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Vďačný P. Evolutionary Associations of Endosymbiotic Ciliates Shed Light on the Timing of the Marsupial-Placental Split. Mol Biol Evol 2018; 35:1757-1769. [PMID: 29659942 PMCID: PMC5995207 DOI: 10.1093/molbev/msy071] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Trichostome ciliates are among the most conspicuous protists in the gastrointestinal tract of a large variety of vertebrates. However, little is still known about phylogeny of the trichostome/vertebrate symbiotic systems, evolutionary correlations between trichostome extrinsic traits, and character-dependent diversification of trichostomes. These issues were investigated here, using the relaxed molecular clock technique along with stochastic mapping of character evolution, and binary-state speciation and extinction models. Clock analyses revealed that trichostomes colonized the vertebrate gastrointestinal tract ∼135 Ma, that is, near the paleontological minimum for the split of therian mammals into marsupials and placentals. According to stochastic mapping, the last common ancestor of trichostomes most likely invaded the hindgut of a mammal. Although multiple shifts to fish/amphibian or avian hosts and to the foregut compartments took place during the trichostome phylogeny, only transition to the foregut was recognized as a key innovation responsible for the explosive radiation of ophryoscolecid trichostomes after the Cretaceous/Tertiary boundary, when ungulates began their diversification. Since crown radiations of main trichostome lineages follow those of their mammalian hosts and are in agreement with their historic dispersal routes, the present time-calibrated phylogeny might help to elucidate controversies in the geological and molecular timing of the split between marsupials and placental mammals.
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Affiliation(s)
- Peter Vďačný
- Department of Zoology, Comenius University in Bratislava, Bratislava, Slovakia
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53
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Population genetic signatures of a climate change driven marine range extension. Sci Rep 2018; 8:9558. [PMID: 29934542 PMCID: PMC6015011 DOI: 10.1038/s41598-018-27351-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 05/20/2018] [Indexed: 11/08/2022] Open
Abstract
Shifts in species distribution, or 'range shifts', are one of the most commonly documented responses to ocean warming, with important consequences for the function and structure of ecosystems, and for socio-economic activities. Understanding the genetic signatures of range shifts can help build our knowledge of the capacity of species to establish and persist in colonised areas. Here, seven microsatellite loci were used to examine the population connectivity, genetic structure and diversity of Octopus tetricus, which has extended its distribution several hundred kilometres polewards associated with the southwards extension of the warm East Australian Current along south-eastern Australia. The historical distribution and the range extension zones had significant genetic differences but levels of genetic diversity were comparable. The population in the range extension zone was sub-structured, contained relatively high levels of self-recruitment and was sourced by migrants from along the entire geographic distribution. Genetic bottlenecks and changes in population size were detected throughout the range extension axis. Persistent gene flow from throughout the historical zone and moderate genetic diversity may buffer the genetic bottlenecks and favour the range extension of O. tetricus. These characteristics may aid adaptation, establishment, and long-term persistence of the population in the range extension zone.
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54
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Berger D, Stångberg J, Grieshop K, Martinossi-Allibert I, Arnqvist G. Temperature effects on life-history trade-offs, germline maintenance and mutation rate under simulated climate warming. Proc Biol Sci 2018; 284:rspb.2017.1721. [PMID: 29118134 DOI: 10.1098/rspb.2017.1721] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/06/2017] [Indexed: 01/28/2023] Open
Abstract
Mutation has a fundamental influence over evolutionary processes, but how evolutionary processes shape mutation rate remains less clear. In asexual unicellular organism, increased mutation rates have been observed in stressful environments and the reigning paradigm ascribes this increase to selection for evolvability. However, this explanation does not apply in sexually reproducing species, where little is known about how the environment affects mutation rate. Here we challenged experimental lines of seed beetle, evolved at ancestral temperature or under simulated climate warming, to repair induced mutations at ancestral and stressful temperature. Results show that temperature stress causes individuals to pass on a greater mutation load to their grand-offspring. This suggests that stress-induced mutation rates, in unicellular and multicellular organisms alike, can result from compromised germline DNA repair in low condition individuals. Moreover, lines adapted to simulated climate warming had evolved increased longevity at the cost of reproduction, and this allocation decision improved germline repair. These results suggest that mutation rates can be modulated by resource allocation trade-offs encompassing life-history traits and the germline and have important implications for rates of adaptation and extinction as well as our understanding of genetic diversity in multicellular organisms.
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Affiliation(s)
- David Berger
- Department of Ecology and Genetics, Animal Ecology, Uppsala University, Uppsala, Sweden
| | - Josefine Stångberg
- Department of Ecology and Genetics, Animal Ecology, Uppsala University, Uppsala, Sweden
| | - Karl Grieshop
- Department of Ecology and Genetics, Animal Ecology, Uppsala University, Uppsala, Sweden
| | | | - Göran Arnqvist
- Department of Ecology and Genetics, Animal Ecology, Uppsala University, Uppsala, Sweden
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55
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Fan H, Guo W. A genome-wide investigation of microsatellite mismatches and the association with body mass among bird species. PeerJ 2018; 6:e4495. [PMID: 29576965 PMCID: PMC5857172 DOI: 10.7717/peerj.4495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 02/21/2018] [Indexed: 01/26/2023] Open
Abstract
Mutation rate is usually found to covary with many life history traits of animals such as body mass, which has been readily explained by the higher number of mutation opportunities per unit time. Although the precise reason for the pattern is not yet clear, to determine the universality of this pattern, we tested whether life history traits impact another form of genetic mutation, the motif mismatches in microsatellites. Employing published genome sequences from 65 avian species, we explored the motif mismatches patterns of microsatellites in birds on a genomic level and assessed the relationship between motif mismatches and body mass in a phylogenetic context. We found that small-bodied species have a higher average mismatches and we suggested that higher heterozygosity in imperfect microsatellites lead to the increase of motif mismatches. Our results obtained from this study imply that a negative body mass trend in mutation rate may be a general pattern of avian molecular evolution.
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Affiliation(s)
- Haiying Fan
- Department of Ecology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Weibin Guo
- Department of Ecology, College of Life Sciences, Wuhan University, Wuhan, China
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56
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Ogilvie HA, Bouckaert RR, Drummond AJ. StarBEAST2 Brings Faster Species Tree Inference and Accurate Estimates of Substitution Rates. Mol Biol Evol 2018; 34:2101-2114. [PMID: 28431121 PMCID: PMC5850801 DOI: 10.1093/molbev/msx126] [Citation(s) in RCA: 248] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Fully Bayesian multispecies coalescent (MSC) methods like *BEAST estimate species trees from multiple sequence alignments. Today thousands of genes can be sequenced for a given study, but using that many genes with *BEAST is intractably slow. An alternative is to use heuristic methods which compromise accuracy or completeness in return for speed. A common heuristic is concatenation, which assumes that the evolutionary history of each gene tree is identical to the species tree. This is an inconsistent estimator of species tree topology, a worse estimator of divergence times, and induces spurious substitution rate variation when incomplete lineage sorting is present. Another class of heuristics directly motivated by the MSC avoids many of the pitfalls of concatenation but cannot be used to estimate divergence times. To enable fuller use of available data and more accurate inference of species tree topologies, divergence times, and substitution rates, we have developed a new version of *BEAST called StarBEAST2. To improve convergence rates we add analytical integration of population sizes, novel MCMC operators and other optimizations. Computational performance improved by 13.5× and 13.8× respectively when analyzing two empirical data sets, and an average of 33.1× across 30 simulated data sets. To enable accurate estimates of per-species substitution rates, we introduce species tree relaxed clocks, and show that StarBEAST2 is a more powerful and robust estimator of rate variation than concatenation. StarBEAST2 is available through the BEAUTi package manager in BEAST 2.4 and above.
