demonstrate the value of phenotypically informed genome analyses, and suggest at least some aspects of human brain evolution have occurred through conserved gene–phenotype associations. Understanding these commonalities is essential for distinguishing human-specific selection events from general trends in brain evolution.
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Affiliation(s)
- Amy M Boddy
- The Biodesign Institute, Arizona State University, Tempe, AZ.,Wayne State University School of Medicine, Center for Molecular Medicine and Genetics, Detroit, Michigan, Detroit, MI
| | - Peter W Harrison
- Department of Genetics Evolution & Environment, University College London, United Kingdom.,European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Stephen H Montgomery
- Department of Genetics Evolution & Environment, University College London, United Kingdom.,Department of Zoology, University of Cambridge, United Kingdom
| | - Jason A Caravas
- Wayne State University School of Medicine, Center for Molecular Medicine and Genetics, Detroit, Michigan, Detroit, MI
| | - Mary Ann Raghanti
- Department of Anthropology and School of Biomedical Sciences, Kent State University, Kent, OH
| | | | | | - Derek E Wildman
- Wayne State University School of Medicine, Center for Molecular Medicine and Genetics, Detroit, Michigan, Detroit, MI.,Department of Molecular & Integrative Physiology, University of Illinois, Urbana-Champaign, Urbana, IL.,Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana-Champaign, Urbana, IL
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34
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Enhancing our brains: Genomic mechanisms underlying cortical evolution. Semin Cell Dev Biol 2017; 76:23-32. [PMID: 28864345 DOI: 10.1016/j.semcdb.2017.08.045] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Accepted: 08/24/2017] [Indexed: 12/31/2022]
Abstract
Our most distinguishing higher cognitive functions are controlled by the cerebral cortex. Comparative studies detail abundant anatomical and cellular features unique to the human developing and adult neocortex. Emerging genomic studies have further defined vast differences distinguishing developing human neocortices from related primates. These human-specific changes can affect gene function and/or expression, and result from structural variations such as chromosomal deletions and duplications, or from point mutations in coding and noncoding regulatory regions. Here, we review this rapidly growing field which aims to identify and characterize genetic loci unique to the human cerebral cortex. We catalog known human-specific genomic changes distinct from other primates, including those whose function has been interrogated in animal models. We also discuss how new model systems and technologies such as single cell RNA sequencing, primate iPSCs, and gene editing, are enabling the field to gain unprecedented resolution into function of these human-specific changes. Some neurological disorders are thought to uniquely present in humans, thus reinforcing the need to comprehensively understand human-specific gene expression in the developing brain.
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35
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Sousa AMM, Meyer KA, Santpere G, Gulden FO, Sestan N. Evolution of the Human Nervous System Function, Structure, and Development. Cell 2017; 170:226-247. [PMID: 28708995 DOI: 10.1016/j.cell.2017.06.036] [Citation(s) in RCA: 216] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 04/21/2017] [Accepted: 06/22/2017] [Indexed: 12/22/2022]
Abstract
The nervous system-in particular, the brain and its cognitive abilities-is among humans' most distinctive and impressive attributes. How the nervous system has changed in the human lineage and how it differs from that of closely related primates is not well understood. Here, we consider recent comparative analyses of extant species that are uncovering new evidence for evolutionary changes in the size and the number of neurons in the human nervous system, as well as the cellular and molecular reorganization of its neural circuits. We also discuss the developmental mechanisms and underlying genetic and molecular changes that generate these structural and functional differences. As relevant new information and tools materialize at an unprecedented pace, the field is now ripe for systematic and functionally relevant studies of the development and evolution of human nervous system specializations.
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Affiliation(s)
- André M M Sousa
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA
| | - Kyle A Meyer
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA
| | - Gabriel Santpere
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA
| | - Forrest O Gulden
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA
| | - Nenad Sestan
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA; Department of Genetics, Yale School of Medicine, New Haven, CT, USA; Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA; Section of Comparative Medicine, Yale School of Medicine, New Haven, CT, USA; Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale School of Medicine, New Haven, CT, USA; Yale Child Study Center, Yale School of Medicine, New Haven, CT, USA; Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT, USA.
