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Premachandra T, Cauret CMS, Conradie W, Measey J, Evans BJ. Population genomics and subgenome evolution of the allotetraploid frog Xenopus laevis in southern Africa. G3 (BETHESDA, MD.) 2022; 13:6916838. [PMID: 36524354 PMCID: PMC9911082 DOI: 10.1093/g3journal/jkac325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 12/02/2022] [Accepted: 12/02/2022] [Indexed: 12/23/2022]
Abstract
Allotetraploid genomes have two distinct genomic components called subgenomes that are derived from separate diploid ancestral species. Many genomic characteristics such as gene function, expression, recombination, and transposable element mobility may differ significantly between subgenomes. To explore the possibility that subgenome population structure and gene flow may differ as well, we examined genetic variation in an allotetraploid frog-the African clawed frog (Xenopus laevis)-over the dynamic and varied habitat of its native range in southern Africa. Using reduced representation genome sequences from 91 samples from 12 localities, we found no strong evidence that population structure and gene flow differed substantially by subgenome. We then compared patterns of population structure in the nuclear genome to the mitochondrial genome using Sanger sequences from 455 samples from 183 localities. Our results provide further resolution to the geographic distribution of mitochondrial and nuclear diversity in this species and illustrate that population structure in both genomes corresponds roughly with variation in seasonal rainfall and with the topography of southern Africa.
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Affiliation(s)
- Tharindu Premachandra
- Department of Biology, McMaster University, Life Sciences Building Room 328, 1280 Main Street West, Hamilton, ON L8S4K1, Canada
| | - Caroline M S Cauret
- Department of Biology, McMaster University, Life Sciences Building Room 328, 1280 Main Street West, Hamilton, ON L8S4K1, Canada,Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
| | - Werner Conradie
- Port Elizabeth Museum (Bayworld), P.O. Box 13147, Humewood, Gqeberha 6013, South Africa,Department of Conservation Management, Natural Resource Science and Management Cluster, Faculty of Science, Nelson Mandela University, George Campus, George 6019, South Africa
| | - John Measey
- Corresponding author: Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Stellenbosch 7602, South Africa.
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Evans BJ, Mudd AB, Bredeson JV, Furman BLS, Wasonga DV, Lyons JB, Harland RM, Rokhsar DS. New insights into Xenopus sex chromosome genomics from the Marsabit clawed frog X. borealis. J Evol Biol 2022; 35:1777-1790. [PMID: 36054077 PMCID: PMC9722552 DOI: 10.1111/jeb.14078] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 06/23/2022] [Accepted: 07/14/2022] [Indexed: 11/26/2022]
Abstract
In many groups, sex chromosomes change frequently but the drivers of their rapid evolution are varied and often poorly characterized. With an aim of further understanding sex chromosome turnover, we investigated the polymorphic sex chromosomes of the Marsabit clawed frog, Xenopus borealis, using genomic data and a new chromosome-scale genome assembly. We confirmed previous findings that 54.1 Mb of chromosome 8L is sex-linked in animals from east Kenya and a laboratory strain, but most (or all) of this region is not sex-linked in natural populations from west Kenya. Previous work suggests possible degeneration of the Z chromosomes in the east population because many sex-linked transcripts of this female heterogametic population have female-biased expression, and we therefore expected this chromosome to not be present in the west population. In contrast, our simulations support a model where most or all of the sex-linked portion of the Z chromosome from the east acquired autosomal segregation in the west, and where much genetic variation specific to the large sex-linked portion of the W chromosome from the east is not present in the west. These recent changes are consistent with the hot-potato model, wherein sex chromosome turnover is favoured by natural selection if it purges a (minimally) degenerate sex-specific sex chromosome, but counterintuitively suggest natural selection failed to purge a Z chromosome that has signs of more advanced and possibly more ancient regulatory degeneration. These findings highlight complex evolutionary dynamics of young, rapidly evolving Xenopus sex chromosomes and set the stage for mechanistic work aimed at pinpointing additional sex-determining genes in this group.