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Affiliation(s)
- Huw A Ogilvie
- Division of Ecology and Evolution, Research School of Biology, Australian National University, Canberra, Australia.,Centre for Computational Evolution, University of Auckland, Auckland, New Zealand
| | - Remco R Bouckaert
- Centre for Computational Evolution, University of Auckland, Auckland, New Zealand.,Department of Computer Science, University of Auckland, Auckland, New Zealand
| | - Alexei J Drummond
- Centre for Computational Evolution, University of Auckland, Auckland, New Zealand.,Department of Computer Science, University of Auckland, Auckland, New Zealand
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57
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Bromham L, Duchêne S, Hua X, Ritchie AM, Duchêne DA, Ho SYW. Bayesian molecular dating: opening up the black box. Biol Rev Camb Philos Soc 2017; 93:1165-1191. [DOI: 10.1111/brv.12390] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 11/13/2017] [Accepted: 11/17/2017] [Indexed: 12/27/2022]
Affiliation(s)
- Lindell Bromham
- Macroevolution & Macroecology, Division of Ecology & Evolution, Research School of Biology; Australian National University; Canberra ACT 2601 Australia
| | - Sebastián Duchêne
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute; The University of Melbourne; Melbourne VIC 3010 Australia
- School of Life and Environmental Sciences; University of Sydney; Sydney NSW 2006 Australia
| | - Xia Hua
- Macroevolution & Macroecology, Division of Ecology & Evolution, Research School of Biology; Australian National University; Canberra ACT 2601 Australia
| | - Andrew M. Ritchie
- School of Life and Environmental Sciences; University of Sydney; Sydney NSW 2006 Australia
| | - David A. Duchêne
- Macroevolution & Macroecology, Division of Ecology & Evolution, Research School of Biology; Australian National University; Canberra ACT 2601 Australia
- School of Life and Environmental Sciences; University of Sydney; Sydney NSW 2006 Australia
| | - Simon Y. W. Ho
- School of Life and Environmental Sciences; University of Sydney; Sydney NSW 2006 Australia
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58
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Vekhnik VA. The Edible Dormouse (Glis glis, Gliridae, Rodentia) in the Periphery of Its Distribution Range: Body Size and Life History Parameters. BIOL BULL+ 2017. [DOI: 10.1134/s1062359017090163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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59
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Schroeder L, von Cramon-Taubadel N. The evolution of hominoid cranial diversity: A quantitative genetic approach. Evolution 2017; 71:2634-2649. [DOI: 10.1111/evo.13361] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 09/03/2017] [Indexed: 01/15/2023]
Affiliation(s)
- Lauren Schroeder
- Department of Anthropology; University of Toronto Mississauga; Mississauga ON L5L 1C6 Canada
- Buffalo Human Evolutionary Morphology Lab, Department of Anthropology; University at Buffalo; SUNY, Buffalo New York 14261
- Human Evolution Research Institute; University of Cape Town; Rondebosch 7701 South Africa
| | - Noreen von Cramon-Taubadel
- Buffalo Human Evolutionary Morphology Lab, Department of Anthropology; University at Buffalo; SUNY, Buffalo New York 14261
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60
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Lartillot N, Phillips MJ, Ronquist F. A mixed relaxed clock model. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0132. [PMID: 27325829 PMCID: PMC4920333 DOI: 10.1098/rstb.2015.0132] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/29/2016] [Indexed: 12/13/2022] Open
Abstract
Over recent years, several alternative relaxed clock models have been proposed in the context of Bayesian dating. These models fall in two distinct categories: uncorrelated and autocorrelated across branches. The choice between these two classes of relaxed clocks is still an open question. More fundamentally, the true process of rate variation may have both long-term trends and short-term fluctuations, suggesting that more sophisticated clock models unfolding over multiple time scales should ultimately be developed. Here, a mixed relaxed clock model is introduced, which can be mechanistically interpreted as a rate variation process undergoing short-term fluctuations on the top of Brownian long-term trends. Statistically, this mixed clock represents an alternative solution to the problem of choosing between autocorrelated and uncorrelated relaxed clocks, by proposing instead to combine their respective merits. Fitting this model on a dataset of 105 placental mammals, using both node-dating and tip-dating approaches, suggests that the two pure clocks, Brownian and white noise, are rejected in favour of a mixed model with approximately equal contributions for its uncorrelated and autocorrelated components. The tip-dating analysis is particularly sensitive to the choice of the relaxed clock model. In this context, the classical pure Brownian relaxed clock appears to be overly rigid, leading to biases in divergence time estimation. By contrast, the use of a mixed clock leads to more recent and more reasonable estimates for the crown ages of placental orders and superorders. Altogether, the mixed clock introduced here represents a first step towards empirically more adequate models of the patterns of rate variation across phylogenetic trees.This article is part of the themed issue 'Dating species divergences using rocks and clocks'.
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Affiliation(s)
- Nicolas Lartillot
- Laboratoire de Biométrie et Biologie Evolutive, UMR CNRS 5558, Université Claude Bernard Lyon 1, F-69622 Villeurbanne Cedex, France
| | - Matthew J Phillips
- School of Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, Australia
| | - Fredrik Ronquist
- Department of Bioinformatics and Genetics, Swedish Museum of Natural History, PO Box 50007, 104 05 Stockholm, Sweden
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61
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Coppard SE, Lessios HA. Phylogeography of the sand dollar genus Encope: implications regarding the Central American Isthmus and rates of molecular evolution. Sci Rep 2017; 7:11520. [PMID: 28912431 PMCID: PMC5599539 DOI: 10.1038/s41598-017-11875-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 08/31/2017] [Indexed: 11/23/2022] Open
Abstract
Vicariant events have been widely used to calibrate rates of molecular evolution, the completion of the Central American Isthmus more extensively than any other. Recent studies have claimed that rather than the generally accepted date of ~3 million years ago (Ma), the Isthmus was effectively complete by the middle Miocene, 13 Ma. We present a fossil calibrated phylogeny of the new world sand dollar genus Encope, based on one nuclear and four mitochondrial genes, calibrated with fossils at multiple nodes. Present day distributions of Encope are likely the result of multiple range contractions and extinction events. Most species are now endemic to a single region, but one widely distributed species in each ocean is composed of morphotypes previously described as separate species. The most recent separation between eastern Pacific and Caribbean extant clades occurred at 4.90 Ma, indicating that the Isthmus of Panama allowed genetic exchange until the Pliocene. The rate of evolution of mitochondrial genes in Encope has been ten times slower than in the closely related genera Mellita and Lanthonia. This large difference in rates suggests that splits between eastern Pacific and Caribbean biota, dated on the assumption of a "universal" mitochondrial DNA clock are not valid.
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Affiliation(s)
- Simon E Coppard
- Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Panama.
- Hamilton College, Department of Biology, 198 College Hill Road, Clinton, New York, 13323, USA.
| | - H A Lessios
- Smithsonian Tropical Research Institute, Box 0843-03092, Balboa, Panama
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62
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Abstract
Genome size in mammals and birds shows remarkably little interspecific variation compared with other taxa. However, genome sequencing has revealed that many mammal and bird lineages have experienced differential rates of transposable element (TE) accumulation, which would be predicted to cause substantial variation in genome size between species. Thus, we hypothesize that there has been covariation between the amount of DNA gained by transposition and lost by deletion during mammal and avian evolution, resulting in genome size equilibrium. To test this model, we develop computational methods to quantify the amount of DNA gained by TE expansion and lost by deletion over the last 100 My in the lineages of 10 species of eutherian mammals and 24 species of birds. The results reveal extensive variation in the amount of DNA gained via lineage-specific transposition, but that DNA loss counteracted this expansion to various extents across lineages. Our analysis of the rate and size spectrum of deletion events implies that DNA removal in both mammals and birds has proceeded mostly through large segmental deletions (>10 kb). These findings support a unified "accordion" model of genome size evolution in eukaryotes whereby DNA loss counteracting TE expansion is a major determinant of genome size. Furthermore, we propose that extensive DNA loss, and not necessarily a dearth of TE activity, has been the primary force maintaining the greater genomic compaction of flying birds and bats relative to their flightless relatives.
