1
|
McDaniel SF. Local adaptation, recombination, and the fate of neopolyploids. THE NEW PHYTOLOGIST 2024; 244:32-38. [PMID: 39045612 DOI: 10.1111/nph.20011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Accepted: 07/09/2024] [Indexed: 07/25/2024]
Abstract
Polyploidy is widely recognized as an important speciation mechanism because it isolates tetraploids from their diploid progenitors. Polyploidy also provides new genetic material that may facilitate adaptive evolution. However, new mutations are more likely to arise after a neopolyploid has already successfully invaded a population. Thus, the role of adaptive forces in establishing a polyploid remains unclear. One solution to this apparent paradox may lie in the capacity of polyploids to suppress recombination among preexisting locally adapted alleles. The local adaptation mechanism requires that spatially heterogeneous selection acts on multiple loci and that gene flow introduces maladapted alleles to the population where the polyploid forms. The mechanism requires neither strong genetic drift nor any intrinsic benefit of genome doubling and can accommodate any mode of gene action. A unique prediction of the mechanism is that adaptive alleles should predate polyploidization, a pattern consistent with observations from a few well-studied polyploids. The mechanism is also consistent with the coexistence of both diploid and tetraploid cytotypes, fitness heterogeneity among independently derived polyploids, and the prevalence of outcrossing among older polyploids. The local adaptation mechanism also makes novel predictions about circumstances favoring polyploid invasions that can be tested using molecular genetic or comparative approaches.
Collapse
Affiliation(s)
- Stuart F McDaniel
- Department of Biology, University of Florida, Gainesville, FL, 32611, USA
| |
Collapse
|
2
|
Dopman EB, Shaw KL, Servedio MR, Butlin RK, Smadja CM. Coupling of Barriers to Gene Exchange: Causes and Consequences. Cold Spring Harb Perspect Biol 2024; 16:a041432. [PMID: 38191516 PMCID: PMC11293547 DOI: 10.1101/cshperspect.a041432] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
Coupling has emerged as a concept to describe the transition from differentiated populations to newly evolved species through the strengthening of reproductive isolation. However, the term has been used in multiple ways, and relevant processes have sometimes not been clearly distinguished. Here, we synthesize existing uses of the concept of coupling and find three main perspectives: (1) coupling as the build-up of linkage disequilibrium among loci underlying barriers to gene exchange, (2) coupling as the build-up of genome-wide linkage disequilibrium, and (3) coupling as the process generating a coincidence of distinct barrier effects. We compare and contrast these views, show the diverse processes involved and the complexity of the relationships among recombination, linkage disequilibrium, and reproductive isolation, and, finally, we emphasize how each perspective can guide new directions in speciation research. Although the importance of coupling for evolutionary divergence and speciation is well established, many theoretical and empirical questions remain unanswered.
Collapse
Affiliation(s)
- Erik B Dopman
- Department of Biology, Tufts University, Medford, Massachusetts 02155, USA
| | - Kerry L Shaw
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853, USA
| | - Maria R Servedio
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Roger K Butlin
- Ecology and Evolutionary Biology, School of Biosciences, The University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
- Department of Marine Sciences, University of Gothenburg, Gothenburg 40530, Sweden
| | - Carole M Smadja
- Institut des Sciences de l'Evolution de Montpellier ISEM, Universite de Montpellier, CNRS, IRD, Montpellier 34095, France
| |
Collapse
|
3
|
Wright CJ, Stevens L, Mackintosh A, Lawniczak M, Blaxter M. Comparative genomics reveals the dynamics of chromosome evolution in Lepidoptera. Nat Ecol Evol 2024; 8:777-790. [PMID: 38383850 PMCID: PMC11009112 DOI: 10.1038/s41559-024-02329-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 01/12/2024] [Indexed: 02/23/2024]
Abstract
Chromosomes are a central unit of genome organization. One-tenth of all described species on Earth are butterflies and moths, the Lepidoptera, which generally possess 31 chromosomes. However, some species display dramatic variation in chromosome number. Here we analyse 210 chromosomally complete lepidopteran genomes and show that the chromosomes of extant lepidopterans are derived from 32 ancestral linkage groups, which we term Merian elements. Merian elements have remained largely intact through 250 million years of evolution and diversification. Against this stable background, eight lineages have undergone extensive reorganization either through numerous fissions or a combination of fusion and fission events. Outside these lineages, fusions are rare and fissions are rarer still. Fusions often involve small, repeat-rich Merian elements and the sex-linked element. Our results reveal the constraints on genome architecture in Lepidoptera and provide a deeper understanding of chromosomal rearrangements in eukaryotic genome evolution.
Collapse
Affiliation(s)
| | - Lewis Stevens
- Tree of Life, Wellcome Sanger Institute, Cambridge, UK
| | | | | | - Mark Blaxter
- Tree of Life, Wellcome Sanger Institute, Cambridge, UK.
| |
Collapse
|
4
|
Slowinski SP, Gresham JD, Cui ER, Haspel K, Lively CM, Morran LT. Outcrossing in Caenorhabditis elegans increases in response to food limitation. Ecol Evol 2024; 14:e11166. [PMID: 38516572 PMCID: PMC10954511 DOI: 10.1002/ece3.11166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 02/05/2024] [Accepted: 02/29/2024] [Indexed: 03/23/2024] Open
Abstract
Theory predicts that organisms should diversify their offspring when faced with a stressful environment. This prediction has received empirical support across diverse groups of organisms and stressors. For example, when encountered by Caenorhabditis elegans during early development, food limitation (a common environmental stressor) induces the nematodes to arrest in a developmental stage called dauer and to increase their propensity to outcross when they are subsequently provided with food and enabled to develop to maturity. Here we tested whether food limitation first encountered during late development/early adulthood can also induce increased outcrossing propensity in C. elegans. Previously well-fed C. elegans increased their propensity to outcross when challenged with food limitation during the final larval stage of development and into early adulthood, relative to continuously well-fed (control) nematodes. Our results thus support previous research demonstrating that the stress of food limitation can induce increased outcrossing propensity in C. elegans. Furthermore, our results expand on previous work by showing that food limitation can still increase outcrossing propensity even when it is not encountered until late development, and this can occur independently of the developmental and gene expression changes associated with dauer.
Collapse
Affiliation(s)
- Samuel P. Slowinski
- Department of BiologyIndiana UniversityBloomingtonIndianaUSA
- Department BiologyUniversity of MarylandCollege ParkMarylandUSA
| | | | - Eric R. Cui
- Department of BiologyIndiana UniversityBloomingtonIndianaUSA
| | | | | | | |
Collapse
|
5
|
Jay P, Aubier TG, Joron M. The interplay of local adaptation and gene flow may lead to the formation of supergenes. Mol Ecol 2024:e17297. [PMID: 38415327 DOI: 10.1111/mec.17297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 12/28/2023] [Accepted: 01/10/2024] [Indexed: 02/29/2024]
Abstract
Supergenes are genetic architectures resulting in the segregation of alternative combinations of alleles underlying complex phenotypes. The co-segregation of alleles at linked loci is often facilitated by polymorphic chromosomal rearrangements suppressing recombination locally. Supergenes are involved in many complex polymorphisms, including sexual, colour or behavioural polymorphisms in numerous plants, fungi, mammals, fish, and insects. Despite a long history of empirical and theoretical research, the formation of supergenes remains poorly understood. Here, using a two-island population genetic model, we explore how gene flow and the evolution of overdominant chromosomal inversions may jointly lead to the formation of supergenes. We show that the evolution of inversions in differentiated populations, both under disruptive selection, leads to an increase in frequency of poorly adapted, immigrant haplotypes. Indeed, rare allelic combinations, such as immigrant haplotypes, are more frequently reshuffled by recombination than common allelic combinations, and therefore benefit from the recombination suppression generated by inversions. When an inversion capturing a locally adapted haplotype spreads but is associated with a fitness cost hampering its fixation (e.g. a recessive mutation load), the maintenance of a non-inverted haplotype in the population is enhanced; under certain conditions, the immigrant haplotype persists alongside the inverted local haplotype, while the standard local haplotype disappears. This establishes a stable, local polymorphism with two non-recombining haplotypes encoding alternative adaptive strategies, that is, a supergene. These results bring new light to the importance of local adaptation, overdominance, and gene flow in the formation of supergenes and inversion polymorphisms in general.
Collapse
Affiliation(s)
- Paul Jay
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), Université de Montpellier, CNRS, EPHE, IRD, Montpellier, France
- Center for GeoGenetics, University of Copenhagen, Copenhagen, Denmark
| | - Thomas G Aubier
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, USA
- Centre de Recherche sur la Biodiversité et l'Environnement (CRBE), Université de Toulouse, CNRS, IRD, Toulouse INP, Université Toulouse 3 - Paul Sabatier (UT3), Toulouse, France
| | - Mathieu Joron
- Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), Université de Montpellier, CNRS, EPHE, IRD, Montpellier, France
| |
Collapse
|
6
|
James ME, Ortiz-Barrientos D. The genomic consequences of selection across development. Mol Ecol 2024; 33:e17280. [PMID: 38247305 DOI: 10.1111/mec.17280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/01/2024] [Accepted: 01/12/2024] [Indexed: 01/23/2024]
Abstract
Understanding how natural selection drives diversification in nature has been at the forefront of biological research for over a century. The main idea is simple: natural selection favours individuals best suited to pass on their genes. However, the journey from birth to reproduction is complex as organisms experience multiple developmental stages, each influenced by genetic and environmental factors (Orr, 2009). These complexities compound even further as each stage of development might be governed by a unique underlying set of alleles and genes. In this issue of Molecular Ecology, Goebl et al. (2022) examine the role of natural selection in driving ecotypic divergence across different life history stages of the prairie sunflower Helianthus petiolaris. The authors used reciprocal transplant experiments, demographic models, and genomic sequencing to explore fitness variation across developmental stages. They show how natural selection impacts population divergence across multiple life history stages and evaluate the resulting allele frequency changes. Goebl et al. link these results to the role of chromosomal inversions, thus furthering our understanding of how ecological divergence proceeds in the face of gene flow. Below, we explore these results in detail and complement their interpretation by considering the evolution of genetic correlations amongst traits governing fitness.