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36
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Nakajima R, Sato T, Ogawa T, Okano H, Noce T. A noncoding RNA containing a SINE-B1 motif associates with meiotic metaphase chromatin and has an indispensable function during spermatogenesis. PLoS One 2017; 12:e0179585. [PMID: 28658256 PMCID: PMC5489172 DOI: 10.1371/journal.pone.0179585] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 06/01/2017] [Indexed: 12/24/2022] Open
Abstract
A search for early response genes that are activated following germ cell induction from mouse embryonic stem cells in vitro led us to the isolation of a long noncoding RNA that contains a SINE (short interspersed element)-B1F motif that was named R53. In situ hybridization and northern blot analyses revealed that the R53 subfragment RNA bears a B1F motif, is processed from the primary transcript, is expressed in adult testis and is predominantly localized in meiotic metaphase chromatin during spermatogenesis. Recent studies of chromosome-associated RNAs have explored novel functions of noncoding RNAs. Specifically, chromosome-bound noncoding RNAs function not only as structural components of chromosome but also as scaffolds that recruit epigenetic modulators for transcriptional regulation, and they are dynamically rearranged during the cell cycle. However, few studies have explored meiotic chromatin; thus, R53 RNA appears to be the first long noncoding RNA to be tightly associated with the metaphase chromatin during spermatogenesis. Furthermore, R53 knockdown using a lentivirus-mediated RNAi injected into mouse testis and organ culture of the fragments revealed a remarkable reduction in postmeiotic cells and irregular up-regulation of several postmeiotic genes, which suggests the possibility that the SINE-B1-derived noncoding RNA R53 plays an indispensable role in the transcriptional regulation of key spermatogenesis genes.
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Affiliation(s)
- Ryusuke Nakajima
- Department of Physiology, Keio University School of Medicine, 35 Shinamomachi, Shinjuku-ku, Tokyo, Japan
- * E-mail: (RN); (TN)
| | - Takuya Sato
- Laboratory of Proteomics, Institute of Molecular Medicine and Life Science, Yokohama City University Association of Medical Science, Yokohama, Kanagawa, Japan
| | - Takehiko Ogawa
- Laboratory of Proteomics, Institute of Molecular Medicine and Life Science, Yokohama City University Association of Medical Science, Yokohama, Kanagawa, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, 35 Shinamomachi, Shinjuku-ku, Tokyo, Japan
| | - Toshiaki Noce
- Department of Physiology, Keio University School of Medicine, 35 Shinamomachi, Shinjuku-ku, Tokyo, Japan
- * E-mail: (RN); (TN)
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37
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Babbitt CC, Haygood R, Nielsen WJ, Wray GA. Gene expression and adaptive noncoding changes during human evolution. BMC Genomics 2017; 18:435. [PMID: 28583075 PMCID: PMC5460488 DOI: 10.1186/s12864-017-3831-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 05/31/2017] [Indexed: 01/14/2023] Open
Abstract
Background Despite evidence for adaptive changes in both gene expression and non-protein-coding, putatively regulatory regions of the genome during human evolution, the relationship between gene expression and adaptive changes in cis-regulatory regions remains unclear. Results Here we present new measurements of gene expression in five tissues of humans and chimpanzees, and use them to assess this relationship. We then compare our results with previous studies of adaptive noncoding changes, analyzing correlations at the level of gene ontology groups, in order to gain statistical power to detect correlations. Conclusions Consistent with previous studies, we find little correlation between gene expression and adaptive noncoding changes at the level of individual genes; however, we do find significant correlations at the level of biological function ontology groups. The types of function include processes regulated by specific transcription factors, responses to genetic or chemical perturbations, and differentiation of cell types within the immune system. Among functional categories co-enriched with both differential expression and noncoding adaptation, prominent themes include cancer, particularly epithelial cancers, and neural development and function. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3831-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Courtney C Babbitt
- Department of Biology, Duke University, Durham, NC, 27708, USA. .,Institute for Genome Sciences & Policy, Duke University, Durham, NC, 27708, USA. .,Present Address: Department of Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA.