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63
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Hua X, Bromham L. Darwinism for the Genomic Age: Connecting Mutation to Diversification. Front Genet 2017; 8:12. [PMID: 28224003 PMCID: PMC5293951 DOI: 10.3389/fgene.2017.00012] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 01/19/2017] [Indexed: 12/30/2022] Open
Abstract
A growing body of evidence suggests that rates of diversification of biological lineages are correlated with differences in genome-wide mutation rate. Given that most research into differential patterns of diversification rate have focused on species traits or ecological parameters, a connection to the biochemical processes of genome change is an unexpected observation. While the empirical evidence for a significant association between mutation rate and diversification rate is mounting, there has been less effort in explaining the factors that mediate this connection between genetic change and species richness. Here we draw together empirical studies and theoretical concepts that may help to build links in the explanatory chain that connects mutation to diversification. First we consider the way that mutation rates vary between species. We then explore how differences in mutation rates have flow-through effects to the rate at which populations acquire substitutions, which in turn influences the speed at which populations become reproductively isolated from each other due to the acquisition of genomic incompatibilities. Since diversification rate is commonly measured from phylogenetic analyses, we propose a conceptual approach for relating events of reproductive isolation to bifurcations on molecular phylogenies. As we examine each of these relationships, we consider theoretical models that might shine a light on the observed association between rate of molecular evolution and diversification rate, and critically evaluate the empirical evidence for these links, focusing on phylogenetic comparative studies. Finally, we ask whether we are getting closer to a real understanding of the way that the processes of molecular evolution connect to the observable patterns of diversification.
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Affiliation(s)
- Xia Hua
- Centre for Macroevolution and Macroecology, Research School of Biology, Australian National University, Canberra ACT, Australia
| | - Lindell Bromham
- Centre for Macroevolution and Macroecology, Research School of Biology, Australian National University, Canberra ACT, Australia
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64
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Martinez PA, Jacobina UP, Fernandes RV, Brito C, Penone C, Amado TF, Fonseca CR, Bidau CJ. A comparative study on karyotypic diversification rate in mammals. Heredity (Edinb) 2016; 118:366-373. [PMID: 27804966 DOI: 10.1038/hdy.2016.110] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 09/19/2016] [Accepted: 09/27/2016] [Indexed: 01/23/2023] Open
Abstract
Chromosomal rearrangements have a relevant role in organismic evolution. However, little is known about the mechanisms that lead different phylogenetic clades to have different chromosomal rearrangement rates. Here, we investigate the causes behind the wide karyotypic diversity exhibited by mammals. In particular, we analyzed the role of metabolic, reproductive, biogeographic and genomic characteristics on the rates of macro- and microstructural karyotypic diversification (rKD) using comparative phylogenetic methods. We found evidence that reproductive characteristics such as larger litter size per year and longevity, by allowing a higher number of meioses in absolute time, favor a higher probability of chromosomal change. Furthermore, families with large geographic distributions but containing species with restricted geographic ranges showed a greater probability of fixation of macrostructural chromosomal changes in different geographic areas. Finally, rKD does not evolve by Brownian motion because the mutation rate depends on the concerted evolution of repetitive sequences. The decisive factors of rKD evolution will be natural selection, genetic drift and meiotic drive that will eventually allow or not the fixation of the rearrangements. Our results indicate that mammalian karyotypic diversity is influenced by historical and adaptive mechanisms where reproductive and genomic factors modulate the rate of chromosomal change.
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Affiliation(s)
- P A Martinez
- PIBi Lab-Laboratorio de Pesquisas Integrativas em Biodiversidade, Pós-Graduação em Ecologia e Conservação, Universidade Federal de Sergipe, São Cristovão, Brazil
| | | | - R V Fernandes
- Departamento de Ecologia, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| | - C Brito
- Departamento de Ecologia, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| | - C Penone
- Institute of Plant Science, University of Bern, Bern, Switzerland
| | - T F Amado
- BioMa-Biodiversity and Macroecology Lab, Department of Biology and Geology, Physics and Inorganic Chemistry, Rey Juan Carlos University, Mostoles, Spain
| | - C R Fonseca
- Departamento de Ecologia, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| | - C J Bidau
- Paraná y Los Claveles, Garupá, Argentina
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65
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Mohlhenrich ER, Mueller RL. Genetic drift and mutational hazard in the evolution of salamander genomic gigantism. Evolution 2016; 70:2865-2878. [DOI: 10.1111/evo.13084] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Revised: 09/27/2016] [Accepted: 09/27/2016] [Indexed: 12/25/2022]
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66
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Germline replications and somatic mutation accumulation are independent of vegetative life span in Arabidopsis. Proc Natl Acad Sci U S A 2016; 113:12226-12231. [PMID: 27729523 DOI: 10.1073/pnas.1609686113] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
In plants, gametogenesis occurs late in development, and somatic mutations can therefore be transmitted to the next generation. Longer periods of growth are believed to result in an increase in the number of cell divisions before gametogenesis, with a concomitant increase in mutations arising due to replication errors. However, there is little experimental evidence addressing how many cell divisions occur before gametogenesis. Here, we measured loss of telomeric DNA and accumulation of replication errors in Arabidopsis with short and long life spans to determine the number of replications in lineages leading to gametes. Surprisingly, the number of cell divisions within the gamete lineage is nearly independent of both life span and vegetative growth. One consequence of the relatively stable number of replications per generation is that older plants may not pass along more somatically acquired mutations to their offspring. We confirmed this hypothesis by genomic sequencing of progeny from young and old plants. This independence can be achieved by hierarchical arrangement of cell divisions in plant meristems where vegetative growth is primarily accomplished by expansion of cells in rapidly dividing meristematic zones, which are only rarely refreshed by occasional divisions of more quiescent cells. We support this model by 5-ethynyl-2'-deoxyuridine retention experiments in shoot and root apical meristems. These results suggest that stem-cell organization has independently evolved in plants and animals to minimize mutations by limiting DNA replication.
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67
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R Marcelino V, Cremen MCM, Jackson CJ, Larkum AAW, Verbruggen H. Evolutionary Dynamics of Chloroplast Genomes in Low Light: A Case Study of the Endolithic Green Alga Ostreobium quekettii. Genome Biol Evol 2016; 8:2939-2951. [PMID: 27566760 PMCID: PMC5633697 DOI: 10.1093/gbe/evw206] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Some photosynthetic organisms live in extremely low light environments. Light limitation is associated with selective forces as well as reduced exposure to mutagens, and over evolutionary timescales it can leave a footprint on species’ genomes. Here, we present the chloroplast genomes of four green algae (Bryopsidales, Ulvophyceae), including the endolithic (limestone-boring) alga Ostreobium quekettii, which is a low light specialist. We use phylogenetic models and comparative genomic tools to investigate whether the chloroplast genome of Ostreobium corresponds to our expectations of how low light would affect genome evolution. Ostreobium has the smallest and most gene-dense chloroplast genome among Ulvophyceae reported to date, matching our expectation that light limitation would impose resource constraints reflected in the chloroplast genome architecture. Rates of molecular evolution are significantly slower along the phylogenetic branch leading to Ostreobium, in agreement with the expected effects of low light and energy levels on molecular evolution. We expected the ability of Ostreobium to perform photosynthesis in very low light to be associated with positive selection in genes related to the photosynthetic machinery, but instead, we observed that these genes may be under stronger purifying selection. Besides shedding light on the genome dynamics associated with a low light lifestyle, this study helps to resolve the role of environmental factors in shaping the diversity of genome architectures observed in nature.