Collapse
Affiliation(s)
- Maddie E James
- School of the Environment, The University of Queensland, St Lucia, QLD, Australia
- Australian Research Council Centre of Excellence for Plant Success in Nature and Agriculture, St Lucia, QLD, Australia
| | - Daniel Ortiz-Barrientos
- School of the Environment, The University of Queensland, St Lucia, QLD, Australia
- Australian Research Council Centre of Excellence for Plant Success in Nature and Agriculture, St Lucia, QLD, Australia
| |
Collapse
|
7
|
Wong ELY, Filatov DA. The role of recombination landscape in species hybridisation and speciation. FRONTIERS IN PLANT SCIENCE 2023; 14:1223148. [PMID: 37484464 PMCID: PMC10361763 DOI: 10.3389/fpls.2023.1223148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 06/13/2023] [Indexed: 07/25/2023]
Abstract
It is now well recognised that closely related species can hybridize and exchange genetic material, which may promote or oppose adaptation and speciation. In some cases, interspecific hybridisation is very common, making it surprising that species identity is preserved despite active gene exchange. The genomes of most eukaryotic species are highly heterogeneous with regard to gene density, abundance of repetitive DNA, chromatin compactisation etc, which can make certain genomic regions more prone or more resistant to introgression of genetic material from other species. Heterogeneity in local recombination rate underpins many of the observed patterns across the genome (e.g. actively recombining regions are typically gene rich and depleted for repetitive DNA) and it can strongly affect the permeability of genomic regions to interspecific introgression. The larger the region lacking recombination, the higher the chance for the presence of species incompatibility gene(s) in that region, making the entire non- or rarely recombining block impermeable to interspecific introgression. Large plant genomes tend to have highly heterogeneous recombination landscape, with recombination frequently occurring at the ends of the chromosomes and central regions lacking recombination. In this paper we review the relationship between recombination and introgression in plants and argue that large rarely recombining regions likely play a major role in preserving species identity in actively hybridising plant species.
Collapse
Affiliation(s)
- Edgar L. Y. Wong
- Department of Biology, University of Oxford, Oxford, United Kingdom
- Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
| | | |
Collapse
|
8
|
Prapas D, Scalone R, Lee J, Nurkowski KA, Bou‐assi S, Rieseberg L, Battlay P, Hodgins KA. Quantitative trait loci mapping reveals an oligogenic architecture of a rapidly adapting trait during the European invasion of common ragweed. Evol Appl 2022; 15:1249-1263. [PMID: 36051461 PMCID: PMC9423086 DOI: 10.1111/eva.13453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 06/05/2022] [Accepted: 06/30/2022] [Indexed: 01/09/2023] Open
Abstract
Biological invasions offer a unique opportunity to investigate evolution over contemporary timescales. Rapid adaptation to local climates during range expansion can be a major determinant of invasion success, yet fundamental questions remain about its genetic basis. This study sought to investigate the genetic basis of climate adaptation in invasive common ragweed (Ambrosia artemisiifolia). Flowering time adaptation is key to this annual species' invasion success, so much so that it has evolved repeated latitudinal clines in size and phenology across its native and introduced ranges despite high gene flow among populations. Here, we produced a high-density linkage map (4493 SNPs) and paired this with phenotypic data from an F2 mapping population (n = 336) to identify one major and two minor quantitative trait loci (QTL) underlying flowering time and height differentiation in this species. Within each QTL interval, several candidate flowering time genes were also identified. Notably, the major flowering time QTL detected in this study was found to overlap with a previously identified haploblock (putative inversion). Multiple genetic maps of this region identified evidence of suppressed recombination in specific genotypes, consistent with inversions. These discoveries support the expectation that a concentrated genetic architecture with fewer, larger, and more tightly linked alleles should underlie rapid local adaptation during invasion, particularly when divergently adapting populations experience high levels of gene flow.
Collapse
Affiliation(s)
- Diana Prapas
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Romain Scalone
- Department of Crop Production Ecology, Uppsala Ecology CenterSwedish University of Agricultural SciencesUppsalaSweden
- Department of Grapevine BreedingHochschule Geisenheim UniversityGeisenheimGermany
| | - Jacqueline Lee
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Kristin A. Nurkowski
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
- Department of Botany and Biodiversity Research CentreUniversity of British ColumbiaVancouverCanada
| | - Sarah Bou‐assi
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Loren Rieseberg
- Department of Botany and Biodiversity Research CentreUniversity of British ColumbiaVancouverCanada
| | - Paul Battlay
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Kathryn A. Hodgins
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
| |
Collapse
|
9
|
Jay P, Leroy M, Le Poul Y, Whibley A, Arias M, Chouteau M, Joron M. Association mapping of colour variation in a butterfly provides evidence that a supergene locks together a cluster of adaptive loci. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210193. [PMID: 35694756 PMCID: PMC9189503 DOI: 10.1098/rstb.2021.0193] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Supergenes are genetic architectures associated with discrete and concerted variation in multiple traits. It has long been suggested that supergenes control these complex polymorphisms by suppressing recombination between sets of coadapted genes. However, because recombination suppression hinders the dissociation of the individual effects of genes within supergenes, there is still little evidence that supergenes evolve by tightening linkage between coadapted genes. Here, combining a landmark-free phenotyping algorithm with multivariate genome-wide association studies, we dissected the genetic basis of wing pattern variation in the butterfly Heliconius numata. We show that the supergene controlling the striking wing pattern polymorphism displayed by this species contains several independent loci associated with different features of wing patterns. The three chromosomal inversions of this supergene suppress recombination between these loci, supporting the hypothesis that they may have evolved because they captured beneficial combinations of alleles. Some of these loci are, however, associated with colour variations only in a subset of morphs where the phenotype is controlled by derived inversion forms, indicating that they were recruited after the formation of the inversions. Our study shows that supergenes and clusters of adaptive loci in general may form via the evolution of chromosomal rearrangements suppressing recombination between co-adapted loci but also via the subsequent recruitment of linked adaptive mutations. This article is part of the theme issue 'Genomic architecture of supergenes: causes and evolutionary consequences'.
Collapse
Affiliation(s)
- Paul Jay
- CEFE, Université de Montpellier, CNRS, EPHE, IRD, 34293 Montpellier cedex 5, France
| | - Manon Leroy
- CEFE, Université de Montpellier, CNRS, EPHE, IRD, 34293 Montpellier cedex 5, France
| | - Yann Le Poul
- CEFE, Université de Montpellier, CNRS, EPHE, IRD, 34293 Montpellier cedex 5, France
| | - Annabel Whibley
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
| | - Mónica Arias
- CIRAD, UMR PHIM, F-34398 Montpellier, France.,PHIM, Univ Montpellier, CIRAD, INRAE, Institut Agro, IRD, CEDEX 5, 34398 Montpellier, France
| | - Mathieu Chouteau
- CEFE, Université de Montpellier, CNRS, EPHE, IRD, 34293 Montpellier cedex 5, France.,LEEISA, USR 63456, Université de Guyane, CNRS, IFREMER, 275 route de Montabo, 797334 Cayenne, French Guiana
| | - Mathieu Joron
- CEFE, Université de Montpellier, CNRS, EPHE, IRD, 34293 Montpellier cedex 5, France
| |
Collapse
|
10
|
Abstract
The rediscovery of Mendel’s work showing that the heredity of phenotypes is controlled by discrete genes was followed by the reconciliation of Mendelian genetics with evolution by natural selection in the middle of the last century with the Modern Synthesis. In the past two decades, dramatic advances in genomic methods have facilitated the identification of the loci, genes, and even individual mutations that underlie phenotypic variants that are the putative targets of natural selection. Moreover, these methods have also changed how we can study adaptation by flipping the problem around, allowing us to first examine what loci show evidence of having been under selection, and then connecting these genetic variants to phenotypic variation. As a result, we now have an expanding list of actual genetic changes that underlie potentially adaptive phenotypic variation. Here, we synthesize how considering the effects of these adaptive loci in the context of cellular environments, genomes, organisms, and populations has provided new insights to the genetic architecture of adaptation.
Collapse
|
11
|
Chasing genetic correlation breakers to stimulate population resilience to climate change. Sci Rep 2022; 12:8238. [PMID: 35581288 PMCID: PMC9114142 DOI: 10.1038/s41598-022-12320-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 05/09/2022] [Indexed: 11/29/2022] Open
Abstract
Global climate change introduces new combinations of environmental conditions, which is expected to increase stress on plants. This could affect many traits in multiple ways that are as yet unknown but will likely require the modification of existing genetic relationships among functional traits potentially involved in local adaptation. Theoretical evolutionary studies have determined that it is an advantage to have an excess of recombination events under heterogeneous environmental conditions. Our study, conducted on a population of radiata pine (Pinus radiata D. Don), was able to identify individuals that show high genetic recombination at genomic regions, which potentially include pleiotropic or collocating QTLs responsible for the studied traits, reaching a prediction accuracy of 0.80 in random cross-validation and 0.72 when whole family was removed from the training population and predicted. To identify these highly recombined individuals, a training population was constructed from correlation breakers, created through tandem selection of parents in the previous generation and their consequent mating. Although the correlation breakers showed lower observed heterogeneity possibly due to direct selection in both studied traits, the genomic regions with statistically significant differences in the linkage disequilibrium pattern showed higher level of heretozygosity, which has the effect of decomposing unfavourable genetic correlation. We propose undertaking selection of correlation breakers under current environmental conditions and using genomic predictions to increase the frequency of these ’recombined’ individuals in future plantations, ensuring the resilience of planted forests to changing climates. The increased frequency of such individuals will decrease the strength of the population-level genetic correlations among traits, increasing the opportunity for new trait combinations to be developed in the future.
