1
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Li H, Luo QP, Zhao S, Zhou YY, Huang FY, Yang XR, Su JQ. Effect of phenol formaldehyde-associated microplastics on soil microbial community, assembly, and functioning. JOURNAL OF HAZARDOUS MATERIALS 2023; 443:130288. [PMID: 36335899 DOI: 10.1016/j.jhazmat.2022.130288] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
Increasing investigations explore the effects of plastic pollutants on bacterial communities, diversity, and functioning in various ecosystems. However, the impact of microplastics (MPs) on the eukaryotic community, microbial assemblages, and interactions is still limited. Here, we investigated bacterial and micro-eukaryotic communities and functioning in soils with different concentrations of phenol formaldehyde-associated MPs (PF-MPs), and revealed the factors, such as soil properties, microbial community assembly, and interactions between microbes, influencing them. Our results showed that a high concentration (1%) of PF-MPs decreased the microbial interactions and the contribution of deterministic processes to the community assembly of microbes, and consequently changed the communities of bacteria, but not eukaryotes. A significant and negative relationship was determined between N2O emission rate and functional genes related to nitrification, indicating that the competitive interactions between functional microbes would affect the nitrogen cycling of soil ecosystem. We further found that vegetable biomass weakly decreased in treatments with a higher concentration of PF-MPs and positively related to the diversity of micro-eukaryotic communities and functional diversity of bacterial communities. These results suggest that a high concentration of the PF-MPs would influence crop growth by changing microbial communities, interactions, and eukaryotic and functional diversity. Our findings provide important evidence for agriculture management of phenol formaldehyde and suggest that we must consider their threats to microbial community compositions, diversity, and assemblage in soils due to the accumulation of PF-MPs widely used in the field.
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Affiliation(s)
- Hu Li
- Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo 315830, PR China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, PR China.
| | - Qiu-Ping Luo
- Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China
| | - Sha Zhao
- Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China
| | - Yan-Yan Zhou
- Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China
| | - Fu-Yi Huang
- Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China
| | - Xiao-Ru Yang
- Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo 315830, PR China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, PR China
| | - Jian-Qiang Su
- Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo 315830, PR China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, PR China.
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2
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Kariñho-Betancourt E, Carlson D, Hollister J, Fischer A, Greiner S, Johnson MTJ. The evolution of multi-gene families and metabolic pathways in the evening primroses (Oenothera: Onagraceae): A comparative transcriptomics approach. PLoS One 2022; 17:e0269307. [PMID: 35749399 PMCID: PMC9231714 DOI: 10.1371/journal.pone.0269307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Accepted: 05/18/2022] [Indexed: 12/02/2022] Open
Abstract
The plant genus Oenothera has played an important role in the study of plant evolution of genomes and plant defense and reproduction. Here, we build on the 1kp transcriptomic dataset by creating 44 new transcriptomes and analyzing a total of 63 transcriptomes to present a large-scale comparative study across 29 Oenothera species. Our dataset included 30.4 million reads per individual and 2.3 million transcripts on average. We used this transcriptome resource to examine genome-wide evolutionary patterns and functional diversification by searching for orthologous genes and performed gene family evolution analysis. We found wide heterogeneity in gene family evolution across the genus, with section Oenothera exhibiting the most pronounced evolutionary changes. Overall, more significant gene family expansions occurred than contractions. We also analyzed the molecular evolution of phenolic metabolism by retrieving proteins annotated for phenolic enzymatic complexes. We identified 1,568 phenolic genes arranged into 83 multigene families that varied widely across the genus. All taxa experienced rapid phenolic evolution (fast rate of genomic turnover) involving 33 gene families, which exhibited large expansions, gaining about 2-fold more genes than they lost. Upstream enzymes phenylalanine ammonia-lyase (PAL) and 4-coumaroyl: CoA ligase (4CL) accounted for most of the significant expansions and contractions. Our results suggest that adaptive and neutral evolutionary processes have contributed to Oenothera diversification and rapid gene family evolution.
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Affiliation(s)
- Eunice Kariñho-Betancourt
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
- * E-mail: (EKB); (MTJJ)
| | - David Carlson
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, New York, United States of America
| | - Jessie Hollister
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, New York, United States of America
| | - Axel Fischer
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Stephan Greiner
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Marc T. J. Johnson
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
- * E-mail: (EKB); (MTJJ)
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3
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Nunez JCB, Rong S, Damian-Serrano A, Burley JT, Elyanow RG, Ferranti DA, Neil KB, Glenner H, Rosenblad MA, Blomberg A, Johannesson K, Rand DM. Ecological Load and Balancing Selection in Circumboreal Barnacles. Mol Biol Evol 2021; 38:676-685. [PMID: 32898261 PMCID: PMC7826171 DOI: 10.1093/molbev/msaa227] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Acorn barnacle adults experience environmental heterogeneity at various spatial scales of their circumboreal habitat, raising the question of how adaptation to high environmental variability is maintained in the face of strong juvenile dispersal and mortality. Here, we show that 4% of genes in the barnacle genome experience balancing selection across the entire range of the species. Many of these genes harbor mutations maintained across 2 My of evolution between the Pacific and Atlantic oceans. These genes are involved in ion regulation, pain reception, and heat tolerance, functions which are essential in highly variable ecosystems. The data also reveal complex population structure within and between basins, driven by the trans-Arctic interchange and the last glaciation. Divergence between Atlantic and Pacific populations is high, foreshadowing the onset of allopatric speciation, and suggesting that balancing selection is strong enough to maintain functional variation for millions of years in the face of complex demography.
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Affiliation(s)
- Joaquin C B Nunez
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI
| | - Stephen Rong
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI.,Center for Computational Molecular Biology, Brown University, Providence, RI
| | | | - John T Burley
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI.,Institute at Brown for Environment and Society, Brown University, Providence, RI
| | - Rebecca G Elyanow
- Center for Computational Molecular Biology, Brown University, Providence, RI
| | - David A Ferranti
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI
| | - Kimberly B Neil
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI
| | - Henrik Glenner
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Magnus Alm Rosenblad
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundberg Laboratory, Göteborg, Sweden
| | - Anders Blomberg
- Department of Chemistry and Molecular Biology, University of Gothenburg, Lundberg Laboratory, Göteborg, Sweden
| | - Kerstin Johannesson
- Department of Marine Sciences, University of Gothenburg, Tjärnö Marine Laboratory, Strömstad, Sweden
| | - David M Rand
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI.,Center for Computational Molecular Biology, Brown University, Providence, RI
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4
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Rizzo C, Lo Giudice A. The Variety and Inscrutability of Polar Environments as a Resource of Biotechnologically Relevant Molecules. Microorganisms 2020; 8:microorganisms8091422. [PMID: 32947905 PMCID: PMC7564310 DOI: 10.3390/microorganisms8091422] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/11/2020] [Accepted: 09/14/2020] [Indexed: 11/16/2022] Open
Abstract
The application of an ever-increasing number of methodological approaches and tools is positively contributing to the development and yield of bioprospecting procedures. In this context, cold-adapted bacteria from polar environments are becoming more and more intriguing as valuable sources of novel biomolecules, with peculiar properties to be exploited in a number of biotechnological fields. This review aims at highlighting the biotechnological potentialities of bacteria from Arctic and Antarctic habitats, both biotic and abiotic. In addition to cold-enzymes, which have been intensively analysed, relevance is given to recent advances in the search for less investigated biomolecules, such as biosurfactants, exopolysaccharides and antibiotics.
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Affiliation(s)
- Carmen Rizzo
- Stazione Zoologica Anton Dohrn, Department Marine Biotechnology, National Institute of Biology, Villa Pace, Contrada Porticatello 29, 98167 Messina, Italy
- Correspondence:
| | - Angelina Lo Giudice
- Institute of Polar Sciences, National Research Council (CNR-ISP), Spianata San Raineri 86, 98122 Messina, Italy;
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5
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Biological Effects of Single-Nucleotide Polymorphisms in the Drosophila melanogaster Malic Enzyme Locus. Biochem Genet 2019; 58:129-156. [PMID: 31302799 DOI: 10.1007/s10528-019-09932-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 07/05/2019] [Indexed: 10/26/2022]
Abstract
A pair of amino acid polymorphisms within the Drosophila melanogaster Malic enzyme (Men) locus presents an interesting case of genetic variation that appears to be under selection. The two alleles at each site are biochemically distinct, but their biological effects are unknown. One polymorphic site is near the active site and the other is buried within the protein. Strikingly, in twelve different populations, the first polymorphism is always found at approximately a 50:50 allelic frequency, whereas the second polymorphism is always found at approximately 90:10. The consistency of the frequencies between populations suggests that the polymorphisms are under selection and it is possible that balancing selection is at play. We used 16 lines of flies to create the nine genotypes needed to quantify both effects of the polymorphic sites and possible genetic background effects, which we found to be widespread. The alleles at each site differ, but in different biochemical characteristics. The first site significantly influences MEN Km and Vmax, whereas the second site affects the Km and the Vmax/Km ratio (relative activity). Interestingly, the rarest allele is the most biochemically distinct. We also assayed three more distal phenotypes, triglyceride concentration, carbohydrate concentration, and longevity. In all cases, the phenotypes of the heterozygous genotypes are intermediate between those of the respective homozygotes suggesting that if balancing selection is maintaining the observed allele frequencies it is not through non-linear combinations of the biochemical phenotypes.