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Affiliation(s)
| | | | | | - Anthony A W Larkum
- Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, NSW 2007, Australia
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68
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Gatesy J, Meredith RW, Janecka JE, Simmons MP, Murphy WJ, Springer MS. Resolution of a concatenation/coalescence kerfuffle: partitioned coalescence support and a robust family‐level tree for Mammalia. Cladistics 2016; 33:295-332. [DOI: 10.1111/cla.12170] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2016] [Indexed: 12/14/2022] Open
Affiliation(s)
- John Gatesy
- Department of Biology University of California Riverside CA 92521 USA
| | - Robert W. Meredith
- Department of Biology and Molecular Biology Montclair State University Montclair NJ 07043 USA
| | - Jan E. Janecka
- Department of Biological Sciences Duquesne University Pittsburgh PA 15282 USA
| | - Mark P. Simmons
- Department of Biology Colorado State University Fort Collins CO 80523 USA
| | - William J. Murphy
- Department of Veterinary Integrative Biosciences Texas A&M University College Station TX 77843 USA
| | - Mark S. Springer
- Department of Biology University of California Riverside CA 92521 USA
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69
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James JE, Lanfear R, Eyre-Walker A. Molecular Evolutionary Consequences of Island Colonization. Genome Biol Evol 2016; 8:1876-88. [PMID: 27358424 PMCID: PMC4943191 DOI: 10.1093/gbe/evw120] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Island endemics are expected to have low effective population sizes (Ne), first because some may experience population bottlenecks when they are founded, and second because they have restricted ranges. Therefore, we expect island species to have reduced genetic diversity, inefficient selection, and reduced adaptive potential compared with their mainland counterparts. We used both polymorphism and substitution data to address these predictions, improving on the approach of recent studies that only used substitution data. This allowed us to directly test the assumption that island species have small values of Ne We found that island species had significantly less genetic diversity than mainland species; however, this pattern could be attributed to a subset of island species that appeared to have undergone a recent population bottleneck. When these species were excluded from the analysis, island and mainland species had similar levels of genetic diversity, despite island species occupying considerably smaller areas than their mainland counterparts. We also found no overall difference between island and mainland species in terms of the effectiveness of selection or the mutation rate. Our evidence suggests that island colonization has no lasting impact on molecular evolution. This surprising result highlights gaps in our knowledge of the relationship between census and effective population size.
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Affiliation(s)
- Jennifer E James
- School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Robert Lanfear
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia Division of Evolution Ecology and Genetics, Research School of Biology, the Australian National University, Canberra, Australian Capital Territory, Australia
| | - Adam Eyre-Walker
- School of Life Sciences, University of Sussex, Brighton, United Kingdom
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Quetglas A, Rueda L, Alvarez-Berastegui D, Guijarro B, Massutí E. Contrasting Responses to Harvesting and Environmental Drivers of Fast and Slow Life History Species. PLoS One 2016; 11:e0148770. [PMID: 26859577 PMCID: PMC4747561 DOI: 10.1371/journal.pone.0148770] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 01/22/2016] [Indexed: 11/19/2022] Open
Abstract
According to their main life history traits, organisms can be arranged in a continuum from fast (species with small body size, short lifespan and high fecundity) to slow (species with opposite characteristics). Life history determines the responses of organisms to natural and anthropogenic factors, as slow species are expected to be more sensitive than fast species to perturbations. Owing to their contrasting traits, cephalopods and elasmobranchs are typical examples of fast and slow strategies, respectively. We investigated the responses of these two contrasting strategies to fishing exploitation and environmental conditions (temperature, productivity and depth) using generalized additive models. Our results confirmed the foreseen contrasting responses of cephalopods and elasmobranchs to natural (environment) and anthropogenic (harvesting) influences. Even though a priori foreseen, we did expect neither the clear-cut differential responses between groups nor the homogeneous sensitivity to the same factors within the two taxonomic groups. Apart from depth, which affected both groups equally, cephalopods and elasmobranchs were exclusively affected by environmental conditions and fishing exploitation, respectively. Owing to its short, annual cycle, cephalopods do not have overlapping generations and consequently lack the buffering effects conferred by different age classes observed in multi-aged species such as elasmobranchs. We suggest that cephalopods are sensitive to short-term perturbations, such as seasonal environmental changes, because they lack this buffering effect but they are in turn not influenced by continuous, long-term moderate disturbances such as fishing because of its high population growth and turnover. The contrary would apply to elasmobranchs, whose multi-aged population structure would buffer the seasonal environmental effects, but they would display strong responses to uninterrupted harvesting due to its low population resilience. Besides providing empirical evidence to the theoretically predicted contrasting responses of cephalopods and elasmobranchs to disturbances, our results are useful for the sustainable exploitation of these resources.
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Affiliation(s)
- Antoni Quetglas
- Instituto Español de Oceanografía, Centre Oceanogràfic de les Balears, Palma de Mallorca, Spain
- * E-mail:
| | - Lucía Rueda
- Instituto Español de Oceanografía, Centre Oceanogràfic de les Balears, Palma de Mallorca, Spain
| | | | - Beatriz Guijarro
- Instituto Español de Oceanografía, Centre Oceanogràfic de les Balears, Palma de Mallorca, Spain
| | - Enric Massutí
- Instituto Español de Oceanografía, Centre Oceanogràfic de les Balears, Palma de Mallorca, Spain
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71
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Hoareau TB. Late Glacial Demographic Expansion Motivates a Clock Overhaul for Population Genetics. Syst Biol 2015; 65:449-64. [PMID: 26683588 DOI: 10.1093/sysbio/syv120] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Accepted: 12/10/2015] [Indexed: 12/18/2022] Open
Abstract
The molecular clock hypothesis is fundamental in evolutionary biology as by assuming constancy of the molecular rate it provides a timeframe for evolution. However, increasing evidence shows time dependence of inferred molecular rates with inflated values obtained using recent calibrations. As recent demographic calibrations are virtually non-existent in most species, older phylogenetic calibration points (>1 Ma) are commonly used, which overestimate demographic parameters. To obtain more reliable rates of molecular evolution for population studies, I propose the calibration of demographic transition (CDT) method, which uses the timing of climatic changes over the late glacial warming period to calibrate expansions in various species. Simulation approaches and empirical data sets from a diversity of species (from mollusk to humans) confirm that, when compared with other genealogy-based calibration methods, the CDT provides a robust and broadly applicable clock for population genetics. The resulting CDT rates of molecular evolution also confirm rate heterogeneity over time and among taxa. Comparisons of expansion dates with ecological evidence confirm the inaccuracy of phylogenetically derived divergence rates when dating population-level events. The CDT method opens opportunities for addressing issues such as demographic responses to past climate change and the origin of rate heterogeneity related to taxa, genes, time, and genetic information content.
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Affiliation(s)
- Thierry B Hoareau
- Molecular Ecology and Evolution Programme, Department of Genetics, University of Pretoria, Private bag X20, Hatfield, Pretoria 0028, South Africa
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72
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Phillips MJ. Geomolecular Dating and the Origin of Placental Mammals. Syst Biol 2015; 65:546-57. [PMID: 26658702 DOI: 10.1093/sysbio/syv115] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/03/2015] [Indexed: 11/13/2022] Open
Abstract
In modern evolutionary divergence analysis the role of geological information extends beyond providing a timescale, to informing molecular rate variation across the tree. Here I consider the implications of this development. I use fossil calibrations to test the accuracy of models of molecular rate evolution for placental mammals, and reveal substantial misspecification associated with life history rate correlates. Adding further calibrations to reduce dating errors at specific nodes unfortunately tends to transfer underlying rate errors to adjacent branches. Thus, tight calibration across the tree is vital to buffer against rate model errors. I argue that this must include allowing maximum bounds to be tight when good fossil records permit, otherwise divergences deep in the tree will tend to be inflated by the interaction of rate errors and asymmetric confidence in minimum and maximum bounds. In the case of placental mammals I sought to reduce the potential for transferring calibration and rate model errors across the tree by focusing on well-supported calibrations with appropriately conservative maximum bounds. The resulting divergence estimates are younger than others published recently, and provide the long-anticipated molecular signature for the placental mammal radiation observed in the fossil record near the 66 Ma Cretaceous-Paleogene extinction event.