Collapse
|
12
|
Curtin S, Qi Y, Peres LEP, Fernie AR, Zsögön A. Pathways to de novo domestication of crop wild relatives. PLANT PHYSIOLOGY 2022; 188:1746-1756. [PMID: 34850221 PMCID: PMC8968405 DOI: 10.1093/plphys/kiab554] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/03/2021] [Indexed: 05/24/2023]
Abstract
Growing knowledge about crop domestication, combined with increasingly powerful gene-editing toolkits, sets the stage for the continual domestication of crop wild relatives and other lesser-known plant species.
Collapse
Affiliation(s)
- Shaun Curtin
- United States Department of Agriculture, Plant Science Research Unit, St. Paul, Minnesota 55108, USA
- Center for Plant Precision Genomics, University of Minnesota, St. Paul, Minnesota 55108, USA
- Center for Genome Engineering, University of Minnesota, St. Paul, Minnesota 55108, USA
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108, USA
| | - Yiping Qi
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland, USA
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland, USA
| | - Lázaro E P Peres
- Laboratory of Hormonal Control of Plant Development. Departamento de Ciências Biológicas, Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo, CP 09, 13418-900, Piracicaba, São Paulo, Brazil
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | | |
Collapse
|
13
|
Eriksson M, Rafajlović M. The role of phenotypic plasticity in the establishment of range margins. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210012. [PMID: 35067091 PMCID: PMC8784930 DOI: 10.1098/rstb.2021.0012] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 11/16/2021] [Indexed: 12/15/2022] Open
Abstract
It has been argued that adaptive phenotypic plasticity may facilitate range expansions over spatially and temporally variable environments. However, plasticity may induce fitness costs. This may hinder the evolution of plasticity. Earlier modelling studies examined the role of plasticity during range expansions of populations with fixed genetic variance. However, genetic variance evolves in natural populations. This may critically alter model outcomes. We ask: how does the capacity for plasticity in populations with evolving genetic variance alter range margins that populations without the capacity for plasticity are expected to attain? We answered this question using computer simulations and analytical approximations. We found a critical plasticity cost above which the capacity for plasticity has no impact on the expected range of the population. Below the critical cost, by contrast, plasticity facilitates range expansion, extending the range in comparison to that expected for populations without plasticity. We further found that populations may evolve plasticity to buffer temporal environmental fluctuations, but only when the plasticity cost is below the critical cost. Thus, the cost of plasticity is a key factor involved in range expansions of populations with the potential to express plastic response in the adaptive trait. This article is part of the theme issue 'Species' ranges in the face of changing environments (part I)'.
Collapse
Affiliation(s)
- Martin Eriksson
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
- The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
- Gothenburg Global Biodiversity Centre, University of Gothenburg, Gothenburg, Sweden
| | - Marina Rafajlović
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
- The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
| |
Collapse
|
14
|
Yeaman S. Evolution of polygenic traits under global vs local adaptation. Genetics 2022; 220:iyab134. [PMID: 35134196 PMCID: PMC8733419 DOI: 10.1093/genetics/iyab134] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/05/2021] [Indexed: 12/14/2022] Open
Abstract
Observations about the number, frequency, effect size, and genomic distribution of alleles associated with complex traits must be interpreted in light of evolutionary process. These characteristics, which constitute a trait's genetic architecture, can dramatically affect evolutionary outcomes in applications from agriculture to medicine, and can provide a window into how evolution works. Here, I review theoretical predictions about the evolution of genetic architecture under spatially homogeneous, global adaptation as compared with spatially heterogeneous, local adaptation. Due to the tension between divergent selection and migration, local adaptation can favor "concentrated" genetic architectures that are enriched for alleles of larger effect, clustered in a smaller number of genomic regions, relative to expectations under global adaptation. However, the evolution of such architectures may be limited by many factors, including the genotypic redundancy of the trait, mutation rate, and temporal variability of environment. I review the circumstances in which predictions differ for global vs local adaptation and discuss where progress can be made in testing hypotheses using data from natural populations and lab experiments. As the field of comparative population genomics expands in scope, differences in architecture among traits and species will provide insights into how evolution works, and such differences must be interpreted in light of which kind of selection has been operating.
Collapse
Affiliation(s)
- Sam Yeaman
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| |
Collapse
|
15
|
Liu Z, Roesti M, Marques D, Hiltbrunner M, Saladin V, Peichel CL. Chromosomal fusions facilitate adaptation to divergent environments in threespine stickleback. Mol Biol Evol 2021; 39:6462204. [PMID: 34908155 PMCID: PMC8826639 DOI: 10.1093/molbev/msab358] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Chromosomal fusions are hypothesized to facilitate adaptation to divergent environments, both by bringing together previously unlinked adaptive alleles and by creating regions of low recombination that facilitate the linkage of adaptive alleles; but, there is little empirical evidence to support this hypothesis. Here, we address this knowledge gap by studying threespine stickleback (Gasterosteus aculeatus), in which ancestral marine fish have repeatedly adapted to freshwater across the northern hemisphere. By comparing the threespine and ninespine stickleback (Pungitius pungitius) genomes to a de novo assembly of the fourspine stickleback (Apeltes quadracus) and an outgroup species, we find two chromosomal fusion events involving the same chromosomes have occurred independently in the threespine and ninespine stickleback lineages. On the fused chromosomes in threespine stickleback, we find an enrichment of quantitative trait loci underlying traits that contribute to marine versus freshwater adaptation. By comparing whole-genome sequences of freshwater and marine threespine stickleback populations, we also find an enrichment of regions under divergent selection on these two fused chromosomes. There is elevated genetic diversity within regions under selection in the freshwater population, consistent with a simulation study showing that gene flow can increase diversity in genomic regions associated with local adaptation and our demographic models showing gene flow between the marine and freshwater populations. Integrating our results with previous studies, we propose that these fusions created regions of low recombination that enabled the formation of adaptative clusters, thereby facilitating freshwater adaptation in the face of recurrent gene flow between marine and freshwater threespine sticklebacks.
Collapse
Affiliation(s)
- Zuyao Liu
- Division of Evolutionary Ecology, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
| | - Marius Roesti
- Division of Evolutionary Ecology, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
| | - David Marques
- Division of Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland.,Department of Fish Ecology and Evolution, Centre for Ecology, Evolution, and Biogeochemistry, Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Kastanienbaum, Switzerland.,Natural History Museum Basel, Basel, Switzerland
| | - Melanie Hiltbrunner
- Division of Evolutionary Ecology, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
| | - Verena Saladin
- Division of Evolutionary Ecology, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
| | - Catherine L Peichel
- Division of Evolutionary Ecology, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
| |
Collapse
|
16
|
Malinovskaya LP, Tishakova KV, Bikchurina TI, Slobodchikova AY, Torgunakov NY, Torgasheva AA, Tsepilov YA, Volkova NA, Borodin PM. Negative heterosis for meiotic recombination rate in spermatocytes of the domestic chicken Gallus gallus. Vavilovskii Zhurnal Genet Selektsii 2021; 25:661-668. [PMID: 34782886 PMCID: PMC8558918 DOI: 10.18699/vj21.075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 11/24/2022] Open
Abstract
Benef its and costs of meiotic recombination are a matter of discussion. Because recombination breaks
allele combinations already tested by natural selection and generates new ones of unpredictable f itness, a high
recombination rate is generally benef icial for the populations living in a f luctuating or a rapidly changing environment
and costly in a stable environment. Besides genetic benef its and costs, there are cytological effects of recombination,
both positive and negative. Recombination is necessary for chromosome synapsis and segregation. However,
it involves a massive generation of double-strand DNA breaks, erroneous repair of which may lead to germ
cell death or various mutations and chromosome rearrangements. Thus, the benef its of recombination (generation
of new allele combinations) would prevail over its costs (occurrence of deleterious mutations) as long as the population
remains suff iciently heterogeneous. Using immunolocalization of MLH1, a mismatch repair protein, at the
synaptonemal complexes, we examined the number and distribution of recombination nodules in spermatocytes
of two chicken breeds with high (Pervomai) and low (Russian Crested) recombination rates and their F1 hybrids and
backcrosses. We detected negative heterosis for recombination rate in the F1 hybrids. Backcrosses to the Pervomai
breed were rather homogenous and showed an intermediate recombination rate. The differences in overall recombination
rate between the breeds, hybrids and backcrosses were mainly determined by the differences in the crossing
over number in the seven largest macrochromosomes. The decrease in recombination rate in F1 is probably
determined by diff iculties in homology matching between the DNA sequences of genetically divergent breeds. The
suppression of recombination in the hybrids may impede gene f low between parapatric populations and therefore
accelerate their genetic divergence.
Collapse
Affiliation(s)
- L P Malinovskaya
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | | | - T I Bikchurina
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - A Yu Slobodchikova
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - N Yu Torgunakov
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - A A Torgasheva
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Y A Tsepilov
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - N A Volkova
- L.K. Ernst Federal Research Center for Animal Husbandry, Dubrovitsy, Moscow region, Russia
| | - P M Borodin
- Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| |
Collapse
|
17
|
Neupane S, Xu S. Adaptive Divergence of Meiotic Recombination Rate in Ecological Speciation. Genome Biol Evol 2021; 12:1869-1881. [PMID: 32857858 PMCID: PMC7594247 DOI: 10.1093/gbe/evaa182] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2020] [Indexed: 02/06/2023] Open
Abstract
Theories predict that directional selection during adaptation to a novel habitat results in elevated meiotic recombination rate. Yet the lack of population-level recombination rate data leaves this hypothesis untested in natural populations. Here, we examine the population-level recombination rate variation in two incipient ecological species, the microcrustacean Daphnia pulex (an ephemeral-pond species) and Daphnia pulicaria (a permanent-lake species). The divergence of D. pulicaria from D. pulex involved habitat shifts from pond to lake habitats as well as strong local adaptation due to directional selection. Using a novel single-sperm genotyping approach, we estimated the male-specific recombination rate of two linkage groups in multiple populations of each species in common garden experiments and identified a significantly elevated recombination rate in D. pulicaria. Most importantly, population genetic analyses show that the divergence in recombination rate between these two species is most likely due to divergent selection in distinct ecological habitats rather than neutral evolution.