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6
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Saarman NP, Kober KM, Simison WB, Pogson GH. Sequence-Based Analysis of Thermal Adaptation and Protein Energy Landscapes in an Invasive Blue Mussel (Mytilus galloprovincialis). Genome Biol Evol 2018; 9:2739-2751. [PMID: 28985307 PMCID: PMC5647807 DOI: 10.1093/gbe/evx190] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2017] [Indexed: 12/12/2022] Open
Abstract
Adaptive responses to thermal stress in poikilotherms plays an important role in determining competitive ability and species distributions. Amino acid substitutions that affect protein stability and modify the thermal optima of orthologous proteins may be particularly important in this context. Here, we examine a set of 2,770 protein-coding genes to determine if proteins in a highly invasive heat tolerant blue mussel (Mytilus galloprovincialis) contain signals of adaptive increases in protein stability relative to orthologs in a more cold tolerant M. trossulus. Such thermal adaptations might help to explain, mechanistically, the success with which the invasive marine mussel M. galloprovincialis has displaced native species in contact zones in the eastern (California) and western (Japan) Pacific. We tested for stabilizing amino acid substitutions in warm tolerant M. galloprovincialis relative to cold tolerant M. trossulus with a generalized linear model that compares in silico estimates of recent changes in protein stability among closely related congeners. Fixed substitutions in M. galloprovincialis were 3,180.0 calories per mol per substitution more stabilizing at genes with both elevated dN/dS ratios and transcriptional responses to heat stress, and 705.8 calories per mol per substitution more stabilizing across all 2,770 loci investigated. Amino acid substitutions concentrated in a small number of genes were more stabilizing in M. galloprovincialis compared with cold tolerant M. trossulus. We also tested for, but did not find, enrichment of a priori GO terms in genes with elevated dN/dS ratios in M. galloprovincialis. This might indicate that selection for thermodynamic stability is generic across all lineages, and suggests that the high change in estimated protein stability that we observed in M. galloprovincialis is driven by selection for extra stabilizing substitutions, rather than by higher incidence of selection in a greater number of genes in this lineage. Nonetheless, our finding of more stabilizing amino acid changes in the warm adapted lineage is important because it suggests that adaption for thermal stability has contributed to M. galloprovincialis’ superior tolerance to heat stress, and that pairing tests for positive selection and tests for transcriptional response to heat stress can identify candidates of protein stability adaptation.
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Affiliation(s)
- Norah P Saarman
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz.,Department of Ecology and Evolutionary Biology, Yale University
| | - Kord M Kober
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz.,Department of Physiological Nursing, University of California, San Francisco.,Institute for Computational Health Sciences, University of California, San Francisco
| | - W Brian Simison
- Center for Comparative Genomics, California Academy of Sciences, San Francisco, California
| | - Grant H Pogson
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz
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7
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Somero GN. RNA thermosensors: how might animals exploit their regulatory potential? J Exp Biol 2018; 221:221/4/jeb162842. [DOI: 10.1242/jeb.162842] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
ABSTRACT
The secondary and tertiary orders of RNA structure are crucial for a suite of RNA-related functions, including regulation of translation, gene expression and RNA turnover. The temperature sensitivity of RNA secondary and tertiary structures is exploited by bacteria to fabricate RNA thermosensing systems that allow a rapid adaptive response to temperature change. RNA thermometers (RNATs) present in non-coding regions of certain mRNAs of pathogenic bacteria enable rapid upregulation of translation of virulence proteins when the temperature of the bacterium rises after entering a mammalian host. Rapid upregulation of translation of bacterial heat-shock proteins likewise is governed in part by RNATs. Turnover of mRNA may be regulated by temperature-sensitive RNA structures. Whereas the roles of temperature-sensitive RNA structures similar to RNATs in Eukarya and Archaea are largely unknown, there would appear to be a potential for all taxa to adaptively regulate their thermal physiology through exploitation of RNA-based thermosensory responses akin to those of bacteria. In animals, these responses might include regulation of translation of stress-induced proteins, alternative splicing of messenger RNA precursors, differential expression of allelic proteins, modulation of activities of small non-coding RNAs, regulation of mRNA turnover and control of RNA editing. New methods for predicting, detecting and experimentally modifying RNA secondary structure offer promising windows into these fascinating aspects of RNA biochemistry. Elucidating whether animals too have exploited the types of RNA thermosensing tools that are used so effectively by bacteria seems likely to provide exciting new insights into the mechanisms of evolutionary adaptation and acclimatization to temperature.
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Affiliation(s)
- George N. Somero
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
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8
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Suzuki G, Wang Y, Kubo K, Hirata E, Ohnuki S, Ohya Y. Global study of holistic morphological effectors in the budding yeast Saccharomyces cerevisiae. BMC Genomics 2018; 19:149. [PMID: 29458326 PMCID: PMC5819264 DOI: 10.1186/s12864-018-4526-z] [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] [Received: 08/22/2017] [Accepted: 02/05/2018] [Indexed: 11/16/2022] Open
Abstract
Background The size of the phenotypic effect of a gene has been thoroughly investigated in terms of fitness and specific morphological traits in the budding yeast Saccharomyces cerevisiae, but little is known about gross morphological abnormalities. Results We identified 1126 holistic morphological effectors that cause severe gross morphological abnormality when deleted, and 2241 specific morphological effectors with weak holistic effects but distinctive effects on yeast morphology. Holistic effectors fell into many gene function categories and acted as network hubs, affecting a large number of morphological traits, interacting with a large number of genes, and facilitating high protein expression. Holistic morphological abnormality was useful for estimating the importance of a gene to morphology. The contribution of gene importance to fitness and morphology could be used to efficiently classify genes into functional groups. Conclusion Holistic morphological abnormality can be used as a reproducible and reliable gene feature for high-dimensional morphological phenotyping. It can be used in many functional genomic applications. Electronic supplementary material The online version of this article (10.1186/s12864-018-4526-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Godai Suzuki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Bldg. FSB-101, 5-1-5 Kashiwanoha, Kashiwa, Chiba Prefecture, 277-8562, Japan
| | - Yang Wang
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Bldg. FSB-101, 5-1-5 Kashiwanoha, Kashiwa, Chiba Prefecture, 277-8562, Japan
| | - Karen Kubo
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Bldg. FSB-101, 5-1-5 Kashiwanoha, Kashiwa, Chiba Prefecture, 277-8562, Japan
| | - Eri Hirata
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Bldg. FSB-101, 5-1-5 Kashiwanoha, Kashiwa, Chiba Prefecture, 277-8562, Japan
| | - Shinsuke Ohnuki
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Bldg. FSB-101, 5-1-5 Kashiwanoha, Kashiwa, Chiba Prefecture, 277-8562, Japan
| | - Yoshikazu Ohya
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Bldg. FSB-101, 5-1-5 Kashiwanoha, Kashiwa, Chiba Prefecture, 277-8562, Japan. .,AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Bldg. Kashiwa Research Complex 2, 5-1-5 Kahiwanoha, Kashiwa, Chiba Prefecture, 277-8565, Japan.
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9
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Hubby and Lewontin on Protein Variation in Natural Populations: When Molecular Genetics Came to the Rescue of Population Genetics. Genetics 2017; 203:1497-503. [PMID: 27516612 DOI: 10.1534/genetics.115.185975] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The 1966 GENETICS papers by John Hubby and Richard Lewontin were a landmark in the study of genome-wide levels of variability. They used the technique of gel electrophoresis of enzymes and proteins to study variation in natural populations of Drosophila pseudoobscura, at a set of loci that had been chosen purely for technical convenience, without prior knowledge of their levels of variability. Together with the independent study of human populations by Harry Harris, this seminal study provided the first relatively unbiased picture of the extent of genetic variability in protein sequences within populations, revealing that many genes had surprisingly high levels of diversity. These papers stimulated a large research program that found similarly high electrophoretic variability in many different species and led to statistical tools for interpreting the data in terms of population genetics processes such as genetic drift, balancing and purifying selection, and the effects of selection on linked variants. The current use of whole-genome sequences in studies of variation is the direct descendant of this pioneering work.
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10
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Chen HY, Ma SL, Huang W, Ji L, Leung VHK, Jiang H, Yao X, Tang NLS. The mechanism of transactivation regulation due to polymorphic short tandem repeats (STRs) using IGF1 promoter as a model. Sci Rep 2016; 6:38225. [PMID: 27910883 PMCID: PMC5133613 DOI: 10.1038/srep38225] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 11/07/2016] [Indexed: 11/09/2022] Open
Abstract
Functional short tandem repeats (STR) are polymorphic in the population, and the number of repeats regulates the expression of nearby genes (known as expression STR, eSTR). STR in IGF1 promoter has been extensively studied for its association with IGF1 concentration in blood and various clinical traits and represents an important eSTR. We previously used an in-vitro luciferase reporter model to examine the interaction between STRs and SNPs in IGF1 promoter. Here, we further explored the mechanism how the number of repeats of the STR regulates gene transcription. An inverse correlation between the number of repeats and the extent of transactivation was found in a haplotype consisting of three promoter SNPs (C-STR-T-T). We showed that these adjacent SNPs located outside the STR were required for the STR to function as eSTR. The C allele of rs35767 provides a binding site for CCAAT/enhancer-binding-protein δ (C/EBPD), which is essential for the gradational transactivation property of eSTR and FOXA3 may also be involved. Therefore, we propose a mechanism in which the gradational transactivation by the eSTR is caused by the interaction of one or more transcriptional complexes located outside the STR, rather than by direct binding to a repeat motif of the STR.