| | | | | | - Gregory A Wray
- Department of Biology, Duke University, Durham, NC, 27708, USA.,Institute for Genome Sciences & Policy, Duke University, Durham, NC, 27708, USA.,Department of Evolutionary Anthropology, Duke University, Durham, NC, 27708, USA
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38
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Meyer KA, Marques-Bonet T, Sestan N. Differential Gene Expression in the Human Brain Is Associated with Conserved, but Not Accelerated, Noncoding Sequences. Mol Biol Evol 2017; 34:1217-1229. [PMID: 28204568 PMCID: PMC5400397 DOI: 10.1093/molbev/msx076] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Previous studies have found that genes which are differentially expressed within the developing human brain disproportionately neighbor conserved noncoding sequences (CNSs) that have an elevated substitution rate in humans and in other species. One explanation for this general association of differential expression with accelerated CNSs is that genes with pre-existing patterns of differential expression have been preferentially targeted by species-specific regulatory changes. Here we provide support for an alternative explanation: genes that neighbor a greater number of CNSs have a higher probability of differential expression and a higher probability of neighboring a CNS with lineage-specific acceleration. Thus, neighboring an accelerated element from any species signals that a gene likely neighbors many CNSs. We extend the analyses beyond the prenatal time points considered in previous studies to demonstrate that this association persists across developmental and adult periods. Examining differential expression between non-neural tissues suggests that the relationship between the number of CNSs a gene neighbors and its differential expression status may be particularly strong for expression differences among brain regions. In addition, by considering this relationship, we highlight a recently defined set of putative human-specific gain-of-function sequences that, even after adjusting for the number of CNSs neighbored by genes, shows a positive relationship with upregulation in the brain compared with other tissues examined.
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Affiliation(s)
- Kyle A. Meyer
- Department of Neuroscience and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT
| | - Tomas Marques-Bonet
- Institute of Evolutionary Biology (UPF-CSIC), PRBB, Barcelona, Spain
- Catalan Institution of Research and Advanced Studies (ICREA), Passeig de Lluís Companys, Barcelona, Spain
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Nenad Sestan
- Department of Neuroscience and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT
- Departments of Genetics and Psychiatry, Section of Comparative Medicine, Program in Cellular Neuroscience, Neurodegeneration and Repair, and Yale Child Study Center, Yale School of Medicine, New Haven, CT
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39
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Abstract
As a species, we possess unique biological features that distinguish us from other primates. Here, we review recent efforts to identify changes in gene regulation that drove the evolution of novel human phenotypes. We discuss genotype-directed comparisons of human and nonhuman primate genomes to identify human-specific genetic changes that may encode new regulatory functions. We also review phenotype-directed approaches, which use comparisons of gene expression or regulatory function in homologous human and nonhuman primate cells and tissues to identify changes in expression levels or regulatory activity that may be due to genetic changes in humans. Together, these studies are beginning to reveal the landscape of regulatory innovation in human evolution and point to specific regulatory changes for further study. Finally, we highlight two novel strategies to model human-specific regulatory functions in vivo: primate induced pluripotent stem cells and the generation of humanized mice by genome editing.
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Affiliation(s)
- Steven K Reilly
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06510;
| | - James P Noonan
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06510; .,Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut 06511.,Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, Connecticut 06510
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40
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Mills JD, Ward M, Chen BJ, Iyer AM, Aronica E, Janitz M. LINC00507 Is Specifically Expressed in the Primate Cortex and Has Age-Dependent Expression Patterns. J Mol Neurosci 2016; 59:431-9. [PMID: 27059230 DOI: 10.1007/s12031-016-0745-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 03/22/2016] [Indexed: 01/24/2023]
Abstract
Over the past decade, there has been an increase in the appreciation of the role of non-coding RNA in the development of organism phenotype. It is possible to divide the non-coding elements of the transcriptome into three categories: short non-coding RNAs, circular RNAs and long non-coding RNAs. Long non-coding RNAs are those transcripts that are greater than 200 nts in length and lack any significant open reading frames that produce proteins greater then 100 amino acids. Long intervening non-coding RNAs (lincRNAs) are a subclass of long non-coding RNAs. In contrast to protein coding RNAs, lincRNAs are expressed in a more tissue- and species-specific manner. In particular, many lincRNAs are only conserved amongst higher primates. This coupled with the propensity of many lincRNAs to be expressed in the brain, suggests that they are in fact one of the major drivers of organism complexity. We analysed 39 lincRNAs that are expressed in the frontal cortex and identified LINC00507 as being expressed in a cortex-specific manner in non-human primates and humans. The expression patterns of LINC00507 appear to be age-dependent, suggesting it may be involved in brain development of higher primates. Moreover, the analysis of LINC00507 potential to bind ribosomes revealed that this previously identified non-coding transcript may harbour a micropeptide.