Collapse
Affiliation(s)
| | - Sen Xu
- Department of Biology, University of Texas at Arlington
| |
Collapse
|
18
|
Mérot C, Berdan EL, Cayuela H, Djambazian H, Ferchaud AL, Laporte M, Normandeau E, Ragoussis J, Wellenreuther M, Bernatchez L. Locally Adaptive Inversions Modulate Genetic Variation at Different Geographic Scales in a Seaweed Fly. Mol Biol Evol 2021; 38:3953-3971. [PMID: 33963409 PMCID: PMC8382925 DOI: 10.1093/molbev/msab143] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Across a species range, multiple sources of environmental heterogeneity, at both small and large scales, create complex landscapes of selection, which may challenge adaptation, particularly when gene flow is high. One key to multidimensional adaptation may reside in the heterogeneity of recombination along the genome. Structural variants, like chromosomal inversions, reduce recombination, increasing linkage disequilibrium among loci at a potentially massive scale. In this study, we examined how chromosomal inversions shape genetic variation across a species range and ask how their contribution to adaptation in the face of gene flow varies across geographic scales. We sampled the seaweed fly Coelopa frigida along a bioclimatic gradient stretching across 10° of latitude, a salinity gradient, and a range of heterogeneous, patchy habitats. We generated a chromosome-level genome assembly to analyze 1,446 low-coverage whole genomes collected along those gradients. We found several large nonrecombining genomic regions, including putative inversions. In contrast to the collinear regions, inversions and low-recombining regions differentiated populations more strongly, either along an ecogeographic cline or at a fine-grained scale. These genomic regions were associated with environmental factors and adaptive phenotypes, albeit with contrasting patterns. Altogether, our results highlight the importance of recombination in shaping adaptation to environmental heterogeneity at local and large scales.
Collapse
Affiliation(s)
- Claire Mérot
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Canada
| | - Emma L Berdan
- Department of Ecology, Environment and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Hugo Cayuela
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Canada
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | | | - Anne-Laure Ferchaud
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Canada
| | - Martin Laporte
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Canada
| | - Eric Normandeau
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Canada
| | | | - Maren Wellenreuther
- Seafood Research Unit, Plant & Food Research, Port Nelson, Nelson, New Zealand
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Louis Bernatchez
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Canada
| |
Collapse
|
19
|
McLeod DV, Gandon S. Understanding the evolution of multiple drug resistance in structured populations. eLife 2021; 10:65645. [PMID: 34061029 PMCID: PMC8208818 DOI: 10.7554/elife.65645] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 05/28/2021] [Indexed: 12/19/2022] Open
Abstract
The evolution of multidrug resistance (MDR) is a pressing public health concern. Yet many aspects, such as the role played by population structure, remain poorly understood. Here, we argue that studying MDR evolution by focusing upon the dynamical equations for linkage disequilibrium (LD) can greatly simplify the calculations, generate more insight, and provide a unified framework for understanding the role of population structure. We demonstrate how a general epidemiological model of MDR evolution can be recast in terms of the LD equations. These equations reveal how the different forces generating and propagating LD operate in a dynamical setting at both the population and metapopulation levels. We then apply these insights to show how the LD perspective: (i) explains equilibrium patterns of MDR, (ii) provides a simple interpretative framework for transient evolutionary dynamics, and (iii) can be used to assess the consequences of different drug prescription strategies for MDR evolution.
Collapse
Affiliation(s)
- David V McLeod
- Centre D'Ecologie Fonctionnelle & Evolutive, CNRS, Univ Montpellier, EPHE, IRD, Montpellier, France
| | - Sylvain Gandon
- Centre D'Ecologie Fonctionnelle & Evolutive, CNRS, Univ Montpellier, EPHE, IRD, Montpellier, France
| |
Collapse
|
20
|
Fouqueau L, Roze D. The evolution of sex along an environmental gradient. Evolution 2021; 75:1334-1347. [PMID: 33901319 DOI: 10.1111/evo.14237] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 03/28/2021] [Indexed: 11/28/2022]
Abstract
Although temporally changing environments generally favor sex and recombination, the effects of spatial environmental heterogeneity have been less explored. In this article, we use a classical model of adaptation along with an environmental gradient to study the selective forces acting on reproductive mode evolution in the central and marginal parts of the distribution range of a species. The model considers a polygenic trait under stabilizing selection (the optimal trait value changing across space) and includes a demographic component imposing range limits. The results show that in the central part of the range (where populations are well adapted), recombination tends to increase the mean fitness of offspring in regimes where drift is sufficiently strong (generating a benefit for sex), while it has the opposite effect when the effect of drift stays negligible. However, these effects remain weak and are easily overwhelmed by slight intrinsic fitness differences between sexuals and asexuals. In agreement with previous results, asexuality may be favored in marginal populations, as it can preserve adaptation to extreme conditions. However, a substantial advantage of asexuality is possible only in conditions maintaining a strong maladaptation of sexuals at range limits (high effective environmental gradient, weak selection at loci coding for the trait).
Collapse
Affiliation(s)
- Louise Fouqueau
- Evolutionary Biology and Ecology of Algae, IRL 3614, CNRS, Station Biologique de Roscoff, Roscoff, 29688, France.,Station Biologique de Roscoff, Sorbonne Université, Roscoff, 29688, France
| | - Denis Roze
- Evolutionary Biology and Ecology of Algae, IRL 3614, CNRS, Station Biologique de Roscoff, Roscoff, 29688, France.,Station Biologique de Roscoff, Sorbonne Université, Roscoff, 29688, France
| |
Collapse
|
21
|
Koch EL, Morales HE, Larsson J, Westram AM, Faria R, Lemmon AR, Lemmon EM, Johannesson K, Butlin RK. Genetic variation for adaptive traits is associated with polymorphic inversions in Littorina saxatilis. Evol Lett 2021; 5:196-213. [PMID: 34136269 PMCID: PMC8190449 DOI: 10.1002/evl3.227] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 02/06/2021] [Accepted: 03/29/2021] [Indexed: 01/11/2023] Open
Abstract
Chromosomal inversions have long been recognized for their role in local adaptation. By suppressing recombination in heterozygous individuals, they can maintain coadapted gene complexes and protect them from homogenizing effects of gene flow. However, to fully understand their importance for local adaptation we need to know their influence on phenotypes under divergent selection. For this, the marine snail Littorina saxatilis provides an ideal study system. Divergent ecotypes adapted to wave action and crab predation occur in close proximity on intertidal shores with gene flow between them. Here, we used F2 individuals obtained from crosses between the ecotypes to test for associations between genomic regions and traits distinguishing the Crab‐/Wave‐adapted ecotypes including size, shape, shell thickness, and behavior. We show that most of these traits are influenced by two previously detected inversion regions that are divergent between ecotypes. We thus gain a better understanding of one important underlying mechanism responsible for the rapid and repeated formation of ecotypes: divergent selection acting on inversions. We also found that some inversions contributed to more than one trait suggesting that they may contain several loci involved in adaptation, consistent with the hypothesis that suppression of recombination within inversions facilitates differentiation in the presence of gene flow.
Collapse
Affiliation(s)
- Eva L Koch
- Department of Animal and Plant Sciences University of Sheffield Sheffield United Kingdom
| | - Hernán E Morales
- Evolutionary Genetics Section Globe Institute University of Copenhagen Copenhagen Denmark.,Department of Marine Sciences University of Gothenburg Strömstad 45296 Sweden
| | - Jenny Larsson
- Department of Animal and Plant Sciences University of Sheffield Sheffield United Kingdom
| | - Anja M Westram
- Department of Animal and Plant Sciences University of Sheffield Sheffield United Kingdom.,IST Austria Klosterneuburg Austria
| | - Rui Faria
- Department of Animal and Plant Sciences University of Sheffield Sheffield United Kingdom.,CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos Universidade do Porto Vairão Portugal
| | - Alan R Lemmon
- Department of Scientific Computing Florida State University Tallahassee Florida FL 32306-4120
| | - E Moriarty Lemmon
- Department of Biological Science Florida State University Tallahassee Florida FL 32306-4295
| | - Kerstin Johannesson
- Department of Marine Sciences University of Gothenburg Strömstad 45296 Sweden
| | - Roger K Butlin
- Department of Animal and Plant Sciences University of Sheffield Sheffield United Kingdom.,Department of Marine Sciences University of Gothenburg Strömstad 45296 Sweden
| |
Collapse
|
22
|
Colnaghi M, Lane N, Pomiankowski A. Genome expansion in early eukaryotes drove the transition from lateral gene transfer to meiotic sex. eLife 2020; 9:58873. [PMID: 32990598 PMCID: PMC7524546 DOI: 10.7554/elife.58873] [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: 05/13/2020] [Accepted: 09/03/2020] [Indexed: 12/17/2022] Open
Abstract
Prokaryotes acquire genes from the environment via lateral gene transfer (LGT). Recombination of environmental DNA can prevent the accumulation of deleterious mutations, but LGT was abandoned by the first eukaryotes in favour of sexual reproduction. Here we develop a theoretical model of a haploid population undergoing LGT which includes two new parameters, genome size and recombination length, neglected by previous theoretical models. The greater complexity of eukaryotes is linked with larger genomes and we demonstrate that the benefit of LGT declines rapidly with genome size. The degeneration of larger genomes can only be resisted by increases in recombination length, to the same order as genome size - as occurs in meiosis. Our results can explain the strong selective pressure towards the evolution of sexual cell fusion and reciprocal recombination during early eukaryotic evolution - the origin of meiotic sex.