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Affiliation(s)
- Holly Y Chen
- Department of Chemical Pathology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Suk Ling Ma
- Department of Psychiatry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Wei Huang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Department of Pharmaceutics, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lindan Ji
- Department of Biochemistry and Molecular Biology, Zhejiang Provincial Key Laboratory of Pathophysiology, Ningbo University School of Medicine, Ningbo, China
| | - Vincent H K Leung
- Department of Chemical Pathology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Honglin Jiang
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
| | - Xiaoqiang Yao
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Nelson L S Tang
- Department of Chemical Pathology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.,School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Laboratory of Genetics of Disease Susceptibility, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.,Functional Genomics and Biostatistical Computing laboratory, Shenzhen Research Institute, The Chinese University of Hong Kong, China.,KIZ/CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming, China
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11
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Eanes WF. New views on the selection acting on genetic polymorphism in central metabolic genes. Ann N Y Acad Sci 2016; 1389:108-123. [PMID: 27859384 DOI: 10.1111/nyas.13285] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 09/20/2016] [Accepted: 09/29/2016] [Indexed: 12/14/2022]
Abstract
Studies of the polymorphism of central metabolic genes as a source of fitness variation in natural populations date back to the discovery of allozymes in the 1960s. The unique features of these genes and their enzymes and our knowledge base greatly facilitates the systems-level study of this group. The expectation that pathway flux control is central to understanding the molecular evolution of genes is discussed, as well as studies that attempt to place gene-specific molecular evolution and polymorphism into a context of pathway and network architecture. There is an increasingly complex picture of the metabolic genes assuming additional roles beyond their textbook anabolic and catabolic reactions. In particular, this review emphasizes the potential role of these genes as part of the energy-sensing machinery. It is underscored that the concentrations of key cellular metabolites are the reflections of cellular energy status and nutritional input. These metabolites are the top-down signaling messengers that set signaling through signaling pathways that are involved in energy economy. I propose that the polymorphisms in central metabolic genes shift metabolite concentrations and in that fashion act as genetic modifiers of the energy-state coupling to the transcriptional networks that affect physiological trade-offs with significant fitness consequences.
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Affiliation(s)
- Walter F Eanes
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, New York
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12
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Novelletto A, Testa L, Iacovelli F, Blasi P, Garofalo L, Mingozzi T, Falconi M. Polymorphism in Mitochondrial Coding Regions of Mediterranean Loggerhead Turtles: Evolutionary Relevance and Structural Effects. Physiol Biochem Zool 2016; 89:473-486. [DOI: 10.1086/688679] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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13
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Quibod IL, Perez-Quintero A, Booher NJ, Dossa GS, Grande G, Szurek B, Vera Cruz C, Bogdanove AJ, Oliva R. Effector Diversification Contributes to Xanthomonas oryzae pv. oryzae Phenotypic Adaptation in a Semi-Isolated Environment. Sci Rep 2016; 6:34137. [PMID: 27667260 PMCID: PMC5035989 DOI: 10.1038/srep34137] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 09/07/2016] [Indexed: 01/01/2023] Open
Abstract
Understanding the processes that shaped contemporary pathogen populations in agricultural landscapes is quite important to define appropriate management strategies and to support crop improvement efforts. Here, we took advantage of an historical record to examine the adaptation pathway of the rice pathogen Xanthomonas oryzae pv. oryzae (Xoo) in a semi-isolated environment represented in the Philippine archipelago. By comparing genomes of key Xoo groups we showed that modern populations derived from three Asian lineages. We also showed that diversification of virulence factors occurred within each lineage, most likely driven by host adaptation, and it was essential to shape contemporary pathogen races. This finding is particularly important because it expands our understanding of pathogen adaptation to modern agriculture.
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Affiliation(s)
- Ian Lorenzo Quibod
- Genetics and Biotechnology Division, International Rice Research Institute, Los Baños, Philippines
| | - Alvaro Perez-Quintero
- Résistance des Plantes aux Bioagresseurs, Institut de Recherche pour le Développement, Montpellier, France
| | - Nicholas J Booher
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York, USA
| | - Gerbert S Dossa
- Genetics and Biotechnology Division, International Rice Research Institute, Los Baños, Philippines
| | - Genelou Grande
- Genetics and Biotechnology Division, International Rice Research Institute, Los Baños, Philippines
| | - Boris Szurek
- Résistance des Plantes aux Bioagresseurs, Institut de Recherche pour le Développement, Montpellier, France
| | - Casiana Vera Cruz
- Genetics and Biotechnology Division, International Rice Research Institute, Los Baños, Philippines
| | - Adam J Bogdanove
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York, USA
| | - Ricardo Oliva
- Genetics and Biotechnology Division, International Rice Research Institute, Los Baños, Philippines
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Záhorská E. Climate warming and invasive fish species: Will they replace native fish species in waters of temperate zones? Biologia (Bratisl) 2016. [DOI: 10.1515/biolog-2016-0101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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15
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Van Belleghem SM, Roelofs D, Hendrickx F. Evolutionary history of a dispersal-associated locus across sympatric and allopatric divergent populations of a wing-polymorphic beetle across Atlantic Europe. Mol Ecol 2015; 24:890-908. [PMID: 25470210 DOI: 10.1111/mec.13031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 11/20/2014] [Accepted: 11/28/2014] [Indexed: 11/24/2022]
Abstract
Studying the evolutionary history of trait divergence, in particular those related to dispersal capacity, is of major interest for the process of local adaptation and metapopulation dynamics. Here, we reconstruct the evolution of different alleles at the nuclear-encoded mitochondrial NADP(+)-dependent isocitrate dehydrogenase (mtIdh) locus of the ground beetle Pogonus chalceus that are differentially and repeatedly selected in short- and long-winged populations in response to different hydrological regimes at both allopatric and sympatric scales along the Atlantic European coasts. We sequenced 2788 bp of the mtIdh locus spanning a ~7-kb genome region and compared its variation with that of two supposedly neutral genes. mtIdh sequences show (i) monophyletic clustering of the short-winged associated mtIDH-DE haplotypes within the long-winged associated mtIDH-AB haplotypes, (ii) a more than tenfold lower haplotype diversity associated with the mtIDH-DE alleles compared to the mtIDH-AB alleles and (iii) a high number of fixed nucleotide differences between both mtIDH haplotype clusters. Coalescent simulations suggest that this observed sequence variation in the mtIdh locus is most consistent with a singular origin in a partially isolated subpopulation, followed by a relatively recent spread of the mtIDH-DE allele in short-winged populations along the Atlantic coast. These results demonstrate that even traits associated with decreased dispersal capacity can rapidly spread and that reuse of adaptive alleles plays an important role in the adaptive potential within this sympatric mosaic of P. chalceus populations.
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Affiliation(s)
- Steven M Van Belleghem
- Terrestrial Ecology Unit, Biology Department, Ghent University, K. L. Ledeganckstraat 35, B-9000, Gent, Belgium; Royal Belgian Institute of Natural Sciences, Vautierstraat 29, 1000, Brussel, Belgium
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16
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Sellis D, Longo MD. Patterns of variation during adaptation in functionally linked loci. Evolution 2014; 69:75-89. [PMID: 25338665 DOI: 10.1111/evo.12548] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 09/04/2014] [Indexed: 11/27/2022]
Abstract
An understanding of the distribution of natural patterns of genetic variation is relevant to such fundamental biological fields as evolution and development. One recent approach to understanding such patterns has been to focus on the constraints that may arise as a function of the network or pathway context in which genes are embedded. Despite theoretical expectations of higher evolutionary constraint for genes encoding upstream versus downstream enzymes in metabolic pathways, empirical results have varied. Here we combine two complementary models from population genetics and enzyme kinetics to explore genetic variation as a function of pathway position when selection acts on whole-pathway flux. We are able to qualitatively reproduce empirically observed patterns of polymorphism and divergence and suggest that expectations should vary depending on the evolutionary trajectory of a population. Upstream genes are initially more polymorphic and diverge faster after an environmental change, while we see the opposite trend as the population approaches its fitness optimum.
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Affiliation(s)
- Diamantis Sellis
- Department of Biology, Stanford University, Stanford, California, 94305.