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Affiliation(s)
- James D Mills
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, NSW, Sydney, 2052, Australia.,Department of (Neuro) Pathology, Academic Medical Center and Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
| | - Melanie Ward
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, NSW, Sydney, 2052, Australia
| | - Bei Jun Chen
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, NSW, Sydney, 2052, Australia
| | - Anand M Iyer
- Department of (Neuro) Pathology, Academic Medical Center and Swammerdam Institute for Life Sciences, Center for Neuorscience, University of Amsterdam, Amsterdam, The Netherlands
| | - Eleonora Aronica
- Department of (Neuro) Pathology, Academic Medical Center and Swammerdam Institute for Life Sciences, Center for Neuorscience, University of Amsterdam, Amsterdam, The Netherlands
| | - Michael Janitz
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, NSW, Sydney, 2052, Australia.
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41
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Epigenomic annotation of gene regulatory alterations during evolution of the primate brain. Nat Neurosci 2016; 19:494-503. [PMID: 26807951 DOI: 10.1038/nn.4229] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 12/21/2015] [Indexed: 12/16/2022]
Abstract
Although genome sequencing has identified numerous noncoding alterations between primate species, which of those are regulatory and potentially relevant to the evolution of the human brain is unclear. Here we annotated cis-regulatory elements (CREs) in the human, rhesus macaque and chimpanzee genomes using chromatin immunoprecipitation followed by sequencing (ChIP-seq) in different anatomical regions of the adult brain. We found high similarity in the genomic positioning of rhesus macaque and human CREs, suggesting that the majority of these elements were already present in a common ancestor 25 million years ago. Most of the observed regulatory changes between humans and rhesus macaques occurred before the ancestral separation of humans and chimpanzees, leaving a modest set of regulatory elements with predicted human specificity. Our data refine previous predictions and hypotheses on the consequences of genomic changes between primate species and allow the identification of regulatory alterations relevant to the evolution of the brain.
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42
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Bery A, Mérot Y, Rétaux S. Genes expressed in mouse cortical progenitors are enriched in Pax, Lhx, and Sox transcription factor putative binding sites. Brain Res 2015; 1633:37-51. [PMID: 26721689 DOI: 10.1016/j.brainres.2015.12.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 11/25/2015] [Accepted: 12/14/2015] [Indexed: 11/19/2022]
Abstract
Considerable progress has been made in the understanding of molecular and cellular mechanisms controlling the development of the mammalian cortex. The proliferative and neurogenic properties of cortical progenitors located in the ventricular germinal zone start being understood. Little is known however on the cis-regulatory control that finely tunes gene expression in these progenitors. Here, we undertook an in silico-based approach to address this question, followed by some functional validation. Using the Eurexpress database, we established a list of 30 genes specifically expressed in the cortical germinal zone, we selected mouse/human conserved non-coding elements (CNEs) around these genes and we performed motif-enrichment search in these CNEs. We found an over-representation of motifs corresponding to binding sites for Pax, Sox, and Lhx transcription factors, often found as pairs and located within 100bp windows. A small subset of CNEs (n=7) was tested for enhancer activity, by ex-vivo and in utero electroporation assays. Two showed strong enhancer activity in the germinal zone progenitors. Mutagenesis experiments on a selected CNE showed the functional importance of the Pax, Sox, and Lhx TFBS for conferring enhancer activity to the CNE. Overall, from a cis-regulatory viewpoint, our data suggest an input from Pax, Sox and Lhx transcription factors to orchestrate corticogenesis. These results are discussed with regards to the known functional roles of Pax6, Sox2 and Lhx2 in cortical development.
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Affiliation(s)
- Amandine Bery
- DECA Group, Institut des Neurosciences Paris-Saclay, Université Paris-Saclay, Université Paris-Sud, CNRS, UMR 9197, 91198 Gif-sur-Yvette, France.
| | - Yohann Mérot
- DECA Group, Institut des Neurosciences Paris-Saclay, Université Paris-Saclay, Université Paris-Sud, CNRS, UMR 9197, 91198 Gif-sur-Yvette, France
| | - Sylvie Rétaux
- DECA Group, Institut des Neurosciences Paris-Saclay, Université Paris-Saclay, Université Paris-Sud, CNRS, UMR 9197, 91198 Gif-sur-Yvette, France.