Collapse
Affiliation(s)
- Marco Colnaghi
- CoMPLEX, University College London, London, United Kingdom.,Department of Genetics, Evolution and Environment University College London, London, United Kingdom
| | - Nick Lane
- CoMPLEX, University College London, London, United Kingdom.,Department of Genetics, Evolution and Environment University College London, London, United Kingdom
| | - Andrew Pomiankowski
- CoMPLEX, University College London, London, United Kingdom.,Department of Genetics, Evolution and Environment University College London, London, United Kingdom
| |
Collapse
|
23
|
From molecules to populations: appreciating and estimating recombination rate variation. Nat Rev Genet 2020; 21:476-492. [DOI: 10.1038/s41576-020-0240-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/15/2020] [Indexed: 02/07/2023]
|
24
|
Samuk K, Manzano-Winkler B, Ritz KR, Noor MAF. Natural Selection Shapes Variation in Genome-wide Recombination Rate in Drosophila pseudoobscura. Curr Biol 2020; 30:1517-1528.e6. [PMID: 32275873 DOI: 10.1016/j.cub.2020.03.053] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 12/16/2019] [Accepted: 03/20/2020] [Indexed: 12/30/2022]
Abstract
While recombination is widely recognized to be a key modulator of numerous evolutionary phenomena, we have a poor understanding of how recombination rate itself varies and evolves within a species. Here, we performed a comprehensive study of recombination rate (rate of meiotic crossing over) in two natural populations of Drosophila pseudoobscura from Utah and Arizona, USA. We used an amplicon sequencing approach to obtain high-quality genotypes in approximately 8,000 individual backcrossed offspring (17 mapping populations with roughly 530 individuals each), for which we then quantified crossovers. Interestingly, variation in recombination rate within and between populations largely manifested as differences in genome-wide recombination rate rather than remodeling of the local recombination landscape. Comparing populations, we discovered individuals from the Utah population displayed on average 8% higher crossover rates than the Arizona population, a statistically significant difference. Using a QST-FST analysis, we found that this difference in crossover rate was dramatically higher than expected under neutrality, indicating that this difference may have been driven by natural selection. Finally, using a combination of short- and long-read whole-genome sequencing, we found no significant association between crossover rate and structural variation at the 200-400 kb scale. Our results demonstrate that (1) there is abundant variation in genome-wide crossover rate in natural populations, (2) at the 200-400 kb scale, recombination rate appears to vary largely genome-wide, rather than in specific intervals, and (3) interpopulation differences in recombination rate may be the result of local adaptation.
Collapse
Affiliation(s)
- Kieran Samuk
- Department of Biology, Duke University, Durham, NC 27708, USA.
| | | | - Kathryn R Ritz
- Department of Biology, Duke University, Durham, NC 27708, USA
| | | |
Collapse
|
25
|
Otto SP. Evolutionary potential for genomic islands of sexual divergence on recombining sex chromosomes. THE NEW PHYTOLOGIST 2019; 224:1241-1251. [PMID: 31361905 DOI: 10.1111/nph.16083] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 07/22/2019] [Indexed: 06/10/2023]
Abstract
Differentiated sex chromosomes are thought to develop through the accumulation of polymorphisms at loci subject to opposing selection between males and females, and/or between haploids and diploids. As sex chromosomes differentiate, reduced recombination becomes favored between selected loci and the sex-determining region, strengthening genetic associations between alleles favored in a sex and the corresponding sex chromosome. Here a model is analyzed to explore whether polymorphism at one sexually or ploidally antagonistic locus facilitates the spread of rare alleles at other loci experiencing antagonistic selection, promoting further differentiation of the sex chromosomes. It is found that antagonistic polymorphisms can spread and capture other such loci, building 'genomic islands' of differentiation on sex chromosomes, but the conditions are very restrictive, requiring the loci to be strongly selected, tightly linked and distant from the sex-determining region. Epistatic interactions can facilitate the promotion of polymorphism among selected loci, but only if preferentially favoring heterozygotes. Although these results apply to any taxa, plants provide a fertile ground for testing these and related theories given the recurrent evolutionary transitions to dioecy, which provide multiple opportunities to track the early evolution of sex chromosomes.
Collapse
Affiliation(s)
- Sarah P Otto
- Department of Zoology & Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| |
Collapse
|
26
|
Hodgins KA, Yeaman S. Mating system impacts the genetic architecture of adaptation to heterogeneous environments. THE NEW PHYTOLOGIST 2019; 224:1201-1214. [PMID: 31505030 DOI: 10.1111/nph.16186] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 08/27/2019] [Indexed: 06/10/2023]
Abstract
Self-fertilisation has consequences for variation across the genome as it reduces effective population size, effect recombination rates and pollen flow, with implications for local adaptation. We conducted simulations of divergent stabilising selection on a quantitative trait with drift, pollen flow, mutation, recombination and different outcrossing rates. We quantified trait divergence and the genetic architecture of adaptation. We conducted an FST outlier analysis to identify candidate loci and quantified the impact of mating system on detectability. Selfing promoted trait divergence mainly through reductions in pollen flow. Moreover, trait architecture became more diffuse with selfing. Average effect size of trait loci was lower, while the number of loci, and their clustering distance increased. The genetic architecture of selfers was also more diffuse than outcrossers for equivalent migration rates. However, when deleterious alleles were included, architectures became more concentrated in selfers, likely to be because of reductions in population size caused by mutational meltdown and impacts of background selection on Ne . Our simulations demonstrate that mating system has important impacts on adaptive divergence of traits and the genetic landscape underlying that divergence. Selfing has a significant effect on detectability of regions of the genome important for adaptation because of neutral divergence and diffuse trait architecture.
Collapse
Affiliation(s)
- Kathryn A Hodgins
- School of Biological Sciences, Monash University - Clayton Campus, Building 17, Wellington Road, Clayton, Victoria, 3800, Australia
| | - Sam Yeaman
- Department of Biological Sciences, University of Calgary, 507 Campus Drive NW, Calgary, AB, T2N 4S8, Canada
| |
Collapse
|
27
|
Hämälä T, Savolainen O. Genomic Patterns of Local Adaptation under Gene Flow in Arabidopsis lyrata. Mol Biol Evol 2019; 36:2557-2571. [PMID: 31236594 DOI: 10.1093/molbev/msz149] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 05/02/2019] [Accepted: 06/17/2019] [Indexed: 12/12/2022] Open
Abstract
AbstractShort-scale local adaptation is a complex process involving selection, migration, and drift. The expected effects on the genome are well grounded in theory but examining these on an empirical level has proven difficult, as it requires information about local selection, demographic history, and recombination rate variation. Here, we use locally adapted and phenotypically differentiated Arabidopsis lyrata populations from two altitudinal gradients in Norway to test these expectations at the whole-genome level. Demography modeling indicates that populations within the gradients diverged <2 kya and that the sites are connected by gene flow. The gene flow estimates are, however, highly asymmetric with migration from high to low altitudes being several times more frequent than vice versa. To detect signatures of selection for local adaptation, we estimate patterns of lineage-specific differentiation among these populations. Theory predicts that gene flow leads to concentration of adaptive loci in areas of low recombination; a pattern we observe in both lowland-alpine comparisons. Although most selected loci display patterns of conditional neutrality, we found indications of genetic trade-offs, with one locus particularly showing high differentiation and signs of selection in both populations. Our results further suggest that resistance to solar radiation is an important adaptation to alpine environments, while vegetative growth and bacterial defense are indicated as selected traits in the lowland habitats. These results provide insights into genetic architectures and evolutionary processes driving local adaptation under gene flow. We also contribute to understanding of traits and biological processes underlying alpine adaptation in northern latitudes.
Collapse
Affiliation(s)
- Tuomas Hämälä
- Department of Ecology and Genetics, University of Oulu, Oulu, Finland
- Biocenter Oulu, University of Oulu, Oulu, Finland
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN
| | - Outi Savolainen
- Department of Ecology and Genetics, University of Oulu, Oulu, Finland
- Biocenter Oulu, University of Oulu, Oulu, Finland
| |
Collapse
|
28
|
Mérot C, Berdan EL, Babin C, Normandeau E, Wellenreuther M, Bernatchez L. Intercontinental karyotype-environment parallelism supports a role for a chromosomal inversion in local adaptation in a seaweed fly. Proc Biol Sci 2019; 285:rspb.2018.0519. [PMID: 29925615 PMCID: PMC6030540 DOI: 10.1098/rspb.2018.0519] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 05/24/2018] [Indexed: 12/20/2022] Open
Abstract
Large chromosomal rearrangements are thought to facilitate adaptation to heterogeneous environments by limiting genomic recombination. Indeed, inversions have been implicated in adaptation along environmental clines and in ecotype specialization. Here, we combine classical ecological studies and population genetics to investigate an inversion polymorphism previously documented in Europe among natural populations of the seaweed fly Coelopa frigida along a latitudinal cline in North America. We test if the inversion is present in North America and polymorphic, assess which environmental conditions modulate the inversion karyotype frequencies, and document the relationship between inversion karyotype and adult size. We sampled nearly 2000 flies from 20 populations along several environmental gradients to quantify associations of inversion frequencies to heterogeneous environmental variables. Genotyping and phenotyping showed a widespread and conserved inversion polymorphism between Europe and America. Variation in inversion frequency was significantly associated with environmental factors, with parallel patterns between continents, indicating that the inversion may play a role in local adaptation. The three karyotypes of the inversion are differently favoured across micro-habitats and represent life-history strategies likely to be maintained by the collective action of several mechanisms of balancing selection. Our study adds to the mounting evidence that inversions are facilitators of adaptation and enhance within-species diversity.