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Hybrid incompatibility arises in a sequence-based bioenergetic model of transcription factor binding. Genetics 2014; 198:1155-66. [PMID: 25173845 DOI: 10.1534/genetics.114.168112] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Postzygotic isolation between incipient species results from the accumulation of incompatibilities that arise as a consequence of genetic divergence. When phenotypes are determined by regulatory interactions, hybrid incompatibility can evolve even as a consequence of parallel adaptation in parental populations because interacting genes can produce the same phenotype through incompatible allelic combinations. We explore the evolutionary conditions that promote and constrain hybrid incompatibility in regulatory networks using a bioenergetic model (combining thermodynamics and kinetics) of transcriptional regulation, considering the bioenergetic basis of molecular interactions between transcription factors (TFs) and their binding sites. The bioenergetic parameters consider the free energy of formation of the bond between the TF and its binding site and the availability of TFs in the intracellular environment. Together these determine fractional occupancy of the TF on the promoter site, the degree of subsequent gene expression and in diploids, and the degree of dominance among allelic interactions. This results in a sigmoid genotype-phenotype map and fitness landscape, with the details of the shape determining the degree of bioenergetic evolutionary constraint on hybrid incompatibility. Using individual-based simulations, we subjected two allopatric populations to parallel directional or stabilizing selection. Misregulation of hybrid gene expression occurred under either type of selection, although it evolved faster under directional selection. Under directional selection, the extent of hybrid incompatibility increased with the slope of the genotype-phenotype map near the derived parental expression level. Under stabilizing selection, hybrid incompatibility arose from compensatory mutations and was greater when the bioenergetic properties of the interaction caused the space of nearly neutral genotypes around the stable expression level to be wide. F2's showed higher hybrid incompatibility than F1's to the extent that the bioenergetic properties favored dominant regulatory interactions. The present model is a mechanistically explicit case of the Bateson-Dobzhansky-Muller model, connecting environmental selective pressure to hybrid incompatibility through the molecular mechanism of regulatory divergence. The bioenergetic parameters that determine expression represent measurable properties of transcriptional regulation, providing a predictive framework for empirical studies of how phenotypic evolution results in epistatic incompatibility at the molecular level in hybrids.
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Purification and characterization of 6-phosphogluconate dehydrogenase from the wing-polymorphic cricket, Gryllus firmus , and assessment of causes of morph-differences in enzyme activity. Comp Biochem Physiol B Biochem Mol Biol 2014; 172-173:29-38. [DOI: 10.1016/j.cbpb.2014.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 03/27/2014] [Accepted: 04/01/2014] [Indexed: 11/21/2022]
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Mapping the fitness landscape of gene expression uncovers the cause of antagonism and sign epistasis between adaptive mutations. PLoS Genet 2014; 10:e1004149. [PMID: 24586190 PMCID: PMC3937219 DOI: 10.1371/journal.pgen.1004149] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 12/16/2013] [Indexed: 11/19/2022] Open
Abstract
How do adapting populations navigate the tensions between the costs of gene expression and the benefits of gene products to optimize the levels of many genes at once? Here we combined independently-arising beneficial mutations that altered enzyme levels in the central metabolism of Methylobacterium extorquens to uncover the fitness landscape defined by gene expression levels. We found strong antagonism and sign epistasis between these beneficial mutations. Mutations with the largest individual benefit interacted the most antagonistically with other mutations, a trend we also uncovered through analyses of datasets from other model systems. However, these beneficial mutations interacted multiplicatively (i.e., no epistasis) at the level of enzyme expression. By generating a model that predicts fitness from enzyme levels we could explain the observed sign epistasis as a result of overshooting the optimum defined by a balance between enzyme catalysis benefits and fitness costs. Knowledge of the phenotypic landscape also illuminated that, although the fitness peak was phenotypically far from the ancestral state, it was not genetically distant. Single beneficial mutations jumped straight toward the global optimum rather than being constrained to change the expression phenotypes in the correlated fashion expected by the genetic architecture. Given that adaptation in nature often results from optimizing gene expression, these conclusions can be widely applicable to other organisms and selective conditions. Poor interactions between individually beneficial alleles affecting gene expression may thus compromise the benefit of sex during adaptation and promote genetic differentiation. The pace and outcome of a series of adaptive steps in an evolving lineage depends upon how well different beneficial mutations stack on top of each other. We found that independent beneficial mutations that affected gene expression for a metabolic pathway did not work well together, and were often jointly deleterious. The most beneficial mutations interacted the most poorly with others, which was a trend we found common in other biological systems. Through generating a model that accounted for enzymatic benefits and expression costs, we uncovered that this antagonism was caused by a phenotype to fitness mapping that had an intermediate peak. This allowed us to predict the fitness effect of double mutants and to uncover that the single winning mutations tended to move straight to the peak in a single step. These findings demonstrate the importance of considering the phenotypic changes that cause nonlinear interactions between mutations upon fitness, and thus influence how populations evolve.
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Light SH, Minasov G, Duban ME, Anderson WF. Adherence to Bürgi-Dunitz stereochemical principles requires significant structural rearrangements in Schiff-base formation: insights from transaldolase complexes. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:544-52. [PMID: 24531488 PMCID: PMC3940192 DOI: 10.1107/s1399004713030666] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 11/08/2013] [Indexed: 11/10/2022]
Abstract
The Bürgi-Dunitz angle (αBD) describes the trajectory of approach of a nucleophile to an electrophile. The adoption of a stereoelectronically favorable αBD can necessitate significant reactive-group repositioning over the course of bond formation. In the context of enzyme catalysis, interactions with the protein constrain substrate rotation, which could necessitate structural transformations during bond formation. To probe this theoretical framework vis-à-vis biocatalysis, Schiff-base formation was analysed in Francisella tularensis transaldolase (TAL). Crystal structures of wild-type and Lys→Met mutant TAL in covalent and noncovalent complexes with fructose 6-phosphate and sedoheptulose 7-phosphate clarify the mechanism of catalysis and reveal that substrate keto moieties undergo significant conformational changes during Schiff-base formation. Structural changes compelled by the trajectory considerations discussed here bear relevance to bond formation in a variety of constrained enzymic/engineered systems and can inform the design of covalent therapeutics.
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Affiliation(s)
- Samuel H. Light
- Center for Structural Genomics of Infectious Diseases, USA
- Department of Molecular Pharmacology and Biological Chemistry, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - George Minasov
- Center for Structural Genomics of Infectious Diseases, USA
- Department of Molecular Pharmacology and Biological Chemistry, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Mark-Eugene Duban
- Center for Structural Genomics of Infectious Diseases, USA
- Department of Chemistry and Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, IL 60201, USA
| | - Wayne F. Anderson
- Center for Structural Genomics of Infectious Diseases, USA
- Department of Molecular Pharmacology and Biological Chemistry, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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Marden JH. Nature's inordinate fondness for metabolic enzymes: why metabolic enzyme loci are so frequently targets of selection. Mol Ecol 2013; 22:5743-64. [PMID: 24106889 DOI: 10.1111/mec.12534] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 09/11/2013] [Accepted: 09/17/2013] [Indexed: 01/01/2023]
Abstract
Metabolic enzyme loci were some of the first genes accessible for molecular evolution and ecology research. New technologies now make the whole genome, transcriptome or proteome readily accessible, allowing unbiased scans for loci exhibiting significant differences in allele frequency or expression level and associated with phenotypes and/or responses to natural selection. With surprising frequency and in many cases in proportions greater than chance relative to other genes, glycolysis and TCA cycle enzyme loci appear among the genes with significant associations in these studies. Hence, there is an ongoing need to understand the basis for fitness effects of metabolic enzyme polymorphisms. Allele-specific effects on the binding affinity and catalytic rate of individual enzymes are well known, but often of uncertain significance because metabolic control theory and in vivo studies indicate that many individual metabolic enzymes do not affect pathway flux rate. I review research, so far little used in evolutionary biology, showing that metabolic enzyme substrates affect signalling pathways that regulate cell and organismal biology, and that these enzymes have moonlighting functions. To date there is little knowledge of how alleles in natural populations affect these phenotypes. I discuss an example in which alleles of a TCA enzyme locus associate with differences in a signalling pathway and development, organismal performance, and ecological dynamics. Ultimately, understanding how metabolic enzyme polymorphisms map to phenotypes and fitness remains a compelling and ongoing need for gaining robust knowledge of ecological and evolutionary processes.
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Affiliation(s)
- James H Marden
- Department of Biology, Pennsylvania State University, University Park, PA, 16802, USA
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Evolution of tryptophan biosynthetic pathway in microbial genomes: a comparative genetic study. SYSTEMS AND SYNTHETIC BIOLOGY 2013; 8:59-72. [PMID: 24592292 DOI: 10.1007/s11693-013-9127-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 10/05/2013] [Accepted: 10/08/2013] [Indexed: 10/26/2022]
Abstract
Biosynthetic pathway evolution needs to consider the evolution of a group of genes that code for enzymes catalysing the multiple chemical reaction steps leading to the final end product. Tryptophan biosynthetic pathway has five chemical reaction steps that are highly conserved in diverse microbial genomes, though the genes of the pathway enzymes show considerable variations in arrangements, operon structure (gene fusion and splitting) and regulation. We use a combined bioinformatic and statistical analyses approach to address the question if the pathway genes from different microbial genomes, belonging to a wide range of groups, show similar evolutionary relationships within and between them. Our analyses involved detailed study of gene organization (fusion/splitting events), base composition, relative synonymous codon usage pattern of the genes, gene expressivity, amino acid usage, etc. to assess inter- and intra-genic variations, between and within the pathway genes, in diverse group of microorganisms. We describe these genetic and genomic variations in the tryptophan pathway genes in different microorganisms to show the similarities across organisms, and compare the same genes across different organisms to find the possible variability arising possibly due to horizontal gene transfers. Such studies form the basis for moving from single gene evolution to pathway evolutionary studies that are important steps towards understanding the systems biology of intracellular pathways.