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Affiliation(s)
- Ben J Evans
- Biology Department, Life Sciences Building Room 328, McMaster University, Hamilton, Ontario, Canada
| | - Austin B Mudd
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Jessen V Bredeson
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Benjamin L S Furman
- Biology Department, Life Sciences Building Room 328, McMaster University, Hamilton, Ontario, Canada
- Canexia Health, Vancouver, British Columbia, Canada
| | | | - Jessica B Lyons
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Richard M Harland
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Dan S Rokhsar
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
- Okinawa Institute of Science and Technology Graduate University, Onna, Japan
- Chan-Zuckerberg BioHub, San Francisco, California, USA
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Roco ÁS, Ruiz-García A, Bullejos M. Interaction between sex-determining genes from two species: clues from Xenopus hybrids. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200104. [PMID: 34304589 PMCID: PMC8310712 DOI: 10.1098/rstb.2020.0104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2020] [Indexed: 12/13/2022] Open
Abstract
Hybrids provide an interesting model to study the evolution of sex-determining genes and sex chromosome systems as they offer the opportunity to see how independently evolving sex-determining pathways interact in vivo. In this context, the genus Xenopus represents a stimulating model, since species with non-homologous sex chromosomes and different sex-determining genes have been identified. In addition, the possibility of interspecies breeding is favoured in this group, which arose by alloploidization events, with species ploidy ranging from 2n = 2x = 20 in X. tropicalis (the only diploid representative of the genus) to 2n = 12x = 108 in X. ruwenzoriensis. To study how two sex-determining genes interact in vivo, X. laevis × X. tropicalis hybrids were produced. Gonadal differentiation in these hybrids revealed that the dm-w gene is dominant over X. tropicalis male-determining sex chromosomes (Y or Z), even though the Y chromosome is dominant in X. tropicalis (Y > W>Z). In the absence of the dm-w gene (the Z chromosome from X. laevis is present), the W chromosome from X. tropicalis is able to trigger ovarian development. Testicular differentiation will take place in the absence of W chromosomes from any of the parental species. The dominance/recessivity relationships between these sex-determining loci in the context of either parental genome remains unknown. This article is part of the theme issue 'Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part II)'.
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Affiliation(s)
- Álvaro S. Roco
- Departamento de Biología Experimental, Facultad de Ciencias Experimentales, Universidad de Jaén, Campus Las Lagunillas S/N, 23071 Jaén, Spain
| | - Adrián Ruiz-García
- Departamento de Biología Experimental, Facultad de Ciencias Experimentales, Universidad de Jaén, Campus Las Lagunillas S/N, 23071 Jaén, Spain
| | - Mónica Bullejos
- Departamento de Biología Experimental, Facultad de Ciencias Experimentales, Universidad de Jaén, Campus Las Lagunillas S/N, 23071 Jaén, Spain
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Heterogeneity of synonymous substitution rates in the Xenopus frog genome. PLoS One 2020; 15:e0236515. [PMID: 32764757 PMCID: PMC7413554 DOI: 10.1371/journal.pone.0236515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/07/2020] [Indexed: 11/19/2022] Open
Abstract
With the increasing availability of high quality genomic data, there is opportunity to deeply explore the genealogical relationships of different gene loci between closely related species. In this study, we utilized genomes of Xenopus laevis (XLA, a tetraploid species with (L) and (S) sub-genomes) and X. tropicalis (XTR, a diploid species) to investigate whether synonymous substitution rates among orthologous or homoeologous genes displayed any heterogeneity. From over 1500 orthologous/homoeologous genes collected, we calculated proportion of synonymous substitutions between genomes/sub-genomes (k) and found variation within and between chromosomes. Within most chromosomes, we identified higher k with distance from the centromere, likely attributed to higher substitution rates and recombination in these regions. Using maximum likelihood methods, we identified further evidence supporting rate heterogeneity, and estimated species divergence times and ancestral population sizes. Estimated species divergence times (XLA.L-XLA.S: ~25.5 mya; XLA-XTR: ~33.0 mya) were slightly younger compared to a past study, attributed to consideration of population size in our study. Meanwhile, we found very large estimated population size in the ancestral populations of the two species (NA = 2.55 x 106). Local hybridization and population structure, which have not yet been well elucidated in frogs, may be a contributing factor to these possible large population sizes.
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Ackermann RR, Arnold ML, Baiz MD, Cahill JA, Cortés-Ortiz L, Evans BJ, Grant BR, Grant PR, Hallgrimsson B, Humphreys RA, Jolly CJ, Malukiewicz J, Percival CJ, Ritzman TB, Roos C, Roseman CC, Schroeder L, Smith FH, Warren KA, Wayne RK, Zinner D. Hybridization in human evolution: Insights from other organisms. Evol Anthropol 2019; 28:189-209. [PMID: 31222847 PMCID: PMC6980311 DOI: 10.1002/evan.21787] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 01/30/2019] [Accepted: 04/30/2019] [Indexed: 12/14/2022]
Abstract
During the late Pleistocene, isolated lineages of hominins exchanged genes thus influencing genomic variation in humans in both the past and present. However, the dynamics of this genetic exchange and associated phenotypic consequences through time remain poorly understood. Gene exchange across divergent lineages can result in myriad outcomes arising from these dynamics and the environmental conditions under which it occurs. Here we draw from our collective research across various organisms, illustrating some of the ways in which gene exchange can structure genomic/phenotypic diversity within/among species. We present a range of examples relevant to questions about the evolution of hominins. These examples are not meant to be exhaustive, but rather illustrative of the diverse evolutionary causes/consequences of hybridization, highlighting potential drivers of human evolution in the context of hybridization including: influences on adaptive evolution, climate change, developmental systems, sex-differences in behavior, Haldane's rule and the large X-effect, and transgressive phenotypic variation.