Collapse
Affiliation(s)
- Claire Mérot
- Département de biologie, Université Laval, Quebec, Canada
| | - Emma L Berdan
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Charles Babin
- Département de biologie, Université Laval, Quebec, Canada
| | | | - Maren Wellenreuther
- School of Biological Sciences, University of Auckland, New Zealand.,Seafood Research Unit, Port Nelson, Nelson, New Zealand
| | | |
Collapse
|
29
|
Pfeifer SP, Laurent S, Sousa VC, Linnen CR, Foll M, Excoffier L, Hoekstra HE, Jensen JD. The Evolutionary History of Nebraska Deer Mice: Local Adaptation in the Face of Strong Gene Flow. Mol Biol Evol 2019; 35:792-806. [PMID: 29346646 PMCID: PMC5905656 DOI: 10.1093/molbev/msy004] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The interplay of gene flow, genetic drift, and local selective pressure is a dynamic process that has been well studied from a theoretical perspective over the last century. Wright and Haldane laid the foundation for expectations under an island-continent model, demonstrating that an island-specific beneficial allele may be maintained locally if the selection coefficient is larger than the rate of migration of the ancestral allele from the continent. Subsequent extensions of this model have provided considerably more insight. Yet, connecting theoretical results with empirical data has proven challenging, owing to a lack of information on the relationship between genotype, phenotype, and fitness. Here, we examine the demographic and selective history of deer mice in and around the Nebraska Sand Hills, a system in which variation at the Agouti locus affects cryptic coloration that in turn affects the survival of mice in their local habitat. We first genotyped 250 individuals from 11 sites along a transect spanning the Sand Hills at 660,000 single nucleotide polymorphisms across the genome. Using these genomic data, we found that deer mice first colonized the Sand Hills following the last glacial period. Subsequent high rates of gene flow have served to homogenize the majority of the genome between populations on and off the Sand Hills, with the exception of the Agouti pigmentation locus. Furthermore, mutations at this locus are strongly associated with the pigment traits that are strongly correlated with local soil coloration and thus responsible for cryptic coloration.
Collapse
Affiliation(s)
- Susanne P Pfeifer
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,School of Life Sciences, Center for Evolution & Medicine, Arizona State University, Tempe, AZ
| | - Stefan Laurent
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Vitor C Sousa
- Institute of Ecology & Evolution, University of Berne, Berne, Switzerland.,Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | | | - Matthieu Foll
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Laurent Excoffier
- Institute of Ecology & Evolution, University of Berne, Berne, Switzerland
| | - Hopi E Hoekstra
- Department of Organismic & Evolutionary Biology and Molecular & Cellular Biology, Museum of Comparative Zoology, Howard Hughes Medical Institute, Harvard University, Cambridge, MA
| | - Jeffrey D Jensen
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,School of Life Sciences, Center for Evolution & Medicine, Arizona State University, Tempe, AZ
| |
Collapse
|
30
|
Lotterhos KE, Yeaman S, Degner J, Aitken S, Hodgins KA. Modularity of genes involved in local adaptation to climate despite physical linkage. Genome Biol 2018; 19:157. [PMID: 30290843 PMCID: PMC6173883 DOI: 10.1186/s13059-018-1545-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 09/18/2018] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Linkage among genes experiencing different selection pressures can make natural selection less efficient. Theory predicts that when local adaptation is driven by complex and non-covarying stresses, increased linkage is favored for alleles with similar pleiotropic effects, with increased recombination favored among alleles with contrasting pleiotropic effects. Here, we introduce a framework to test these predictions with a co-association network analysis, which clusters loci based on differing associations. We use this framework to study the genetic architecture of local adaptation to climate in lodgepole pine, Pinus contorta, based on associations with environments. RESULTS We identify many clusters of candidate genes and SNPs associated with distinct environments, including aspects of aridity and freezing, and discover low recombination rates among some candidate genes in different clusters. Only a few genes contain SNPs with effects on more than one distinct aspect of climate. There is limited correspondence between co-association networks and gene regulatory networks. We further show how associations with environmental principal components can lead to misinterpretation. Finally, simulations illustrate both benefits and caveats of co-association networks. CONCLUSIONS Our results support the prediction that different selection pressures favor the evolution of distinct groups of genes, each associating with a different aspect of climate. But our results went against the prediction that loci experiencing different sources of selection would have high recombination among them. These results give new insight into evolutionary debates about the extent of modularity, pleiotropy, and linkage in the evolution of genetic architectures.
Collapse
Affiliation(s)
- Katie E Lotterhos
- Department of Marine and Environmental Sciences, Northeastern Marine Science Center, 430 Nahant Rd, Nahant, MA, 01908, USA.
| | - Sam Yeaman
- Department of Biological Sciences, University of Calgary, Calgary, AB, T2N1N4, Canada
| | - Jon Degner
- Department of Forest and Conservation Sciences, Faculty of Forestry, Vancouver, BC, V6T 1Z4, Canada
| | - Sally Aitken
- Department of Forest and Conservation Sciences, Faculty of Forestry, Vancouver, BC, V6T 1Z4, Canada
| | - Kathryn A Hodgins
- School of Biological Sciences, Monash University, Wellington Rd, Clayton, Melbourne, VIC, 3800, Australia
| |
Collapse
|
31
|
Baduel P, Bray S, Vallejo-Marin M, Kolář F, Yant L. The “Polyploid Hop”: Shifting Challenges and Opportunities Over the Evolutionary Lifespan of Genome Duplications. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00117] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
32
|
Vanhoenacker E, Sandell L, Roze D. Stabilizing selection, mutational bias, and the evolution of sex*. Evolution 2018; 72:1740-1758. [DOI: 10.1111/evo.13547] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 06/20/2018] [Indexed: 12/16/2022]
Affiliation(s)
- Eloïse Vanhoenacker
- CNRS UMI 3614 Evolutionary Biology and Ecology of Algae 29688 Roscoff France
- Sorbonne Université 29688 Roscoff France
| | - Linnéa Sandell
- Department of Zoology University of British Columbia Vancouver BC V6T1Z4 Canada
| | - Denis Roze
- CNRS UMI 3614 Evolutionary Biology and Ecology of Algae 29688 Roscoff France
- Sorbonne Université 29688 Roscoff France
| |
Collapse
|
33
|
Lynch ZR, Penley MJ, Morran LT. Turnover in local parasite populations temporarily favors host outcrossing over self-fertilization during experimental evolution. Ecol Evol 2018; 8:6652-6662. [PMID: 30038764 PMCID: PMC6053587 DOI: 10.1002/ece3.4150] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 03/28/2018] [Accepted: 03/29/2018] [Indexed: 11/12/2022] Open
Abstract
The ubiquity of outcrossing in plants and animals is difficult to explain given its costs relative to self-fertilization. Despite these costs, exposure to changing environmental conditions can temporarily favor outcrossing over selfing. Therefore, recurring episodes of environmental change are predicted to favor the maintenance of outcrossing. Studies of host-parasite coevolution have provided strong support for this hypothesis. However, it is unclear whether multiple exposures to novel parasite genotypes in the absence of coevolution are sufficient to favor outcrossing. Using the nematode Caenorhabditis elegans and the bacterial parasite Serratia marcescens, we studied host responses to parasite turnover. We passaged several replicates of a host population that was well-adapted to the S. marcescens strain Sm2170 with either Sm2170 or one of three novel S. marcescens strains, each derived from Sm2170, for 18 generations. We found that hosts exposed to novel parasites maintained higher outcrossing rates than hosts exposed to Sm2170. Nonetheless, host outcrossing rates declined over time against all but the most virulent novel parasite strain. Hosts exposed to the most virulent novel strain exhibited increased outcrossing rates for approximately 12 generations, but did not maintain elevated levels of outcrossing throughout the experiment. Thus, parasite turnover can transiently increase host outcrossing. These results suggest that recurring episodes of parasite turnover have the potential to favor the maintenance of host outcrossing. However, such maintenance may require frequent exposure to novel virulent parasites, rapid rates of parasite turnover, and substantial host gene flow.
Collapse
|
34
|
Roesti M. Varied Genomic Responses to Maladaptive Gene Flow and Their Evidence. Genes (Basel) 2018; 9:E298. [PMID: 29899287 PMCID: PMC6027369 DOI: 10.3390/genes9060298] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/17/2018] [Accepted: 05/30/2018] [Indexed: 12/02/2022] Open
Abstract
Adaptation to a local environment often occurs in the face of maladaptive gene flow. In this perspective, I discuss several ideas on how a genome may respond to maladaptive gene flow during adaptation. On the one hand, selection can build clusters of locally adaptive alleles at fortuitously co-localized loci within a genome, thereby facilitating local adaptation with gene flow ('allele-only clustering'). On the other hand, the selective pressure to link adaptive alleles may drive co-localization of the actual loci relevant for local adaptation within a genome through structural genome changes or an evolving intra-genomic crossover rate ('locus clustering'). While the expected outcome is, in both cases, a higher frequency of locally adaptive alleles in some genome regions than others, the molecular units evolving in response to gene flow differ (i.e., alleles versus loci). I argue that, although making this distinction is important, we commonly lack the critical empirical evidence to do so. This is mainly because many current approaches are biased towards detecting local adaptation in genome regions with low crossover rates. The importance of low-crossover genome regions for adaptation with gene flow, such as in co-localizing relevant loci within a genome, thus remains unclear. Future empirical investigations should address these questions by making use of comparative genomics, where multiple de novo genome assemblies from species evolved under different degrees of genetic exchange are compared. This research promises to advance our understanding of how a genome adapts to maladaptive gene flow, thereby promoting adaptive divergence and reproductive isolation.