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Dunning LT, Dennis AB, Thomson G, Sinclair BJ, Newcomb RD, Buckley TR. Positive selection in glycolysis among Australasian stick insects. BMC Evol Biol 2013; 13:215. [PMID: 24079656 PMCID: PMC3850572 DOI: 10.1186/1471-2148-13-215] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 09/23/2013] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND The glycolytic pathway is central to cellular energy production. Selection on individual enzymes within glycolysis, particularly phosphoglucose isomerase (Pgi), has been associated with metabolic performance in numerous organisms. Nonetheless, how whole energy-producing pathways evolve to allow organisms to thrive in different environments and adopt new lifestyles remains little explored. The Lanceocercata radiation of Australasian stick insects includes transitions from tropical to temperate climates, lowland to alpine habitats, and winged to wingless forms. This permits a broad investigation to determine which steps within glycolysis and what sites within enzymes are the targets of positive selection. To address these questions we obtained transcript sequences from seven core glycolysis enzymes, including two Pgi paralogues, from 29 Lanceocercata species. RESULTS Using maximum likelihood methods a signature of positive selection was inferred in two core glycolysis enzymes. Pgi and Glyceraldehyde 3-phosphate dehydrogenase (Gaphd) genes both encode enzymes linking glycolysis to the pentose phosphate pathway. Positive selection among Pgi paralogues and orthologues predominately targets amino acids with residues exposed to the protein's surface, where changes in physical properties may alter enzyme performance. CONCLUSION Our results suggest that, for Lancerocercata stick insects, adaptation to new stressful lifestyles requires a balance between maintaining cellular energy production, efficiently exploiting different energy storage pools and compensating for stress-induced oxidative damage.
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Affiliation(s)
- Luke T Dunning
- Landcare Research, Private Bag 92170, Auckland, New Zealand
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Allan Wilson Centre for Molecular Ecology and Evolution, Auckland, New Zealand
- Imperial College London, Silwood Park Campus, Buckhurst Road, SL5 7PY, Ascot, Berks, UK
| | - Alice B Dennis
- Landcare Research, Private Bag 92170, Auckland, New Zealand
- Allan Wilson Centre for Molecular Ecology and Evolution, Auckland, New Zealand
| | - Geoffrey Thomson
- Landcare Research, Private Bag 92170, Auckland, New Zealand
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Brent J Sinclair
- Department of Biology, The University of Western Ontario, London, ON, Canada N6G 1L3
| | - Richard D Newcomb
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Allan Wilson Centre for Molecular Ecology and Evolution, Auckland, New Zealand
- The New Zealand Institute for Plant & Food Research Limited, Auckland, New Zealand
| | - Thomas R Buckley
- Landcare Research, Private Bag 92170, Auckland, New Zealand
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Allan Wilson Centre for Molecular Ecology and Evolution, Auckland, New Zealand
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Han JC, Jo Q, Park YC, Park TG, Lee DC, Cho KC. A report on the mass summer mortalities of the farmed Pacific oysters, Crassostrea gigas and Bay scallops Argopecten irradians in the local waters of Goseong Bay, Korea. ACTA ACUST UNITED AC 2013. [DOI: 10.9710/kjm.2013.29.3.239] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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25
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Watt WB. Specific-gene studies of evolutionary mechanisms in an age of genome-wide surveying. Ann N Y Acad Sci 2013; 1289:1-17. [PMID: 23679204 DOI: 10.1111/nyas.12139] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The molecular tools of genomics have great power to reveal patterns of genetic difference within or among species, but must be complemented by the mechanistic study of the genetic variants found if these variants' evolutionary meaning is to be well understood. Central to this purpose is knowledge of the organisms' genotype-phenotype-environment interactions, which embody biological adaptation and constraint and thus drive natural selection. The history of this approach is briefly reviewed. Strategies embracing the complementarity of genomics and specific-gene studies in evolution are considered. Implementation of these strategies, and examples showing their feasibility and power, are discussed. Initial generalizations emphasize: (1) reproducibility of adaptive mechanisms; (2) evolutionary co-importance of variation in protein sequences and expression; (3) refinement of rudimentary molecular functions as an origin of evolutionary innovations; (4) identification of specific-gene mechanisms as underpinnings of genomic or quantitative genetic variation; and (5) multiple forms of adaptive or constraining epistasis among genes. Progress along these lines will advance understanding of evolution and support its use in addressing urgent medical and environmental applications.
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Affiliation(s)
- Ward B Watt
- Department of Biology, Stanford University, Stanford, California and Rocky Mountain Biological Laboratory, Crested Butte, Colorado, USA.
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Watt WB, Hudson RR, Wang B, Wang E. A genetic polymorphism evolving in parallel in two cell compartments and in two clades. BMC Evol Biol 2013; 13:9. [PMID: 23311980 PMCID: PMC3556304 DOI: 10.1186/1471-2148-13-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 12/12/2012] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The enzyme phosphoenolpyruvate carboxykinase, PEPCK, occurs in its guanosine-nucleotide-using form in animals and a few prokaryotes. We study its natural genetic variation in Colias (Lepidoptera, Pieridae). PEPCK offers a route, alternative to pyruvate kinase, for carbon skeletons to move between cytosolic glycolysis and mitochondrial Krebs cycle reactions. RESULTS PEPCK is expressed in both cytosol and mitochondrion, but differently in diverse animal clades. In vertebrates and independently in Drosophila, compartment-specific paralogous genes occur. In a contrasting expression strategy, compartment-specific PEPCKs of Colias and of the silkmoth, Bombyx, differ only in their first, 5', exons; these are alternatively spliced onto a common series of following exons. In two Colias species from distinct clades, PEPCK sequence is highly variable at nonsynonymous and synonymous sites, mainly in its common exons. Three major amino acid polymorphisms, Gly 335 ↔ Ser, Asp 503 ↔ Glu, and Ile 629 ↔ Val occur in both species, and in the first two cases are similar in frequency between species. Homology-based structural modelling shows that the variants can alter hydrogen bonding, salt bridging, or van der Waals interactions of amino acid side chains, locally or at one another's sites which are distant in PEPCK's structure, and thus may affect its enzyme function. We ask, using coalescent simulations, if these polymorphisms' cross-species similarities are compatible with neutral evolution by genetic drift, but find the probability of this null hypothesis is 0.001 ≤ P ≤ 0.006 under differing scenarios. CONCLUSION Our results make the null hypothesis of neutrality of these PEPCK polymorphisms quite unlikely, but support an alternative hypothesis that they are maintained by natural selection in parallel in the two species. This alternative can now be justifiably tested further via studies of PEPCK genotypes' effects on function, organismal performance, and fitness. This case emphasizes the importance, for evolutionary insight, of studying gene-specific mechanisms affected by natural genetic variation as an essential complement to surveys of such variation.
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Affiliation(s)
- Ward B Watt
- Department of Biology, Stanford University, Stanford, CA 94305-5020, USA
- Rocky Mountain Biological Laboratory, Crested Butte, CO 81224, USA
| | - Richard R Hudson
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, 60637, USA
| | - Baiqing Wang
- Department of Biology, Stanford University, Stanford, CA 94305-5020, USA
| | - Eddie Wang
- Department of Biology, Stanford University, Stanford, CA 94305-5020, USA
- Present address: Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, 0213, USA
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Miller SR, McGuirl MA, Carvey D. The Evolution of RuBisCO Stability at the Thermal Limit of Photoautotrophy. Mol Biol Evol 2013; 30:752-60. [DOI: 10.1093/molbev/mss327] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Olson-Manning CF, Lee CR, Rausher MD, Mitchell-Olds T. Evolution of flux control in the glucosinolate pathway in Arabidopsis thaliana. Mol Biol Evol 2013; 30:14-23. [PMID: 22923463 PMCID: PMC3525143 DOI: 10.1093/molbev/mss204] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Network characteristics of biochemical pathways are believed to influence the rate of evolutionary change in constituent enzymes. One characteristic that may affect rate heterogeneity is control of the amount of product produced by a biochemical pathway or flux control. In particular, theoretical analyses suggest that adaptive substitutions should be concentrated in the enzyme(s) that exert the greatest control over flux. Although a handful of studies have found a correlation between position in a pathway and evolutionary rate, these investigations have not examined the relationship between evolutionary rate and flux control. Given that genes with greater control will experience stronger selection and that the probability of fixation is proportional to the selective advantage, we ask the following: 1) do upstream enzymes have majority flux control, 2) do enzymes with majority flux control accumulate adaptive substitutions, and 3) are upstream enzymes under higher selective constraint? First, by perturbing the enzymes in the aliphatic glucosinolate pathway in Arabidopsis thaliana with gene insertion lines, we show that flux control is focused in the first enzyme in the pathway. Next, by analyzing several sequence signatures of selection, we also show that this enzyme is the only one in the pathway that shows convincing evidence of selection. Our results support the hypothesis that natural selection preferentially acts on enzymes with high flux control.