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43
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Hirbo J, Eidem H, Rokas A, Abbot P. Integrating Diverse Types of Genomic Data to Identify Genes that Underlie Adverse Pregnancy Phenotypes. PLoS One 2015; 10:e0144155. [PMID: 26641094 PMCID: PMC4671692 DOI: 10.1371/journal.pone.0144155] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/14/2015] [Indexed: 11/18/2022] Open
Abstract
Progress in understanding complex genetic diseases has been bolstered by synthetic approaches that overlay diverse data types and analyses to identify functionally important genes. Pre-term birth (PTB), a major complication of pregnancy, is a leading cause of infant mortality worldwide. A major obstacle in addressing PTB is that the mechanisms controlling parturition and birth timing remain poorly understood. Integrative approaches that overlay datasets derived from comparative genomics with function-derived ones have potential to advance our understanding of the genetics of birth timing, and thus provide insights into the genes that may contribute to PTB. We intersected data from fast evolving coding and non-coding gene regions in the human and primate lineage with data from genes expressed in the placenta, from genes that show enriched expression only in the placenta, as well as from genes that are differentially expressed in four distinct PTB clinical subtypes. A large fraction of genes that are expressed in placenta, and differentially expressed in PTB clinical subtypes (23–34%) are fast evolving, and are associated with functions that include adhesion neurodevelopmental and immune processes. Functional categories of genes that express fast evolution in coding regions differ from those linked to fast evolution in non-coding regions. Finally, there is a surprising lack of overlap between fast evolving genes that are differentially expressed in four PTB clinical subtypes. Integrative approaches, especially those that incorporate evolutionary perspectives, can be successful in identifying potential genetic contributions to complex genetic diseases, such as PTB.
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Affiliation(s)
- Jibril Hirbo
- Department of Biological Sciences, Vanderbilt University, Box 35164 Station B, Nashville, TN, 37235–1634, United States of America
| | - Haley Eidem
- Department of Biological Sciences, Vanderbilt University, Box 35164 Station B, Nashville, TN, 37235–1634, United States of America
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Box 35164 Station B, Nashville, TN, 37235–1634, United States of America
| | - Patrick Abbot
- Department of Biological Sciences, Vanderbilt University, Box 35164 Station B, Nashville, TN, 37235–1634, United States of America
- * E-mail:
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44
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Silver DL. Genomic divergence and brain evolution: How regulatory DNA influences development of the cerebral cortex. Bioessays 2015; 38:162-71. [PMID: 26642006 DOI: 10.1002/bies.201500108] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The cerebral cortex controls our most distinguishing higher cognitive functions. Human-specific gene expression differences are abundant in the cerebral cortex, yet we have only begun to understand how these variations impact brain function. This review discusses the current evidence linking non-coding regulatory DNA changes, including enhancers, with neocortical evolution. Functional interrogation using animal models reveals converging roles for our genome in key aspects of cortical development including progenitor cell cycle and neuronal signaling. New technologies, including iPS cells and organoids, offer potential alternatives to modeling evolutionary modifications in a relevant species context. Several diseases rooted in the cerebral cortex uniquely manifest in humans compared to other primates, thus highlighting the importance of understanding human brain differences. Future studies of regulatory loci, including those implicated in disease, will collectively help elucidate key cellular and genetic mechanisms underlying our distinguishing cognitive traits.
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Affiliation(s)
- Debra L Silver
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA.,Department of Cell Biology, Duke University Medical Center, Durham, NC, USA.,Department of Neurobiology, Duke University Medical Center, Durham, NC, USA.,Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC, USA
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45
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Franchini LF, Pollard KS. Genomic approaches to studying human-specific developmental traits. Development 2015; 142:3100-12. [DOI: 10.1242/dev.120048] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Changes in developmental regulatory programs drive both disease and phenotypic differences among species. Linking human-specific traits to alterations in development is challenging, because we have lacked the tools to assay and manipulate regulatory networks in human and primate embryonic cells. This field was transformed by the sequencing of hundreds of genomes – human and non-human – that can be compared to discover the regulatory machinery of genes involved in human development. This approach has identified thousands of human-specific genome alterations in developmental genes and their regulatory regions. With recent advances in stem cell techniques, genome engineering, and genomics, we can now test these sequences for effects on developmental gene regulation and downstream phenotypes in human cells and tissues.