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Affiliation(s)
- Rebecca R. Ackermann
- Department of Archaeology, University of Cape Town, Rondebosch, South Africa
- Human Evolution Research Institute, University of Cape Town, Rondebosch, South Africa
| | | | - Marcella D. Baiz
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan
| | - James A. Cahill
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California
| | - Liliana Cortés-Ortiz
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan
| | - Ben J. Evans
- Biology Department, Life Sciences Building, McMaster University, Hamilton, Canada
| | - B. Rosemary Grant
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey
| | - Peter R. Grant
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey
| | - Benedikt Hallgrimsson
- Department of Cell Biology and Anatomy and the Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Robyn A. Humphreys
- Department of Archaeology, University of Cape Town, Rondebosch, South Africa
- Human Evolution Research Institute, University of Cape Town, Rondebosch, South Africa
| | - Clifford J. Jolly
- Center for the Study of Human Origins, Department of Anthropology, New York University, and NYCEP, New York, New York
| | - Joanna Malukiewicz
- Biodesign Institute, Arizona State University, Tempe, Arizona
- Federal University of Vicosa, Department of Animal Biology, Brazil
| | - Christopher J. Percival
- Department of Cell Biology and Anatomy and the Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Canada
- Department of Anthropology, Stony Brook University, New York
| | - Terrence B. Ritzman
- Department of Archaeology, University of Cape Town, Rondebosch, South Africa
- Human Evolution Research Institute, University of Cape Town, Rondebosch, South Africa
- Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri
- Department of Anthropology, Washington University, St. Louis, Missouri
| | - Christian Roos
- Primate Genetics Laboratory, German Primate Center (DPZ), Leibniz Institute for Primate Research, Göttingen, Germany
| | - Charles C. Roseman
- Department of Animal Biology, School of Integrative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Lauren Schroeder
- Human Evolution Research Institute, University of Cape Town, Rondebosch, South Africa
- Department of Anthropology, University of Toronto Mississauga, Mississauga, Canada
| | - Fred H. Smith
- Department of Sociology and Anthropology, Illinois State University, Normal, Illinois
| | - Kerryn A. Warren
- Department of Archaeology, University of Cape Town, Rondebosch, South Africa
- Human Evolution Research Institute, University of Cape Town, Rondebosch, South Africa
| | | | - Dietmar Zinner
- Cognitive Ethology Laboratory, German Primate Center (DPZ), Leibniz Institute for Primate Research, Göttingen, Germany
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De Villiers FA, Measey J. Overland movement in African clawed frogs ( Xenopus laevis): empirical dispersal data from within their native range. PeerJ 2017; 5:e4039. [PMID: 29134157 PMCID: PMC5683045 DOI: 10.7717/peerj.4039] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 10/24/2017] [Indexed: 11/20/2022] Open
Abstract
Dispersal forms are an important component of the ecology of many animals, and reach particular importance for predicting ranges of invasive species. African clawed frogs (Xenopus laevis) move overland between water bodies, but all empirical studies are from invasive populations with none from their native southern Africa. Here we report on incidents of overland movement found through a capture-recapture study carried out over a three year period in Overstrand, South Africa. The maximum distance moved was 2.4 km with most of the 91 animals, representing 5% of the population, moving ∼150 m. We found no differences in distances moved by males and females, despite the former being smaller. Fewer males moved overland, but this was no different from the sex bias found in the population. In laboratory performance trials, we found that males outperformed females, in both distance moved and time to exhaustion, when corrected for size. Overland movement occurred throughout the year, but reached peaks in spring and early summer when temporary water bodies were drying. Despite permanent impoundments being located within the study area, we found no evidence for migrations of animals between temporary and permanent water bodies. Our study provides the first dispersal kernel for X. laevis and suggests that it is similar to many non-pipid anurans with respect to dispersal.
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Affiliation(s)
- F André De Villiers
- Centre for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - John Measey
- Centre for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, Stellenbosch, South Africa
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