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Alvarez-Ponce D. The relationship between the hierarchical position of proteins in the human signal transduction network and their rate of evolution. BMC Evol Biol 2012; 12:192. [PMID: 23020283 PMCID: PMC3527147 DOI: 10.1186/1471-2148-12-192] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 09/14/2012] [Indexed: 11/23/2022] Open
Abstract
Background Proteins evolve at disparate rates, as a result of the action of different types and strengths of evolutionary forces. An open question in evolutionary biology is what factors are responsible for this variability. In general, proteins whose function has a great impact on organisms’ fitness are expected to evolve under stronger selective pressures. In biosynthetic pathways, upstream genes usually evolve under higher levels of selective constraint than those acting at the downstream part, as a result of their higher hierarchical position. Similar observations have been made in transcriptional regulatory networks, whose upstream elements appear to be more essential and subject to selection. Less well understood is, however, how selective pressures distribute along signal transduction pathways. Results Here, I combine comparative genomics and directed protein interaction data to study the distribution of evolutionary forces across the human signal transduction network. Surprisingly, no evidence was found for higher levels of selective constraint at the upstream network genes (those occupying more hierarchical positions). On the contrary, purifying selection was found to act more strongly on genes acting at the downstream part of the network, which seems to be due to downstream genes being more highly and broadly expressed, performing certain functions and, in particular, encoding proteins that are more highly connected in the protein–protein interaction network. When the effect of these confounding factors is discounted, upstream and downstream genes evolve at similar rates. The trends found in the overall signaling network are exemplified by analysis of the distribution of purifying selection along the mammalian Ras signaling pathway, showing that upstream and downstream genes evolve at similar rates. Conclusions These results indicate that the upstream/downstream position of proteins in the signal transduction network has, in general, no direct effect on their rates of evolution, suggesting that upstream and downstream genes are similarly important for the function of the network. This implies that natural selection differently distributes across signal transduction networks and across biosynthetic and transcriptional regulatory networks, which might reflect fundamental differences in their function and organization.
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Affiliation(s)
- David Alvarez-Ponce
- Department of Biology, National University of Ireland Maynooth, Maynooth, County Kildare, Ireland.
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Abstract
Simulation models of the evolution of genes in a branched metabolic pathway subject to stabilizing selection on flux are described and analyzed. The models are based either on metabolic control theory (MCT), with the assumption that enzymes are far from saturation, or on Michaelis-Menten kinetics, which allows for saturation and near saturation. Several predictions emerge from the models: (1) flux control evolves to be concentrated at pathway branch points, including the first enzyme in the pathway. (2) When flux is far from its optimum, adaptive substitutions occur disproportionately often in branching enzymes. (3) When flux is near its optimum, adaptive substitutions occur disproportionately often in nonbranching enzymes. (4) Slightly deleterious substitutions occur disproportionately often in nonbranching enzymes. (5) In terms of both flux control and patterns of substitution, pathway branches are similar to those predicted for linear pathways. These predictions provide null hypotheses for empirical examination of the evolution of genes in metabolic pathways.
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Affiliation(s)
- Mark D Rausher
- Department of Biology, Duke University, Durham, NC 27708, USA.
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de Pascale D, De Santi C, Fu J, Landfald B. The microbial diversity of Polar environments is a fertile ground for bioprospecting. Mar Genomics 2012. [PMID: 23199876 DOI: 10.1016/j.margen.2012.04.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The term bioprospecting has been adopted for systematic searches in nature for new bioactive compounds, genes, proteins, microorganisms and other products with potential for commercial use. Much effort has been focused on microorganisms able to thrive under harsh conditions, including the Polar environments. Both the lipid and protein cellular building blocks of Polar microorganisms are shaped by their adaptation to the permanently low temperatures. In addition, strongly differing environments, such as permafrost, glaciers and sea ice, have contributed to additional functional diversity. Emerging massive-parallel sequencing technologies have revealed the existence of a huge, hitherto unseen diversity of low-abundance phylotypes--the rare biosphere--even in the Polar environments. This realization has further strengthened the need to employ cultivation-independent approaches, including metagenomics and single-cell genomic sequencing, to get comprehensive access to the genetic diversity of microbial communities for bioprospecting purposes. In this review, we present an updated snapshot of recent findings on the molecular basis for adaptation to the cold and the phylogenetic diversities of different Polar environments. Novel approaches in bioprospecting are presented and we conclude by showing recent bioprospecting outcomes in terms of new molecules patented or applied by some biotech companies.
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Affiliation(s)
- Donatella de Pascale
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, I-80134 Naples, Italy.
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KVIST JOUNI, WHEAT CHRISTOPHERW, KALLIONIEMI EVELIINA, SAASTAMOINEN MARJO, HANSKI ILKKA, FRILANDER MIKKOJ. Temperature treatments during larval development reveal extensive heritable and plastic variation in gene expression and life history traits. Mol Ecol 2012; 22:602-19. [DOI: 10.1111/j.1365-294x.2012.05521.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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33
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Evolutionary Genomics of Colias Phosphoglucose Isomerase (PGI) Introns. J Mol Evol 2012; 74:96-111. [DOI: 10.1007/s00239-012-9492-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 02/15/2012] [Indexed: 10/28/2022]
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Experimental approaches to evaluate the contributions of candidate protein-coding mutations to phenotypic evolution. Methods Mol Biol 2012; 772:377-96. [PMID: 22065450 DOI: 10.1007/978-1-61779-228-1_22] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Identifying mechanisms of molecular adaptation can provide important insights into the process of phenotypic evolution, but it can be exceedingly difficult to quantify the phenotypic effects of specific mutational changes. To verify the adaptive significance of genetically based changes in protein function, it is necessary to document functional differences between the products of derived and wild-type alleles and to demonstrate that such differences impinge on higher-level physiological processes (and ultimately, fitness). In the case of metabolic enzymes, this requires documenting in vivo differences in reaction rate that give rise to differences in flux through the pathway in which the enzymes function. These measured differences in pathway flux should then give rise to differences in cellular or systemic physiology that affect fitness-related variation in whole-organism performance. Efforts to establish these causal connections between genotype, phenotype, and fitness require experiments that carefully control for environmental variation and background genetic variation. Here, we discuss experimental approaches to evaluate the contributions of amino-acid mutations to adaptive phenotypic change. We discuss conceptual and methodological issues associated with in vitro and in vivo studies of protein function, and the evolutionary insights that can be gleaned from such studies. We also discuss the importance of isolating the effects of individual mutations to distinguish between positively selected substitutions that directly contribute to improvements in protein function versus positively selected, compensatory substitutions that mitigate negative pleiotropic effects of antecedent changes.
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Schilder RJ, Zera AJ, Black C, Hoidal M, Wehrkamp C. The biochemical basis of life history adaptation: molecular and enzymological causes of NADP(+)-isocitrate dehydrogenase activity differences between morphs of Gryllus firmus that differ in lipid biosynthesis and life history. Mol Biol Evol 2011; 28:3381-93. [PMID: 21705380 DOI: 10.1093/molbev/msr171] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Although whole-organism aspects of life-history physiology are well studied and molecular information (e.g., transcript abundance) on life-history variation is accumulating rapidly, much less information is available on the biochemical (enzymological) basis of life-history adaptation. The present study investigated the biochemical and molecular causes of specific activity differences of the lipogenic enzyme, NADP(+)-isocitrate dehydrogenase, between genetic lines of the wing-polymorphic cricket, Gryllus firmus, which differ in lipid biosynthesis and life history. With one exception, variation among 21 Nadp(+)-Idh genomic sequences, which spanned the entire coding sequence of the gene, was restricted to a few synonymous substitutions within and among replicate flight-capable or flightless lines. No NADP(+)-IDH electromorph variation was observed among individuals within or among lines as determined by polyacrylamide gel electrophoresis. Nor did any NADP(+)-IDH kinetic or stability parameter, such as K(M) for substrate or cofactor, k(cat), or thermal denaturation, differ between flight-capable and flightless lines. By contrast, line differences in NADP(+)-IDH-specific activity strongly covaried with transcript abundance and enzyme protein concentration. These results demonstrate that NADP(+)-IDH-specific activity differences between artificially selected lines of G. firmus are due primarily, if not exclusively, to genetic variation in regulators of NADP(+)-IDH gene expression, with no observed contribution from altered catalytic efficiency of the enzyme due to changes in amino acid sequence or posttranslational modification. Kinetic analyses indicate that in vitro differences in enzyme-specific activity between flight-capable and flightless lines likely occur in vivo. This study constitutes the most comprehensive analysis to date of the biochemical and molecular causes of naturally occurring genetic variation in enzyme activity that covaries strongly with life history.
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Eanes WF. Molecular population genetics and selection in the glycolytic pathway. ACTA ACUST UNITED AC 2011; 214:165-71. [PMID: 21177937 DOI: 10.1242/jeb.046458] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
In this review, I discuss the evidence for differential natural selection acting across enzymes in the glycolytic pathway in Drosophila. Across the genome, genes evolve at very different rates and possess markedly varying levels of molecular polymorphism, codon bias and expression variation. Discovering the underlying causes of this variation has been a challenge in evolutionary biology. It has been proposed that both the intrinsic properties of enzymes and their pathway position have direct effects on their molecular evolution, and with the genomic era the study of adaptation has been taken to the level of pathways and networks of genes and their products. Of special interest have been the energy-producing pathways. Using both population genetic and experimental approaches, our laboratory has been engaged in a study of molecular variation across the glycolytic pathway in Drosophila melanogaster and its close relatives. We have observed a pervasive pattern in which genes at the top of the pathway, especially around the intersection at glucose 6-phosphate, show evidence for both contemporary selection, in the form of latitudinal allele clines, and inter-specific selection, in the form of elevated levels of amino acid substitutions between species. To further explore this question, future work will require corroboration in other species, expansion into tangential pathways, and experimental work to better characterize metabolic control through the pathway and to examine the pleiotropic effects of these genes on other traits and fitness components.
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Affiliation(s)
- Walter F Eanes
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11790, USA.