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Affiliation(s)
- Matthew J Phillips
- School of Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, QLD 4000, Australia
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73
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Rodríguez RA, Herrera AM, Santander J, Miranda JV, Fernández-Rodríguez MJ, Quirós Á, Riera R, Fernández-Palacios JM, Otto R, Escudero CG, Jiménez-Rodríguez A, Navarro-Cerrillo RM, Perdomo ME, Delgado JD. Uncertainty principle in niche assessment: A solution to the dilemma redundancy vs. competitive exclusion, and some analytical consequences. Ecol Modell 2015. [DOI: 10.1016/j.ecolmodel.2015.07.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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74
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Hope AG, Waltari E, Malaney JL, Payer DC, Cook JA, Talbot SL. Arctic biodiversity: increasing richness accompanies shrinking refugia for a cold-associated tundra fauna. Ecosphere 2015. [DOI: 10.1890/es15-00104.1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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75
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Weber CC, Nabholz B, Romiguier J, Ellegren H. Kr/Kc but not dN/dS correlates positively with body mass in birds, raising implications for inferring lineage-specific selection. Genome Biol 2015; 15:542. [PMID: 25607475 PMCID: PMC4264323 DOI: 10.1186/s13059-014-0542-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 11/13/2014] [Indexed: 02/02/2023] Open
Abstract
Background The ratio of the rates of non-synonymous and synonymous substitution (dN/dS) is commonly used to estimate selection in coding sequences. It is often suggested that, all else being equal, dN/dS should be lower in populations with large effective size (Ne) due to increased efficacy of purifying selection. As Ne is difficult to measure directly, life history traits such as body mass, which is typically negatively associated with population size, have commonly been used as proxies in empirical tests of this hypothesis. However, evidence of whether the expected positive correlation between body mass and dN/dS is consistently observed is conflicting. Results Employing whole genome sequence data from 48 avian species, we assess the relationship between rates of molecular evolution and life history in birds. We find a negative correlation between dN/dS and body mass, contrary to nearly neutral expectation. This raises the question whether the correlation might be a method artefact. We therefore in turn consider non-stationary base composition, divergence time and saturation as possible explanations, but find no clear patterns. However, in striking contrast to dN/dS, the ratio of radical to conservative amino acid substitutions (Kr/Kc) correlates positively with body mass. Conclusions Our results in principle accord with the notion that non-synonymous substitutions causing radical amino acid changes are more efficiently removed by selection in large populations, consistent with nearly neutral theory. These findings have implications for the use of dN/dS and suggest that caution is warranted when drawing conclusions about lineage-specific modes of protein evolution using this metric. Electronic supplementary material The online version of this article (doi:10.1186/s13059-014-0542-8) contains supplementary material, which is available to authorized users.
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76
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Abstract
Our understanding of molecular evolution is hampered by a lack of quantitative predictions about how life-history (LH) traits should correlate with substitution rates. Comparative studies have shown that neutral substitution rates vary substantially between species, and evidence shows that much of this diversity is associated with variation in LH traits. However, while these studies often agree, some unexplained and contradictory results have emerged. Explaining these results is difficult without a clear theoretical understanding of the problem. In this study, we derive predictions for the relationships between LH traits and substitution rates in iteroparous species by using demographic theory to relate commonly measured life-history traits to genetic generation time, and by implication to neutral substitution rates. This provides some surprisingly simple explanations for otherwise confusing patterns, such as the association between fecundity and substitution rates. The same framework can be applied to more complex life histories if full life-tables are available.
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Affiliation(s)
- Jussi Lehtonen
- Evolutionary Biology, Zoological Institute, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland Centre of Excellence in Biological Interactions and Division of Evolution Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - Robert Lanfear
- Centre of Excellence in Biological Interactions and Division of Evolution Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia National Evolutionary Synthesis Center, Durham, NC 27705-4667, USA Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
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77
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Abstract
ABSTRACT Cancers exhibit differences in metastatic behavior and drug sensitivity that correlate with certain tumor-specific variables such as differentiation grade, growth rate/extent and molecular regulatory aberrations. In practice, patient management is based on the past results of clinical trials adjusted for these biomarkers. Here, it is proposed that treatment strategies could be fine-tuned upfront simply by quantifying tumorigenic spatial (cell growth) and temporal (genetic stability) control losses, as predicted by genetic defects of cell-cycle-regulatory gatekeeper and genome-stabilizing caretaker tumor suppressor genes, respectively. These differential quantifications of tumor dysfunction may in turn be used to create a tumor-specific ‘periodic table’ that guides rational formulation of survival-enhancing anticancer treatment strategies.
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Affiliation(s)
- Richard J Epstein
- *Clinical Informatics & Research Centre, The Kinghorn Cancer Centre, 370 Victoria St, Darlinghurst 2010, Sydney, Australia
- Laboratory of Genome Evolution, Garvan Institute for Medical Research, 384 Victoria St, Darlinghurst 2010, Sydney, Australia
- Department of Oncology, & UNSW Clinical School, St Vincent's Hospital, 390 Victoria St, Darlinghurst 2010 Sydney, Australia
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78
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Emerson BC, Hickerson MJ. Lack of support for the time-dependent molecular evolution hypothesis. Mol Ecol 2015; 24:702-9. [DOI: 10.1111/mec.13070] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 12/17/2014] [Accepted: 12/30/2014] [Indexed: 01/24/2023]
Affiliation(s)
- Brent C. Emerson
- Island Ecology and Evolution Research Group; Instituto de Productos Naturales y Agrobiología (IPNA-CSIC); C/Astrofísico Francisco Sánchez 3 La Laguna Tenerife, Canary Islands 38206 Spain
| | - Michael J. Hickerson
- Biology Department; City College of New York; New York NY 10031 USA
- The Graduate Center; City University of New York; New York NY 10016 USA
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79
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Davies KTJ, Tsagkogeorga G, Rossiter SJ. Divergent evolutionary rates in vertebrate and mammalian specific conserved non-coding elements (CNEs) in echolocating mammals. BMC Evol Biol 2014; 14:261. [PMID: 25523630 PMCID: PMC4302572 DOI: 10.1186/s12862-014-0261-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 12/08/2014] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND The majority of DNA contained within vertebrate genomes is non-coding, with a certain proportion of this thought to play regulatory roles during development. Conserved Non-coding Elements (CNEs) are an abundant group of putative regulatory sequences that are highly conserved across divergent groups and thus assumed to be under strong selective constraint. Many CNEs may contain regulatory factor binding sites, and their frequent spatial association with key developmental genes - such as those regulating sensory system development - suggests crucial roles in regulating gene expression and cellular patterning. Yet surprisingly little is known about the molecular evolution of CNEs across diverse mammalian taxa or their role in specific phenotypic adaptations. We examined 3,110 vertebrate-specific and ~82,000 mammalian-specific CNEs across 19 and 9 mammalian orders respectively, and tested for changes in the rate of evolution of CNEs located in the proximity of genes underlying the development or functioning of auditory systems. As we focused on CNEs putatively associated with genes underlying the development/functioning of auditory systems, we incorporated echolocating taxa in our dataset because of their highly specialised and derived auditory systems. RESULTS Phylogenetic reconstructions of concatenated CNEs broadly recovered accepted mammal relationships despite high levels of sequence conservation. We found that CNE substitution rates were highest in rodents and lowest in primates, consistent with previous findings. Comparisons of CNE substitution rates from several genomic regions containing genes linked to auditory system development and hearing revealed differences between echolocating and non-echolocating taxa. Wider taxonomic sampling of four CNEs associated with the homeobox genes Hmx2 and Hmx3 - which are required for inner ear development - revealed family-wise variation across diverse bat species. Specifically within one family of echolocating bats that utilise frequency-modulated echolocation calls varying widely in frequency and intensity high levels of sequence divergence were found. CONCLUSIONS Levels of selective constraint acting on CNEs differed both across genomic locations and taxa, with observed variation in substitution rates of CNEs among bat species. More work is needed to determine whether this variation can be linked to echolocation, and wider taxonomic sampling is necessary to fully document levels of conservation in CNEs across diverse taxa.