Collapse
Affiliation(s)
- Marius Roesti
- Biodiversity Research Centre and Zoology Department, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
| |
Collapse
|
35
|
Dapper AL, Payseur BA. Connecting theory and data to understand recombination rate evolution. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0469. [PMID: 29109228 DOI: 10.1098/rstb.2016.0469] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2017] [Indexed: 02/03/2023] Open
Abstract
Meiotic recombination is necessary for successful gametogenesis in most sexually reproducing organisms and is a fundamental genomic parameter, influencing the efficacy of selection and the fate of new mutations. The molecular and evolutionary functions of recombination should impose strong selective constraints on the range of recombination rates. Yet, variation in recombination rate is observed on a variety of genomic and evolutionary scales. In the past decade, empirical studies have described variation in recombination rate within genomes, between individuals, between sexes, between populations and between species. At the same time, theoretical work has provided an increasingly detailed picture of the evolutionary advantages to recombination. Perhaps surprisingly, the causes of natural variation in recombination rate remain poorly understood. We argue that empirical and theoretical approaches to understand the evolution of recombination have proceeded largely independently of each other. Most models that address the evolution of recombination rate were created to explain the evolutionary advantage of recombination rather than quantitative differences in rate among individuals. Conversely, most empirical studies aim to describe variation in recombination rate, rather than to test evolutionary hypotheses. In this Perspective, we argue that efforts to integrate the rich bodies of empirical and theoretical work on recombination rate are crucial to moving this field forward. We provide new directions for the development of theory and the production of data that will jointly close this gap.This article is part of the themed issue 'Evolutionary causes and consequences of recombination rate variation in sexual organisms'.
Collapse
Affiliation(s)
- Amy L Dapper
- Laboratory of Genetics, University of Wisconsin, Madison, WI 53706, USA
| | - Bret A Payseur
- Laboratory of Genetics, University of Wisconsin, Madison, WI 53706, USA
| |
Collapse
|
36
|
Stapley J, Feulner PGD, Johnston SE, Santure AW, Smadja CM. Variation in recombination frequency and distribution across eukaryotes: patterns and processes. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0455. [PMID: 29109219 PMCID: PMC5698618 DOI: 10.1098/rstb.2016.0455] [Citation(s) in RCA: 212] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2017] [Indexed: 01/04/2023] Open
Abstract
Recombination, the exchange of DNA between maternal and paternal chromosomes during meiosis, is an essential feature of sexual reproduction in nearly all multicellular organisms. While the role of recombination in the evolution of sex has received theoretical and empirical attention, less is known about how recombination rate itself evolves and what influence this has on evolutionary processes within sexually reproducing organisms. Here, we explore the patterns of, and processes governing recombination in eukaryotes. We summarize patterns of variation, integrating current knowledge with an analysis of linkage map data in 353 organisms. We then discuss proximate and ultimate processes governing recombination rate variation and consider how these influence evolutionary processes. Genome-wide recombination rates (cM/Mb) can vary more than tenfold across eukaryotes, and there is large variation in the distribution of recombination events across closely related taxa, populations and individuals. We discuss how variation in rate and distribution relates to genome architecture, genetic and epigenetic mechanisms, sex, environmental perturbations and variable selective pressures. There has been great progress in determining the molecular mechanisms governing recombination, and with the continued development of new modelling and empirical approaches, there is now also great opportunity to further our understanding of how and why recombination rate varies.This article is part of the themed issue 'Evolutionary causes and consequences of recombination rate variation in sexual organisms'.
Collapse
Affiliation(s)
- Jessica Stapley
- Centre for Adaptation to a Changing Environment, IBZ, ETH Zürich, 8092 Zürich, Switzerland
| | - Philine G D Feulner
- Department of Fish Ecology and Evolution, Centre of Ecology, Evolution and Biogeochemistry, EAWAG Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland.,Division of Aquatic Ecology and Evolution, Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
| | - Susan E Johnston
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3JY, UK
| | - Anna W Santure
- School of Biological Sciences, University of Auckland, Auckland 1142, New Zealand
| | - Carole M Smadja
- Institut des Sciences de l'Evolution UMR 5554, CNRS, IRD, EPHE, Université de Montpellier, 3095 Montpellier cedex 05, France
| |
Collapse
|
37
|
Reeve J, Ortiz-Barrientos D, Engelstädter J. The evolution of recombination rates in finite populations during ecological speciation. Proc Biol Sci 2017; 283:rspb.2016.1243. [PMID: 27798297 DOI: 10.1098/rspb.2016.1243] [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] [Received: 06/05/2016] [Accepted: 10/04/2016] [Indexed: 11/12/2022] Open
Abstract
Recombination can impede ecological speciation with gene flow by mixing locally adapted genotypes with maladapted migrant genotypes from a divergent population. In such a scenario, suppression of recombination can be selectively favoured. However, in finite populations evolving under the influence of random genetic drift, recombination can also facilitate adaptation by reducing Hill-Robertson interference between loci under selection. In this case, increased recombination rates can be favoured. Although these two major effects on recombination have been studied individually, their joint effect on ecological speciation with gene flow remains unexplored. Using a mathematical model, we investigated the evolution of recombination rates in two finite populations that exchange migrants while adapting to contrasting environments. Our results indicate a two-step dynamic where increased recombination is first favoured (in response to the Hill-Robertson effect), and then disfavoured, as the cost of recombining locally with maladapted migrant genotypes increases over time (the maladaptive gene flow effect). In larger populations, a stronger initial benefit for recombination was observed, whereas high migration rates intensify the long-term cost of recombination. These dynamics may have important implications for our understanding of the conditions that facilitate incipient speciation with gene flow and the evolution of recombination in finite populations.
Collapse
Affiliation(s)
- James Reeve
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Daniel Ortiz-Barrientos
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jan Engelstädter
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| |
Collapse
|
38
|
Ortiz‐Barrientos D, James ME. Evolution of recombination rates and the genomic landscape of speciation. J Evol Biol 2017; 30:1519-1521. [DOI: 10.1111/jeb.13116] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 05/07/2017] [Accepted: 05/08/2017] [Indexed: 01/02/2023]
Affiliation(s)
- D. Ortiz‐Barrientos
- School of Biological Sciences The University of Queensland St Lucia Qld Australia
| | - M. E. James
- School of Biological Sciences The University of Queensland St Lucia Qld Australia
| |
Collapse
|
39
|
Matsumoto T, Yoshida K, Kitano J. Contribution of gene flow to the evolution of recombination suppression in sex chromosomes. J Theor Biol 2017; 431:25-31. [PMID: 28782550 DOI: 10.1016/j.jtbi.2017.08.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 06/20/2017] [Accepted: 08/02/2017] [Indexed: 10/19/2022]
Abstract
Polymorphism of alleles that benefit one sex but harm the other (sexually antagonistic alleles) generates selective pressures for reduced recombination between themselves and sex-determination loci. Such polymorphism can be maintained within a population when selection coefficients are sufficiently balanced between males and females. However, if regulatory mutations restrict gene expression only to one sex, these alleles become neutral in the other sex and easily fixed within a population, removing the selective pressures for recombination suppression in sex chromosomes. When there is spatial variation in selection regimes, however, alleles that are deleterious in one sex and neutral in the other can be maintained in other neighboring populations and gene flow may continuously supply deleterious alleles. We hypothesized that this maintenance of genetic variation may promote the establishment of recombination suppression in sex chromosomes even in cases where selection is limited to one sex. Using individual-based simulations, we show that spatial variation in male-limited selection and gene flow can promote the establishment of Y-autosome fusions, a special case of recombination suppression in sex chromosomes. This can be explained by the fact that fused Y-chromosomes that capture alleles that are beneficial for local males have a higher mean fitness compared to unfused Y chromosomes in the presence of deleterious gene flow. We also simulated the case of sex-concordant selection and found that gene flow of alleles that are deleterious in both sexes did not substantially increase the establishment rates of Y-autosome fusions across the parameter space examined. This can be accounted for by the fact that foreign alleles that are deleterious in both sexes can be efficiently removed from the population compared to alleles that are neutral in females. These results indicate that how gene flow affects the establishment rates of Y-autosome fusions depends largely on selection regimes. Spatial variation in sex-specific selection and gene flow should be appreciated as a factor affecting sex chromosome evolution.
Collapse
Affiliation(s)
- Tomotaka Matsumoto
- Division of Evolutionary Genetics, National Institute of Genetics, Yata 1111, Mishima, Shizuoka 411-8540, Japan
| | - Kohta Yoshida
- Division of Ecological Genetics, National Institute of Genetics, Yata 1111, Mishima, Shizuoka 411-8540, Japan
| | - Jun Kitano
- Division of Ecological Genetics, National Institute of Genetics, Yata 1111, Mishima, Shizuoka 411-8540, Japan.
| |
Collapse
|
40
|
Llaurens V, Whibley A, Joron M. Genetic architecture and balancing selection: the life and death of differentiated variants. Mol Ecol 2017; 26:2430-2448. [PMID: 28173627 DOI: 10.1111/mec.14051] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 12/15/2016] [Accepted: 12/19/2016] [Indexed: 01/02/2023]
Abstract
Balancing selection describes any form of natural selection, which results in the persistence of multiple variants of a trait at intermediate frequencies within populations. By offering up a snapshot of multiple co-occurring functional variants and their interactions, systems under balancing selection can reveal the evolutionary mechanisms favouring the emergence and persistence of adaptive variation in natural populations. We here focus on the mechanisms by which several functional variants for a given trait can arise, a process typically requiring multiple epistatic mutations. We highlight how balancing selection can favour specific features in the genetic architecture and review the evolutionary and molecular mechanisms shaping this architecture. First, balancing selection affects the number of loci underlying differentiated traits and their respective effects. Control by one or few loci favours the persistence of differentiated functional variants by limiting intergenic recombination, or its impact, and may sometimes lead to the evolution of supergenes. Chromosomal rearrangements, particularly inversions, preventing adaptive combinations from being dissociated are increasingly being noted as features of such systems. Similarly, due to the frequency of heterozygotes maintained by balancing selection, dominance may be a key property of adaptive variants. High heterozygosity and limited recombination also influence associated genetic load, as linked recessive deleterious mutations may be sheltered. The capture of deleterious elements in a locus under balancing selection may reinforce polymorphism by further promoting heterozygotes. Finally, according to recent genomewide scans, balanced polymorphism might be more pervasive than generally thought. We stress the need for both functional and ecological studies to characterize the evolutionary mechanisms operating in these systems.