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Affiliation(s)
- Lucía F. Franchini
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1428, Argentina
| | - Katherine S. Pollard
- Gladstone Institutes, San Francisco, CA 94158, USA
- Institute for Human Genetics, Department of Epidemiology & Biostatistics, University of California, San Francisco, CA 94158, USA
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46
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Ward M, McEwan C, Mills JD, Janitz M. Conservation and tissue-specific transcription patterns of long noncoding RNAs. ACTA ACUST UNITED AC 2015; 1:2-9. [PMID: 27335896 PMCID: PMC4894084 DOI: 10.3109/23324015.2015.1077591] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 07/15/2015] [Indexed: 12/31/2022]
Abstract
Over the past decade, the focus of molecular biology has shifted from being predominately DNA and protein-centric to having a greater appreciation of RNA. It is now accepted that the genome is pervasively transcribed in tissue- and cell-specific manner, to produce not only protein-coding RNAs, but also an array of noncoding RNAs (ncRNAs). Many of these ncRNAs have been found to interact with DNA, protein and other RNA molecules where they exert regulatory functions. Long ncRNAs (lncRNAs) are a subclass of ncRNAs that are particularly interesting due to their cell-specific and species-specific expression patterns and unique conservation patterns. Currently, individual lncRNAs have been classified functionally; however, for the vast majority the functional relevance is unknown. To better categorize lncRNAs, an understanding of their specific expression patterns and evolutionary constraints are needed.
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Affiliation(s)
- Melanie Ward
- School of Biotechnology and Biomolecular Sciences, University of New South Wales , Sydney, NSW 2052, Australia
| | - Callum McEwan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales , Sydney, NSW 2052, Australia
| | - James D Mills
- School of Biotechnology and Biomolecular Sciences, University of New South Wales , Sydney, NSW 2052, Australia
| | - Michael Janitz
- School of Biotechnology and Biomolecular Sciences, University of New South Wales , Sydney, NSW 2052, Australia
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47
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Kryuchkova-Mostacci N, Robinson-Rechavi M. Tissue-Specific Evolution of Protein Coding Genes in Human and Mouse. PLoS One 2015; 10:e0131673. [PMID: 26121354 PMCID: PMC4488272 DOI: 10.1371/journal.pone.0131673] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 06/04/2015] [Indexed: 12/23/2022] Open
Abstract
Protein-coding genes evolve at different rates, and the influence of different parameters, from gene size to expression level, has been extensively studied. While in yeast gene expression level is the major causal factor of gene evolutionary rate, the situation is more complex in animals. Here we investigate these relations further, especially taking in account gene expression in different organs as well as indirect correlations between parameters. We used RNA-seq data from two large datasets, covering 22 mouse tissues and 27 human tissues. Over all tissues, evolutionary rate only correlates weakly with levels and breadth of expression. The strongest explanatory factors of purifying selection are GC content, expression in many developmental stages, and expression in brain tissues. While the main component of evolutionary rate is purifying selection, we also find tissue-specific patterns for sites under neutral evolution and for positive selection. We observe fast evolution of genes expressed in testis, but also in other tissues, notably liver, which are explained by weak purifying selection rather than by positive selection.
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Affiliation(s)
- Nadezda Kryuchkova-Mostacci
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Marc Robinson-Rechavi
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
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48
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Climer S, Templeton AR, Zhang W. Human gephyrin is encompassed within giant functional noncoding yin-yang sequences. Nat Commun 2015; 6:6534. [PMID: 25813846 PMCID: PMC4380243 DOI: 10.1038/ncomms7534] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 02/06/2015] [Indexed: 12/31/2022] Open
Abstract
Gephyrin is a highly-conserved gene that is vital for the organization of proteins at inhibitory receptors, molybdenum cofactor biosynthesis, and other diverse functions. Its specific function is intricately regulated and its aberrant activities have been observed for a number of human diseases. Here we report a remarkable yin-yang haplotype pattern encompassing gephyrin. Yin-yang haplotypes arise when a stretch of DNA evolves to present two disparate forms that bear differing states for nucleotide variations along their lengths. The gephyrin yin-yang pair consists of 284 divergent nucleotide states and both variants vary drastically from their mutual ancestral haplotype, suggesting rapid evolution. Several independent lines of evidence indicate strong positive selection on the region and suggest these high-frequency haplotypes represent two distinct functional mechanisms. This discovery holds potential to deepen our understanding of variable human-specific regulation of gephyrin while providing clues for rapid evolutionary events and allelic migrations buried within human history.