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Storz JF, Wheat CW. Integrating evolutionary and functional approaches to infer adaptation at specific loci. Evolution 2011; 64:2489-509. [PMID: 20500215 DOI: 10.1111/j.1558-5646.2010.01044.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Inferences about adaptation at specific loci are often exclusively based on the static analysis of DNA sequence variation. Ideally,population-genetic evidence for positive selection serves as a stepping-off point for experimental studies to elucidate the functional significance of the putatively adaptive variation. We argue that inferences about adaptation at specific loci are best achieved by integrating the indirect, retrospective insights provided by population-genetic analyses with the more direct, mechanistic insights provided by functional experiments. Integrative studies of adaptive genetic variation may sometimes be motivated by experimental insights into molecular function, which then provide the impetus to perform population genetic tests to evaluate whether the functional variation is of adaptive significance. In other cases, studies may be initiated by genome scans of DNA variation to identify candidate loci for recent adaptation. Results of such analyses can then motivate experimental efforts to test whether the identified candidate loci do in fact contribute to functional variation in some fitness-related phenotype. Functional studies can provide corroborative evidence for positive selection at particular loci, and can potentially reveal specific molecular mechanisms of adaptation.
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Affiliation(s)
- Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA.
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38
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Zera AJ. Microevolution of intermediary metabolism: evolutionary genetics meets metabolic biochemistry. J Exp Biol 2011; 214:179-90. [DOI: 10.1242/jeb.046912] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Summary
During the past decade, microevolution of intermediary metabolism has become an important new research focus at the interface between metabolic biochemistry and evolutionary genetics. Increasing recognition of the importance of integrative studies in evolutionary analysis, the rising interest in ‘evolutionary systems biology’, and the development of various ‘omics’ technologies have all contributed significantly to this developing interface. The present review primarily focuses on five prominent areas of recent research on pathway microevolution: lipid metabolism and life-history evolution; the electron transport system, hybrid breakdown and speciation; glycolysis, alcohol metabolism and population adaptation in Drosophila; chemostat selection in microorganisms; and anthocyanin pigment biosynthesis and flower color evolution. Some of these studies have provided a new perspective on important evolutionary topics that have not been investigated extensively from a biochemical perspective (hybrid breakdown, parallel evolution). Other studies have provided new data that augment previous biochemical information, resulting in a deeper understanding of evolutionary mechanisms (allozymes and biochemical adaptation to climate, life-history evolution, flower pigments and the genetics of adaptation). Finally, other studies have provided new insights into how the function or position of an enzyme in a pathway influences its evolutionary dynamics, in addition to providing powerful experimental models for investigations of network evolution. Microevolutionary studies of metabolic pathways will undoubtedly become increasingly important in the future because of the central importance of intermediary metabolism in organismal fitness, the wealth of biochemical data being provided by various omics technologies, and the increasing influence of integrative and systems perspectives in biology.
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Affiliation(s)
- Anthony J. Zera
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
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Alvarez-Ponce D, Aguadé M, Rozas J. Comparative genomics of the vertebrate insulin/TOR signal transduction pathway: a network-level analysis of selective pressures. Genome Biol Evol 2010; 3:87-101. [PMID: 21149867 PMCID: PMC3030423 DOI: 10.1093/gbe/evq084] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Complexity of biological function relies on large networks of interacting molecules. However, the evolutionary properties of these networks are not fully understood. It has been shown that selective pressures depend on the position of genes in the network. We have previously shown that in the Drosophila insulin/target of rapamycin (TOR) signal transduction pathway there is a correlation between the pathway position and the strength of purifying selection, with the downstream genes being most constrained. In this study, we investigated the evolutionary dynamics of this well-characterized pathway in vertebrates. More specifically, we determined the impact of natural selection on the evolution of 72 genes of this pathway. We found that in vertebrates there is a similar gradient of selective constraint in the insulin/TOR pathway to that found in Drosophila. This feature is neither the result of a polarity in the impact of positive selection nor of a series of factors affecting selective constraint levels (gene expression level and breadth, codon bias, protein length, and connectivity). We also found that pathway genes encoding physically interacting proteins tend to evolve under similar selective constraints. The results indicate that the architecture of the vertebrate insulin/TOR pathway constrains the molecular evolution of its components. Therefore, the polarity detected in Drosophila is neither specific nor incidental of this genus. Hence, although the underlying biological mechanisms remain unclear, these may be similar in both vertebrates and Drosophila.
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Affiliation(s)
- David Alvarez-Ponce
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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40
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Niitepõld K. Genotype by temperature interactions in the metabolic rate of the Glanville fritillary butterfly. ACTA ACUST UNITED AC 2010; 213:1042-8. [PMID: 20228340 DOI: 10.1242/jeb.034132] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Metabolic rate is a highly plastic trait. Here I examine factors that influence the metabolic rate of the Glanville fritillary butterfly (Melitaea cinxia) in pupae and resting and flying adults. Body mass and temperature had consistent positive effects on metabolic rate in pupae and resting adults but not in flying adults. There was also a consistent nonlinear effect of the time of the day, which was strongest in pupae and weakest in flying adults. Flight metabolic rate was strongly affected by an interaction between the phosphoglucose isomerase (Pgi) genotype and temperature. Over a broad range of measurement temperatures, heterozygous individuals at a single nucleotide polymorphism (SNP) in Pgi had higher peak metabolic rate in flight, but at high temperatures homozygous individuals performed better. The two genotypes did not differ in resting metabolic rate, suggesting that the heterozygotes do not pay an additional energetic cost for their higher flight capacity. Mass-independent resting and flight metabolic rates were at best weakly correlated at the individual level, and therefore, unlike in many vertebrates, resting metabolic rate does not serve as a useful surrogate of the metabolic capacity of this butterfly.
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Affiliation(s)
- Kristjan Niitepõld
- Department of Biological and Environmental Sciences, University of Helsinki, FI-00014, Helsinki, Finland.
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41
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Somero GN. The physiology of climate change: how potentials for acclimatization and genetic adaptation will determine 'winners' and 'losers'. ACTA ACUST UNITED AC 2010; 213:912-20. [PMID: 20190116 DOI: 10.1242/jeb.037473] [Citation(s) in RCA: 934] [Impact Index Per Article: 66.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Physiological studies can help predict effects of climate change through determining which species currently live closest to their upper thermal tolerance limits, which physiological systems set these limits, and how species differ in acclimatization capacities for modifying their thermal tolerances. Reductionist studies at the molecular level can contribute to this analysis by revealing how much change in sequence is needed to adapt proteins to warmer temperatures--thus providing insights into potential rates of adaptive evolution--and determining how the contents of genomes--protein-coding genes and gene regulatory mechanisms--influence capacities for adapting to acute and long-term increases in temperature. Studies of congeneric invertebrates from thermally stressful rocky intertidal habitats have shown that warm-adapted congeners are most susceptible to local extinctions because their acute upper thermal limits (LT(50) values) lie near current thermal maxima and their abilities to increase thermal tolerance through acclimation are limited. Collapse of cardiac function may underlie acute and longer-term thermal limits. Local extinctions from heat death may be offset by in-migration of genetically warm-adapted conspecifics from mid-latitude 'hot spots', where midday low tides in summer select for heat tolerance. A single amino acid replacement is sufficient to adapt a protein to a new thermal range. More challenging to adaptive evolution are lesions in genomes of stenotherms like Antarctic marine ectotherms, which have lost protein-coding genes and gene regulatory mechanisms needed for coping with rising temperature. These extreme stenotherms, along with warm-adapted eurytherms living near their thermal limits, may be the major 'losers' from climate change.
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Affiliation(s)
- G N Somero
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA 93950, USA.
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42
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Phosphoglucose isomerase (Pgi) performance and fitness effects among Arthropods and its potential role as an adaptive marker in conservation genetics. CONSERV GENET 2010. [DOI: 10.1007/s10592-009-0042-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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43
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The evolution of control and distribution of adaptive mutations in a metabolic pathway. Genetics 2009; 184:483-502. [PMID: 19966064 DOI: 10.1534/genetics.109.110411] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In an attempt to understand whether it should be expected that some genes tend to be used disproportionately often by natural selection, we investigated two related phenomena: the evolution of flux control among enzymes in a metabolic pathway and properties of adaptive substitutions in pathway enzymes. These two phenomena are related by the principle that adaptive substitutions should occur more frequently in enzymes with greater flux control. Predicting which enzymes will be preferentially involved in adaptive evolution thus requires an evolutionary theory of flux control. We investigated the evolution of enzyme control in metabolic pathways with two models of enzyme kinetics: metabolic control theory (MCT) and Michaelis-Menten saturation kinetics (SK). Our models generate two main predictions for pathways in which reactions are moderately to highly irreversible: (1) flux control will evolve to be highly unequal among enzymes in a pathway and (2) upstream enzymes evolve a greater control coefficient then those downstream. This results in upstream enzymes fixing the majority of beneficial mutations during adaptive evolution. Once the population has reached high fitness, the trend is reversed, with the majority of neutral/slightly deleterious mutations occurring in downstream enzymes. These patterns are the result of three factors (the first of these is unique to the MCT simulations while the other two seem to be general properties of the metabolic pathways): (1) the majority of randomly selected, starting combinations of enzyme kinetic rates generate pathways that possess greater control for the upstream enzymes compared to downstream enzymes; (2) selection against large pools of intermediate substrates tends to prevent majority control by downstream enzymes; and (3) equivalent mutations in enzyme kinetic rates have the greatest effect on flux for enzymes with high levels of flux control, and these enzymes will accumulate adaptive substitutions, strengthening their control. Prediction 1 is well supported by available data on control coefficients. Data for evaluating prediction 2 are sparse but not inconsistent with this prediction.