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Affiliation(s)
- Kalina T J Davies
- School of Biological & Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
| | - Georgia Tsagkogeorga
- School of Biological & Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
| | - Stephen J Rossiter
- School of Biological & Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
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80
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Cowman PF. Historical factors that have shaped the evolution of tropical reef fishes: a review of phylogenies, biogeography, and remaining questions. Front Genet 2014; 5:394. [PMID: 25431581 PMCID: PMC4230204 DOI: 10.3389/fgene.2014.00394] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 10/27/2014] [Indexed: 12/21/2022] Open
Abstract
Biodiversity patterns across the marine tropics have intrigued evolutionary biologists and ecologists alike. Tropical coral reefs host 1/3 of all marine species of fish on 0.1% of the ocean's surface. Yet our understanding of how mechanistic processes have underpinned the generation of this diversity is limited. However, it has become clear that the biogeographic history of the marine tropics has played an important role in shaping the diversity of tropical reef fishes we see today. In the last decade, molecular phylogenies and age estimation techniques have provided a temporal framework in which the ancestral biogeographic origins of reef fish lineages have been inferred, but few have included fully sampled phylogenies or made inferences at a global scale. We are currently at a point where new sequencing technologies are accelerating the reconstruction and the resolution of the Fish Tree of Life. How will a complete phylogeny of fishes benefit the study of biodiversity in the tropics? Here, I review the literature concerning the evolutionary history of reef-associated fishes from a biogeographic perspective. I summarize the major biogeographic and climatic events over the last 65 million years that have regionalized the tropical marine belt and what effect they have had on the molecular record of fishes and global biodiversity patterns. By examining recent phylogenetic trees of major reef associated groups, I identify gaps to be filled in order to obtain a clearer picture of the origins of coral reef fish assemblages. Finally, I discuss questions that remain to be answered and new approaches to uncover the mechanistic processes that underpin the evolution of biodiversity on coral reefs.
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Affiliation(s)
- Peter F Cowman
- Department of Ecology and Evolutionary Biology, Yale University New Haven, CT, USA
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81
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Amos W, Filipe LN. Microsatellite frequencies vary with body mass and body temperature in mammals, suggesting correlated variation in mutation rate. PeerJ 2014; 2:e663. [PMID: 25392761 PMCID: PMC4226647 DOI: 10.7717/peerj.663] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Accepted: 10/21/2014] [Indexed: 11/20/2022] Open
Abstract
Substitution rate is often found to correlate with life history traits such as body mass, a predictor of population size and longevity, and body temperature. The underlying mechanism is unclear but most models invoke either natural selection or factors such as generation length that change the number of mutation opportunities per unit time. Here we use published genome sequences from 69 mammals to ask whether life history traits impact another form of genetic mutation, the high rates of predominantly neutral slippage in microsatellites. We find that the length-frequency distributions of three common dinucleotide motifs differ greatly between even closely related species. These frequency differences correlate with body mass and body temperature and can be used to predict the phenotype of an unknown species. Importantly, different length microsatellites show complicated patterns of excess and deficit that cannot be explained by a simple model where species with short generation lengths have experienced more mutations. Instead, the patterns probably require changes in mutation rate that impact alleles of different length to different extents. Body temperature plausibly influences mutation rate by modulating the propensity for slippage. Existing hypotheses struggle to account for a link between body mass and mutation rate. However, body mass correlates inversely with population size, which in turn predicts heterozygosity. We suggest that heterozygote instability, HI, the idea that heterozygous sites show increased mutability, could provide a plausible link between body mass and mutation rate.
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82
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Ho SYW, Duchêne S. Molecular-clock methods for estimating evolutionary rates and timescales. Mol Ecol 2014; 23:5947-65. [DOI: 10.1111/mec.12953] [Citation(s) in RCA: 225] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 09/29/2014] [Accepted: 09/30/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Simon Y. W. Ho
- School of Biological Sciences; University of Sydney; Sydney NSW 2006 Australia
| | - Sebastián Duchêne
- School of Biological Sciences; University of Sydney; Sydney NSW 2006 Australia
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83
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Ségurel L, Wyman MJ, Przeworski M. Determinants of Mutation Rate Variation in the Human Germline. Annu Rev Genomics Hum Genet 2014; 15:47-70. [DOI: 10.1146/annurev-genom-031714-125740] [Citation(s) in RCA: 232] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Laure Ségurel
- Laboratoire Éco-Anthropologie et Ethnobiologie, UMR 7206, Muséum National d'Histoire Naturelle–Centre National de la Recherche Scientifique–Université Paris 7 Diderot, Paris 75231, France;
| | - Minyoung J. Wyman
- Department of Biological Sciences, Columbia University, New York, NY 10027;
| | - Molly Przeworski
- Department of Human Genetics and Howard Hughes Medical Institute, University of Chicago, Chicago, Illinois 60637;
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84
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Dávalos LM, Russell AL. Sex-biased dispersal produces high error rates in mitochondrial distance-based and tree-based species delimitation. J Mammal 2014. [DOI: 10.1644/14-mamm-a-107] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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85
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Ho SYW. The changing face of the molecular evolutionary clock. Trends Ecol Evol 2014; 29:496-503. [PMID: 25086668 DOI: 10.1016/j.tree.2014.07.004] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 07/03/2014] [Accepted: 07/08/2014] [Indexed: 11/30/2022]
Abstract
The molecular clock has played an important role in biological research, both as a description of the evolutionary process and as a tool for inferring evolutionary timescales. Genomic data have provided valuable insights into the molecular clock, allowing the patterns and causes of evolutionary rate variation to be characterized in increasing detail. I explain how genome sequences offer exciting opportunities for estimating the timescale of the Tree of Life. I describe the different approaches that have been used to deal with the computational and statistical challenges encountered in molecular clock analyses of genomic data. Finally, I offer a perspective on the future of molecular clocks, highlighting some of the key limitations and the most promising research directions.
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Affiliation(s)
- Simon Y W Ho
- School of Biological Sciences, University of Sydney, Sydney, NSW, Australia.
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86
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Hope AG, Ho SYW, Malaney JL, Cook JA, Talbot SL. ACCOUNTING FOR RATE VARIATION AMONG LINEAGES IN COMPARATIVE DEMOGRAPHIC ANALYSES. Evolution 2014; 68:2689-700. [DOI: 10.1111/evo.12469] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Accepted: 05/22/2014] [Indexed: 01/16/2023]
Affiliation(s)
- Andrew G. Hope
- U.S. Geological Survey; Alaska Science Center; 4210 University Drive Anchorage Alaska 99508
| | - Simon Y. W. Ho
- School of Biological Sciences; Edgeworth David Building A11; The University of Sydney; Sydney New South Wales 2006 Australia
| | - Jason L. Malaney
- Department of Natural Resources and Environmental Science; University of Nevada-Reno; Reno Nevada 89557
| | - Joseph A. Cook
- Department of Biology; University of New Mexico; Museum of Southwestern Biology MSC03 2020; Albuquerque New Mexico 87131
| | - Sandra L. Talbot
- U.S. Geological Survey; Alaska Science Center; 4210 University Drive Anchorage Alaska 99508
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87
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Pozzi L, Hodgson JA, Burrell AS, Sterner KN, Raaum RL, Disotell TR. Primate phylogenetic relationships and divergence dates inferred from complete mitochondrial genomes. Mol Phylogenet Evol 2014; 75:165-83. [PMID: 24583291 PMCID: PMC4059600 DOI: 10.1016/j.ympev.2014.02.023] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Revised: 02/17/2014] [Accepted: 02/19/2014] [Indexed: 01/23/2023]
Abstract
The origins and the divergence times of the most basal lineages within primates have been difficult to resolve mainly due to the incomplete sampling of early fossil taxa. The main source of contention is related to the discordance between molecular and fossil estimates: while there are no crown primate fossils older than 56Ma, most molecule-based estimates extend the origins of crown primates into the Cretaceous. Here we present a comprehensive mitogenomic study of primates. We assembled 87 mammalian mitochondrial genomes, including 62 primate species representing all the families of the order. We newly sequenced eleven mitochondrial genomes, including eight Old World monkeys and three strepsirrhines. Phylogenetic analyses support a strong topology, confirming the monophyly for all the major primate clades. In contrast to previous mitogenomic studies, the positions of tarsiers and colugos relative to strepsirrhines and anthropoids are well resolved. In order to improve our understanding of how fossil calibrations affect age estimates within primates, we explore the effect of seventeen fossil calibrations across primates and other mammalian groups and we select a subset of calibrations to date our mitogenomic tree. The divergence date estimates of the Strepsirrhine/Haplorhine split support an origin of crown primates in the Late Cretaceous, at around 74Ma. This result supports a short-fuse model of primate origins, whereby relatively little time passed between the origin of the order and the diversification of its major clades. It also suggests that the early primate fossil record is likely poorly sampled.