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Affiliation(s)
- Sharlee Climer
- Department of Computer Science and Engineering, Washington University, St Louis, Missouri 63130, USA
| | - Alan R Templeton
- 1] Department of Biology, Washington University, St Louis, Missouri 63130, USA [2] Department of Genetics, Washington University, St Louis, Missouri 63110, USA [3] Department of Evolutionary and Environmental Biology, University of Haifa, Haifa 31905, Israel
| | - Weixiong Zhang
- 1] Department of Computer Science and Engineering, Washington University, St Louis, Missouri 63130, USA [2] Department of Genetics, Washington University, St Louis, Missouri 63110, USA [3] Institute for Systems Biology, Jianghan University, Wuhan, Hubei 430056, China
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49
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Boyd JL, Skove SL, Rouanet JP, Pilaz LJ, Bepler T, Gordân R, Wray GA, Silver DL. Human-chimpanzee differences in a FZD8 enhancer alter cell-cycle dynamics in the developing neocortex. Curr Biol 2015; 25:772-779. [PMID: 25702574 DOI: 10.1016/j.cub.2015.01.041] [Citation(s) in RCA: 170] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 08/28/2014] [Accepted: 01/16/2015] [Indexed: 12/14/2022]
Abstract
The human neocortex differs from that of other great apes in several notable regards, including altered cell cycle, prolonged corticogenesis, and increased size [1-5]. Although these evolutionary changes most likely contributed to the origin of distinctively human cognitive faculties, their genetic basis remains almost entirely unknown. Highly conserved non-coding regions showing rapid sequence changes along the human lineage are candidate loci for the development and evolution of uniquely human traits. Several studies have identified human-accelerated enhancers [6-14], but none have linked an expression difference to a specific organismal trait. Here we report the discovery of a human-accelerated regulatory enhancer (HARE5) of FZD8, a receptor of the Wnt pathway implicated in brain development and size [15, 16]. Using transgenic mice, we demonstrate dramatic differences in human and chimpanzee HARE5 activity, with human HARE5 driving early and robust expression at the onset of corticogenesis. Similar to HARE5 activity, FZD8 is expressed in neural progenitors of the developing neocortex [17-19]. Chromosome conformation capture assays reveal that HARE5 physically and specifically contacts the core Fzd8 promoter in the mouse embryonic neocortex. To assess the phenotypic consequences of HARE5 activity, we generated transgenic mice in which Fzd8 expression is under control of orthologous enhancers (Pt-HARE5::Fzd8 and Hs-HARE5::Fzd8). In comparison to Pt-HARE5::Fzd8, Hs-HARE5::Fzd8 mice showed marked acceleration of neural progenitor cell cycle and increased brain size. Changes in HARE5 function unique to humans thus alter the cell-cycle dynamics of a critical population of stem cells during corticogenesis and may underlie some distinctive anatomical features of the human brain.
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Affiliation(s)
- J Lomax Boyd
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Stephanie L Skove
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Jeremy P Rouanet
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Louis-Jan Pilaz
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Tristan Bepler
- Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
| | - Raluca Gordân
- Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA; Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, NC 27710, USA
| | - Gregory A Wray
- Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA; Department of Biology, Duke University, Durham, NC 27708, USA; Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA
| | - Debra L Silver
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Duke Institute for Brain Sciences, Durham, NC 27710 USA.
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50
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Necsulea A, Kaessmann H. Evolutionary dynamics of coding and non-coding transcriptomes. Nat Rev Genet 2014; 15:734-48. [PMID: 25297727 DOI: 10.1038/nrg3802] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Gene expression changes may underlie much of phenotypic evolution. The development of high-throughput RNA sequencing protocols has opened the door to unprecedented large-scale and cross-species transcriptome comparisons by allowing accurate and sensitive assessments of transcript sequences and expression levels. Here, we review the initial wave of the new generation of comparative transcriptomic studies in mammals and vertebrate outgroup species in the context of earlier work. Together with various large-scale genomic and epigenomic data, these studies have unveiled commonalities and differences in the dynamics of gene expression evolution for various types of coding and non-coding genes across mammalian lineages, organs, developmental stages, chromosomes and sexes. They have also provided intriguing new clues to the regulatory basis and phenotypic implications of evolutionary gene expression changes.
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Affiliation(s)
- Anamaria Necsulea
- Laboratory of Developmental Genomics, School of Life Sciences, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Henrik Kaessmann
- 1] Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland. [2] Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
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