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Klemme I, Hanski I. Heritability of and strong single gene (Pgi) effects on life-history traits in the Glanville fritillary butterfly. J Evol Biol 2009; 22:1944-53. [PMID: 19702890 DOI: 10.1111/j.1420-9101.2009.01807.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We estimated broad-sense heritabilities (H(2)) of 13 female and seven male life-history traits of the Glanville fritillary butterfly (Melitaea cinxia) under semi-natural conditions in a large outdoor population cage. The analysis was based on full-sib families collected as young larvae in the field and reared under common garden conditions. We found significant genetic variance in female lifespan, fecundity, number of matings and host-plant preference as well as in male body mass and mobility. Apart from host-plant preference, female traits that were more strongly correlated with lifetime reproductive success (LRS; measured as total number of eggs laid) had higher H(2). LRS itself exhibited significant heritability. Host-plant preference had very high H(2), consistent with a previously reported genetically determined geographical cline in host-plant preference in the study area. Lifespan and egg hatching rate were significantly associated with a SNP in the coding region of the Pgi gene, for which there is previous evidence for balancing selection. Selection on Pgi, which furthermore shows spatial and temporal variation, may maintain genetic variance in fitness-related life-history traits. In contrast, we found no strong evidence for life-history trade-offs.
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Affiliation(s)
- I Klemme
- Metapopulation Research Group, Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
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45
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Dalziel AC, Rogers SM, Schulte PM. Linking genotypes to phenotypes and fitness: how mechanistic biology can inform molecular ecology. Mol Ecol 2009; 18:4997-5017. [PMID: 19912534 DOI: 10.1111/j.1365-294x.2009.04427.x] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The accessibility of new genomic resources, high-throughput molecular technologies and analytical approaches such as genome scans have made finding genes contributing to fitness variation in natural populations an increasingly feasible task. Once candidate genes are identified, we argue that it is necessary to take a mechanistic approach and work up through the levels of biological organization to fully understand the impacts of genetic variation at these candidate genes. We demonstrate how this approach provides testable hypotheses about the causal links among levels of biological organization, and assists in designing relevant experiments to test the effects of genetic variation on phenotype, whole-organism performance capabilities and fitness. We review some of the research programs that have incorporated mechanistic approaches when examining naturally occurring genetic and phenotypic variation and use these examples to highlight the value of developing a comprehensive understanding of the relationship between genotype and fitness. We give suggestions to guide future research aimed at uncovering and understanding the genetic basis of adaptation and argue that further integration of mechanistic approaches will help molecular ecologists better understand the evolution of natural populations.
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Affiliation(s)
- Anne C Dalziel
- Department of Zoology, University of British Columbia, Vancouver, Canada.
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46
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Jeyasingh PD, Weider LJ, Sterner RW. Genetically-based trade-offs in response to stoichiometric food quality influence competition in a keystone aquatic herbivore. Ecol Lett 2009; 12:1229-37. [PMID: 19719840 DOI: 10.1111/j.1461-0248.2009.01368.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Wheat CW, Haag CR, Marden JH, Hanski I, Frilander MJ. Nucleotide Polymorphism at a Gene (Pgi) under Balancing Selection in a Butterfly Metapopulation. Mol Biol Evol 2009; 27:267-81. [PMID: 19793833 DOI: 10.1093/molbev/msp227] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Christopher W Wheat
- Department of Biological and Environmental Sciences, University of Helsinki, Finland.
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Transcriptional regulation of metabolism associated with the increased desiccation resistance of the cactophilic Drosophila mojavensis. Genetics 2009; 182:1279-88. [PMID: 19487561 DOI: 10.1534/genetics.109.104927] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In Drosophila, adaptation to xeric environments presents many challenges, greatest among them the maintenance of water balance. Drosophila mojavensis, a cactophilic species from the deserts of North America, is one of the most desiccation resistant in the genus, surviving low humidity primarily by reducing its metabolic rate. Genetic control of reduced metabolic rate, however, has yet to be elucidated. We utilized the recently sequenced genome of D. mojavensis to create an oligonucleotide microarray to pursue the identities of the genes involved in metabolic regulation during desiccation. We observed large differences in gene expression between male and female D. mojavensis as well as both quantitative and qualitative sex differences in their ability to survive xeric conditions. As expected, genes associated with metabolic regulation and carbohydrate metabolism were differentially regulated between stress treatments. Most importantly, we identified four points in central metabolism (Glyceraldehyde 3-phosphate dehydrogenase, transaldolase, alcohol dehydrogenase, and phosphoenolpyruvate carboxykinase) that indicate the potential mechanisms controlling metabolic rate reduction associated with desiccation resistance. Furthermore, a large number of genes associated with vision pathways also were differentially expressed between stress treatments, especially in females, that may underlie the initial detection of stressful environments and trigger subsequent metabolic changes.
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Boutet I, Jollivet D, Shillito B, Moraga D, Tanguy A. Molecular identification of differentially regulated genes in the hydrothermal-vent species Bathymodiolus thermophilus and Paralvinella pandorae in response to temperature. BMC Genomics 2009; 10:222. [PMID: 19439073 PMCID: PMC2689276 DOI: 10.1186/1471-2164-10-222] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Accepted: 05/13/2009] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Hydrothermal vents and cold seeps represent oases of life in the deep-sea environment, but are also characterized by challenging physical and chemical conditions. The effect of temperature fluctuations on vent organisms in their habitat has not been well explored, in particular at a molecular level, most gene expression studies being conducted on coastal marine species. In order to better understand the response of hydrothermal organisms to different temperature regimes, differentially expressed genes (obtained by a subtractive suppression hybridization approach) were identified in the mussel Bathymodiolus thermophilus and the annelid Paralvinella pandorae irlandei to characterize the physiological processes involved when animals are subjected to long term exposure (2 days) at two contrasting temperatures (10 degrees versus 20 degrees C), while maintained at in situ pressures. To avoid a potential effect of pressure, the experimental animals were initially thermally acclimated for 24 hours in a pressurized vessel. RESULTS For each species, we produced two subtractive cDNA libraries (forward and reverse) from sets of deep-sea mussels and annelids exposed together to a thermal challenge under pressure. RNA extracted from the gills, adductor muscle, mantle and foot tissue were used for B. thermophilus. For the annelid model, whole animals (small individuals) were used. For each of the four libraries, we sequenced 200 clones, resulting in 78 and 83 unique sequences in mussels and annelids (about 20% of the sequencing effort), respectively, with only half of them corresponding to known genes. Real-time PCR was used to validate differentially expressed genes identified in the corresponding libraries. Strong expression variations have been observed for some specific genes such as the intracellular hemoglobin, the nidogen protein, and Rab7 in P. pandorae, and the SPARC protein, cyclophilin, foot protein and adhesive plaque protein in B. thermophilus. CONCLUSION Our results indicate that mussels and worms are not responding in the same way to temperature variations. While the results obtained for the mussel B. thermophilus seem to indicate a metabolic depression (strong decrease in the level of mRNA expression of numerous genes) when temperature increased, the annelid P. pandorae mainly displayed a strong regulation of the mRNA encoding subunits and linkers of respiratory pigments and some proteins involved in membrane structure. In both cases, these regulations seem to be partly due to a possible cellular oxidative stress induced by the simulated thermal environment (10 degrees C to 20 degrees C). This work will serve as a starting point for studying the transcriptomic response of hydrothermal mussels and annelids in future experiments in response to thermal stress at various conditions of duration and temperature challenge.
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Affiliation(s)
- Isabelle Boutet
- CNRS, UMR 7144, Adaptation et Diversité en Milieu Marin, Station Biologique, de Roscoff, 29682 Roscoff, France
- UPMC Univ Paris 06, UMR 7144, Equipe Génétique et Adaptation en Milieu Extrême, Station Biologique de Roscoff, 29682 Roscoff, France
| | - Didier Jollivet
- CNRS, UMR 7144, Adaptation et Diversité en Milieu Marin, Station Biologique, de Roscoff, 29682 Roscoff, France
- UPMC Univ Paris 06, UMR 7144, Equipe Génétique et Adaptation en Milieu Extrême, Station Biologique de Roscoff, 29682 Roscoff, France
| | - Bruce Shillito
- UPMC Université Paris 6, UMR 7138, Systématique, Adaptation et Evolution, 75005 Paris, France
| | - Dario Moraga
- UMR CNRS 6539, Laboratoire des Sciences de l'Environnement Marin, Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, Place Nicolas Copernic, 29280 Plouzané, France
| | - Arnaud Tanguy
- CNRS, UMR 7144, Adaptation et Diversité en Milieu Marin, Station Biologique, de Roscoff, 29682 Roscoff, France
- UPMC Univ Paris 06, UMR 7144, Equipe Génétique et Adaptation en Milieu Extrême, Station Biologique de Roscoff, 29682 Roscoff, France
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50
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Emergence of Complex Haplotypes from Microevolutionary Variation in Sequence and Structure of Colias Phosphoglucose Isomerase. J Mol Evol 2009; 68:433-47. [DOI: 10.1007/s00239-009-9237-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2008] [Revised: 03/03/2009] [Accepted: 04/08/2009] [Indexed: 10/20/2022]
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