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Affiliation(s)
- Luca Pozzi
- Department of Anthropology, Center for the Study of Human Origins, New York University, New York, NY, United States; New York Consortium in Evolutionary Primatology, United States; Behavioral Ecology and Sociobiology Unit, German Primate Center, Göttingen, Germany.
| | - Jason A Hodgson
- Department of Anthropology, Center for the Study of Human Origins, New York University, New York, NY, United States; New York Consortium in Evolutionary Primatology, United States; Department of Life Sciences, Imperial College London, London, United Kingdom.
| | - Andrew S Burrell
- Department of Anthropology, Center for the Study of Human Origins, New York University, New York, NY, United States.
| | - Kirstin N Sterner
- Department of Anthropology, University of Oregon, Eugene, OR, United States.
| | - Ryan L Raaum
- New York Consortium in Evolutionary Primatology, United States; Department of Anthropology, Lehman College & The Graduate Center, City University of New York, Bronx, NY, United States.
| | - Todd R Disotell
- Department of Anthropology, Center for the Study of Human Origins, New York University, New York, NY, United States; New York Consortium in Evolutionary Primatology, United States.
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88
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Scombroid Fishes Provide Novel Insights into the Trait/Rate Associations of Molecular Evolution. J Mol Evol 2014; 78:338-48. [DOI: 10.1007/s00239-014-9621-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 04/19/2014] [Indexed: 12/25/2022]
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89
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Snir S, Wolf YI, Koonin EV. Universal pacemaker of genome evolution in animals and fungi and variation of evolutionary rates in diverse organisms. Genome Biol Evol 2014; 6:1268-78. [PMID: 24812293 PMCID: PMC4079209 DOI: 10.1093/gbe/evu091] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Gene evolution is traditionally considered within the framework of the molecular clock (MC) model whereby each gene is characterized by an approximately constant rate of evolution. Recent comparative analysis of numerous phylogenies of prokaryotic genes has shown that a different model of evolution, denoted the Universal PaceMaker (UPM), which postulates conservation of relative, rather than absolute evolutionary rates, yields a better fit to the phylogenetic data. Here, we show that the UPM model is a better fit than the MC for genome wide sets of phylogenetic trees from six species of Drosophila and nine species of yeast, with extremely high statistical significance. Unlike the prokaryotic phylogenies that include distant organisms and multiple horizontal gene transfers, these are simple data sets that cover groups of closely related organisms and consist of gene trees with the same topology as the species tree. The results indicate that both lineage-specific and gene-specific rates are important in genome evolution but the lineage-specific contribution is greater. Similar to the MC, the gene evolution rates under the UPM are strongly overdispersed, approximately 2-fold compared with the expectation from sampling error alone. However, we show that neither Drosophila nor yeast genes form distinct clusters in the tree space. Thus, the gene-specific deviations from the UPM, although substantial, are uncorrelated and most likely depend on selective factors that are largely unique to individual genes. Thus, the UPM appears to be a key feature of genome evolution across the history of cellular life.
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Affiliation(s)
- Sagi Snir
- Department of Evolutionary and Environmental Biology and The Institute of Evolution, University of Haifa, Israel
| | - Yuri I Wolf
- National Center for Biotechnology Information, NLM, National Institutes of Health, Bethesda, MD
| | - Eugene V Koonin
- National Center for Biotechnology Information, NLM, National Institutes of Health, Bethesda, MD
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90
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Goldstein RA. Population size dependence of fitness effect distribution and substitution rate probed by biophysical model of protein thermostability. Genome Biol Evol 2014; 5:1584-93. [PMID: 23884461 PMCID: PMC3787666 DOI: 10.1093/gbe/evt110] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The predicted effect of effective population size on the distribution of fitness effects and substitution rate is critically dependent on the relationship between sequence and fitness. This highlights the importance of using models that are informed by the molecular biology, biochemistry, and biophysics of the evolving systems. We describe a computational model based on fundamental aspects of biophysics, the requirement for (most) proteins to be thermodynamically stable. Using this model, we find that differences in population size have minimal impact on the distribution of population-scaled fitness effects, as well as on the rate of molecular evolution. This is because larger populations result in selection for more stable proteins that are less affected by mutations. This reduction in the magnitude of the fitness effects almost exactly cancels the greater selective pressure resulting from the larger population size. Conversely, changes in the population size in either direction cause transient increases in the substitution rate. As differences in population size often correspond to changes in population size, this makes comparisons of substitution rates in different lineages difficult to interpret.
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Affiliation(s)
- Richard A Goldstein
- Division of Infection and Immunity, University College London, United Kingdom
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91
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Kaňuch P, Berggren A, Cassel-Lundhagen A. Genetic diversity of a successful colonizer: isolated populations of Metrioptera roeselii regain variation at an unusually rapid rate. Ecol Evol 2014; 4:1117-26. [PMID: 24772287 PMCID: PMC3997326 DOI: 10.1002/ece3.1005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 01/30/2014] [Indexed: 11/27/2022] Open
Abstract
Newly founded isolated populations need to overcome detrimental effects of low genetic diversity. The establishment success of a population may therefore depend on various mechanisms such as assortative mating, purging of deleterious alleles, creation of new mutations and/or repeated inflow of new genotypes to reduce the effects of inbreeding and further loss of genetic variation. We compared the level of genetic variation in introduced populations of an insect species (Metrioptera roeselii) far beyond its natural distribution with levels found in their respective founder populations and coupled the data with timing since establishment. This allowed us to analyze if the introduced populations showed signs of temporal changes in genetic variation and have made it possible to evaluate underlying mechanisms. For this, we used neutral genetic markers, seven microsatellite loci and a 676–bp-long sequence of the mtDNA COI gene. All tested indices (allelic richness, unbiased expected heterozygosity, effective size, haplotype diversity, and nucleotide diversity) except inbreeding coefficient had significantly higher values in populations within the founding populations inside the continuous area of the species distribution compared with the introduced populations. A logarithmic model showed a significant correlation of both allelic richness and unbiased expected heterozygosity with age of the isolated populations. Considering the species' inferred colonization history and likely introduction pathways, we suggest that multiple introductions are the main mechanism behind the temporal pattern observed. However, we argue that influences of assortative mating, directional selection, and effects of an exceptional high intrapopulation mutation rate may have impacts. The ability to regain genetic diversity at this level may be one of the main reasons why M. roeselii successfully continue to colonize northern Europe.
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Affiliation(s)
- Peter Kaňuch
- Department of Ecology, Swedish University of Agricultural Sciences Box 7044, 75007, Uppsala, Sweden ; Institute of Forest Ecology, Slovak Academy of Sciences Ľ. Štúra 2, 96053, Zvolen, Slovakia
| | - Asa Berggren
- Department of Ecology, Swedish University of Agricultural Sciences Box 7044, 75007, Uppsala, Sweden
| | - Anna Cassel-Lundhagen
- Department of Ecology, Swedish University of Agricultural Sciences Box 7044, 75007, Uppsala, Sweden
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92
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Weber CC, Boussau B, Romiguier J, Jarvis ED, Ellegren H. Evidence for GC-biased gene conversion as a driver of between-lineage differences in avian base composition. Genome Biol 2014; 15:549. [PMID: 25496599 PMCID: PMC4290106 DOI: 10.1186/s13059-014-0549-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 11/19/2014] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND While effective population size (Ne) and life history traits such as generation time are known to impact substitution rates, their potential effects on base composition evolution are less well understood. GC content increases with decreasing body mass in mammals, consistent with recombination-associated GC biased gene conversion (gBGC) more strongly impacting these lineages. However, shifts in chromosomal architecture and recombination landscapes between species may complicate the interpretation of these results. In birds, interchromosomal rearrangements are rare and the recombination landscape is conserved, suggesting that this group is well suited to assess the impact of life history on base composition. RESULTS Employing data from 45 newly and 3 previously sequenced avian genomes covering a broad range of taxa, we found that lineages with large populations and short generations exhibit higher GC content. The effect extends to both coding and non-coding sites, indicating that it is not due to selection on codon usage. Consistent with recombination driving base composition, GC content and heterogeneity were positively correlated with the rate of recombination. Moreover, we observed ongoing increases in GC in the majority of lineages. CONCLUSIONS Our results provide evidence that gBGC may drive patterns of nucleotide composition in avian genomes and are consistent with more effective gBGC in large populations and a greater number of meioses per unit time; that is, a shorter generation time. Thus, in accord with theoretical predictions, base composition evolution is substantially modulated by species life history.
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Affiliation(s)
- Claudia C Weber
- />Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
| | - Bastien Boussau
- />Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon, Université Lyon 1, CNRS, UMR5558 Villeurbanne, France
| | | | - Erich D Jarvis
- />Department of Neurobiology, Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC USA
| | - Hans Ellegren
- />Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36 Uppsala, Sweden
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93
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Abstract
Substitution rates vary between species, and many explanations regarding the causes of this variation have been proposed. Here we consider how new genomic data on the per-generation mutation rate impinge on proposed hypotheses for substitution rate variation in primates. We propose that the generation-time effect as it is usually understood cannot explain the observed rate variation, but instead that selection for decreased somatic mutation rates can. By considering the disparate causes underlying mutation rate changes in recent human history, we also show that the per-generation mutation rate is increasing even as the per-cell-division rate is decreasing.
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94
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Lanfear R, Kokko H, Eyre-Walker A. Population size and the rate of evolution. Trends Ecol Evol 2013; 29:33-41. [PMID: 24148292 DOI: 10.1016/j.tree.2013.09.009] [Citation(s) in RCA: 244] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 09/04/2013] [Accepted: 09/16/2013] [Indexed: 11/28/2022]
Abstract
Does evolution proceed faster in larger or smaller populations? The relationship between effective population size (Ne) and the rate of evolution has consequences for our ability to understand and interpret genomic variation, and is central to many aspects of evolution and ecology. Many factors affect the relationship between Ne and the rate of evolution, and recent theoretical and empirical studies have shown some surprising and sometimes counterintuitive results. Some mechanisms tend to make the relationship positive, others negative, and they can act simultaneously. The relationship also depends on whether one is interested in the rate of neutral, adaptive, or deleterious evolution. Here, we synthesize theoretical and empirical approaches to understanding the relationship and highlight areas that remain poorly understood.
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Affiliation(s)
- Robert Lanfear
- Ecology Evolution and Genetics, Research School of Biology, Australian National University, Canberra, ACT, Australia; National Evolutionary Synthesis Center, Durham, NC, USA.
| | - Hanna Kokko
- Ecology Evolution and Genetics, Research School of Biology, Australian National University, Canberra, ACT, Australia
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95
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Affiliation(s)
- Shane D. Wright
- School of Biological Sciences; University of Auckland; 22 Princes St; Auckland; 1010; New Zealand
| | - Klaus Rohde
- School of Environmental and Rural Sciences; University of New England; Elm Avenue; Armidale; NSW; 2351; Australia
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96
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Ezard THG, Thomas GH, Purvis A. Inclusion of a near-complete fossil record reveals speciation-related molecular evolution. Methods Ecol Evol 2013. [DOI: 10.1111/2041-210x.12089] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Thomas H. G. Ezard
- Centre for Biological Sciences; University of Southampton; Life Sciences Building 85, Highfield Campus; Southampton; SO17 1BJ; UK
| | - Gavin H. Thomas
- Department of Animal and Plant Sciences; University of Sheffield; Sheffield; S10 2TN; UK
| | - Andy Purvis
- Department of Life Sciences; Imperial College London; Silwood Park Campus; Ascot; Berkshire; SL5 7PY; UK
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97
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Okie JG, Boyer AG, Brown JH, Costa DP, Ernest SKM, Evans AR, Fortelius M, Gittleman JL, Hamilton MJ, Harding LE, Lintulaakso K, Lyons SK, Saarinen JJ, Smith FA, Stephens PR, Theodor J, Uhen MD, Sibly RM. Effects of allometry, productivity and lifestyle on rates and limits of body size evolution. Proc Biol Sci 2013; 280:20131007. [PMID: 23760865 DOI: 10.1098/rspb.2013.1007] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Body size affects nearly all aspects of organismal biology, so it is important to understand the constraints and dynamics of body size evolution. Despite empirical work on the macroevolution and macroecology of minimum and maximum size, there is little general quantitative theory on rates and limits of body size evolution. We present a general theory that integrates individual productivity, the lifestyle component of the slow-fast life-history continuum, and the allometric scaling of generation time to predict a clade's evolutionary rate and asymptotic maximum body size, and the shape of macroevolutionary trajectories during diversifying phases of size evolution. We evaluate this theory using data on the evolution of clade maximum body sizes in mammals during the Cenozoic. As predicted, clade evolutionary rates and asymptotic maximum sizes are larger in more productive clades (e.g. baleen whales), which represent the fast end of the slow-fast lifestyle continuum, and smaller in less productive clades (e.g. primates). The allometric scaling exponent for generation time fundamentally alters the shape of evolutionary trajectories, so allometric effects should be accounted for in models of phenotypic evolution and interpretations of macroevolutionary body size patterns. This work highlights the intimate interplay between the macroecological and macroevolutionary dynamics underlying the generation and maintenance of morphological diversity.
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Affiliation(s)
- Jordan G Okie
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA.
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98
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Dowle EJ, Morgan-Richards M, Trewick SA. Molecular evolution and the latitudinal biodiversity gradient. Heredity (Edinb) 2013; 110:501-10. [PMID: 23486082 PMCID: PMC3656639 DOI: 10.1038/hdy.2013.4] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 12/18/2012] [Accepted: 01/08/2013] [Indexed: 12/13/2022] Open
Abstract
Species density is higher in the tropics (low latitude) than in temperate regions (high latitude) resulting in a latitudinal biodiversity gradient (LBG). The LBG must be generated by differential rates of speciation and/or extinction and/or immigration among regions, but the role of each of these processes is still unclear. Recent studies examining differences in rates of molecular evolution have inferred a direct link between rate of molecular evolution and rate of speciation, and postulated these as important drivers of the LBG. Here we review the molecular genetic evidence and examine the factors that might be responsible for differences in rates of molecular evolution. Critical to this is the directionality of the relationship between speciation rates and rates of molecular evolution.
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Affiliation(s)
- E J Dowle
- Massey University, Palmerston North, New Zealand.
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99
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Taller plants have lower rates of molecular evolution. Nat Commun 2013; 4:1879. [DOI: 10.1038/ncomms2836] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 04/05/2013] [Indexed: 01/20/2023] Open
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100
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