Collapse
Affiliation(s)
- Violaine Llaurens
- Institut de Systématique Evolution et Biodiversité (UMR 7205 CNRS, MNHN, UPMC, EPHE), Muséum National d'Histoire Naturelle - CP50, 45 rue Buffon, 75005, Paris, France
| | - Annabel Whibley
- Cell and Developmental Biology, John Innes Centre, Norwich, Norfolk, NR4 7UH, UK
| | - Mathieu Joron
- Centre d'Ecologie Fonctionnelle et Evolutive (UMR 5175 CNRS, Université de Montpellier, Université Paul Valéry Montpellier, EPHE), 1919 route de Mende, 34293, Montpellier, France
| |
Collapse
|
41
|
Lavanchy G, Strehler M, Llanos Roman MN, Lessard-Therrien M, Humbert JY, Dumas Z, Jalvingh K, Ghali K, Fontcuberta García-Cuenca A, Zijlstra B, Arlettaz R, Schwander T. Habitat heterogeneity favors asexual reproduction in natural populations of grassthrips. Evolution 2016; 70:1780-90. [PMID: 27346066 PMCID: PMC5129508 DOI: 10.1111/evo.12990] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 05/23/2016] [Accepted: 06/05/2016] [Indexed: 01/23/2023]
Abstract
Explaining the overwhelming success of sex among eukaryotes is difficult given the obvious costs of sex relative to asexuality. Different studies have shown that sex can provide benefits in spatially heterogeneous environments under specific conditions, but whether spatial heterogeneity commonly contributes to the maintenance of sex in natural populations remains unknown. We experimentally manipulated habitat heterogeneity for sexual and asexual thrips lineages in natural populations and under seminatural mesocosm conditions by varying the number of hostplants available to these herbivorous insects. Asexual lineages rapidly replaced the sexual ones, independently of the level of habitat heterogeneity in mesocosms. In natural populations, the success of sexual thrips decreased with increasing habitat heterogeneity, with sexual thrips apparently only persisting in certain types of hostplant communities. Our results illustrate how genetic diversity-based mechanisms can favor asexuality instead of sex when sexual lineages co-occur with genetically variable asexual lineages.
Collapse
Affiliation(s)
- Guillaume Lavanchy
- Department of Ecology and Evolution, University of Lausanne, Biophore, Lausanne, Switzerland.
| | - Marie Strehler
- Department of Ecology and Evolution, University of Lausanne, Biophore, Lausanne, Switzerland
| | - Maria Noemi Llanos Roman
- Graduate School-Doctoral program in Biomedical Sciences, National University of Trujillo, Trujillo, Peru
| | - Malie Lessard-Therrien
- Institute of Ecology and Evolution, University of Bern, Baltzerstrasse, Bern, Switzerland
| | - Jean-Yves Humbert
- Institute of Ecology and Evolution, University of Bern, Baltzerstrasse, Bern, Switzerland
| | - Zoé Dumas
- Department of Ecology and Evolution, University of Lausanne, Biophore, Lausanne, Switzerland
| | - Kirsten Jalvingh
- Department of Ecology and Evolution, University of Lausanne, Biophore, Lausanne, Switzerland
| | - Karim Ghali
- Department of Ecology and Evolution, University of Lausanne, Biophore, Lausanne, Switzerland
| | | | - Bart Zijlstra
- Department of Ecology and Evolution, University of Lausanne, Biophore, Lausanne, Switzerland
| | - Raphaël Arlettaz
- Institute of Ecology and Evolution, University of Bern, Baltzerstrasse, Bern, Switzerland
| | - Tanja Schwander
- Department of Ecology and Evolution, University of Lausanne, Biophore, Lausanne, Switzerland
| |
Collapse
|
42
|
Sharp NP, Otto SP. Evolution of sex: Using experimental genomics to select among competing theories. Bioessays 2016; 38:751-7. [DOI: 10.1002/bies.201600074] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Sarah P. Otto
- Department of Zoology; University of British Columbia; Vancouver Canada
| |
Collapse
|
43
|
Yeaman S, Aeschbacher S, Bürger R. The evolution of genomic islands by increased establishment probability of linked alleles. Mol Ecol 2016; 25:2542-58. [DOI: 10.1111/mec.13611] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Revised: 02/24/2016] [Accepted: 02/29/2016] [Indexed: 01/16/2023]
Affiliation(s)
- Sam Yeaman
- Biological Sciences; University of Calgary; Calgary AB T2N 1N4 Canada
- Biodiversity Research Centre; University of British Columbia; Vancouver BC V6T 1Z4 Canada
| | - Simon Aeschbacher
- Department of Evolution and Ecology; University of California; Davis CA 95616 USA
| | - Reinhard Bürger
- Faculty of Mathematics; University of Vienna; Oskar-Morgenstern-Platz 1 A-1090 Vienna Austria
| |
Collapse
|
44
|
Tigano A, Friesen VL. Genomics of local adaptation with gene flow. Mol Ecol 2016; 25:2144-64. [DOI: 10.1111/mec.13606] [Citation(s) in RCA: 241] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/22/2016] [Accepted: 03/01/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Anna Tigano
- Department of Biology; Queen's University; Kingston ON K7L 3N6 Canada
| | - Vicki L. Friesen
- Department of Biology; Queen's University; Kingston ON K7L 3N6 Canada
| |
Collapse
|
45
|
Ortiz-Barrientos D, Engelstädter J, Rieseberg LH. Recombination Rate Evolution and the Origin of Species. Trends Ecol Evol 2016; 31:226-236. [PMID: 26831635 DOI: 10.1016/j.tree.2015.12.016] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/14/2015] [Accepted: 12/22/2015] [Indexed: 12/13/2022]
Abstract
A recipe for dissolving incipient species into a continuum of phenotypes is to recombine their genetic material. Therefore, students of speciation have become increasingly interested in the mechanisms by which recombination between locally adapted lineages is reduced. Evidence abounds that chromosomal rearrangements, via their suppression of recombination during meiosis in hybrids, play a major role in adaptation and speciation. By contrast, genic modifiers of recombination rates have been largely ignored in studies of speciation. We show how both types of reduction in recombination rates facilitate divergence in the face of gene flow, including the early stages of adaptive divergence, the persistence of species after secondary contact, and reinforcement.
Collapse
Affiliation(s)
- Daniel Ortiz-Barrientos
- The University of Queensland, School of Biological Sciences, St. Lucia, Queensland, Australia.
| | - Jan Engelstädter
- The University of Queensland, School of Biological Sciences, St. Lucia, Queensland, Australia
| | - Loren H Rieseberg
- University of British Columbia, Department of Botany, Vancouver, British Columbia, Canada; Indiana University, Biology Department, Bloomington, IN 47405-7005, USA
| |
Collapse
|
46
|
Aggarwal DD, Rashkovetsky E, Michalak P, Cohen I, Ronin Y, Zhou D, Haddad GG, Korol AB. Experimental evolution of recombination and crossover interference in Drosophila caused by directional selection for stress-related traits. BMC Biol 2015; 13:101. [PMID: 26614097 PMCID: PMC4661966 DOI: 10.1186/s12915-015-0206-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Accepted: 10/27/2015] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Population genetics predicts that tight linkage between new and/or pre-existing beneficial and deleterious alleles should decrease the efficiency of natural selection in finite populations. By decoupling beneficial and deleterious alleles and facilitating the combination of beneficial alleles, recombination accelerates the formation of high-fitness genotypes. This may impose indirect selection for increased recombination. Despite the progress in theoretical understanding, interplay between recombination and selection remains a controversial issue in evolutionary biology. Even less satisfactory is the situation with crossover interference, which is a deviation of double-crossover frequency in a pair of adjacent intervals from the product of recombination rates in the two intervals expected on the assumption of crossover independence. Here, we report substantial changes in recombination and interference in three long-term directional selection experiments with Drosophila melanogaster: for desiccation (~50 generations), hypoxia, and hyperoxia tolerance (>200 generations each). RESULTS For all three experiments, we found a high interval-specific increase of recombination frequencies in selection lines (up to 40-50% per interval) compared to the control lines. We also discovered a profound effect of selection on interference as expressed by an increased frequency of double crossovers in selection lines. Our results show that changes in interference are not necessarily coupled with increased recombination. CONCLUSIONS Our results support the theoretical predictions that adaptation to a new environment can promote evolution toward higher recombination. Moreover, this is the first evidence of selection for different recombination-unrelated traits potentially leading, not only to evolution toward increased crossover rates, but also to changes in crossover interference, one of the fundamental features of recombination.
Collapse
Affiliation(s)
| | | | - Pawel Michalak
- Virginia Bioinformatics Institute, Virginia Tech, Washington Street, MC 0477, Blacksburg, VA, 24061-0477, USA
| | - Irit Cohen
- Institute of Evolution, University of Haifa, Haifa, 3498838, Israel
| | - Yefim Ronin
- Institute of Evolution, University of Haifa, Haifa, 3498838, Israel
| | - Dan Zhou
- University of California, San Diego, USA
| | - Gabriel G Haddad
- University of California, San Diego, USA
- Rady Children's Hospital, San Diego, USA
| | - Abraham B Korol
- Institute of Evolution, University of Haifa, Haifa, 3498838, Israel.
| |
Collapse
|
47
|
Smukowski Heil CS, Ellison C, Dubin M, Noor MAF. Recombining without Hotspots: A Comprehensive Evolutionary Portrait of Recombination in Two Closely Related Species of Drosophila. Genome Biol Evol 2015; 7:2829-42. [PMID: 26430062 PMCID: PMC4684701 DOI: 10.1093/gbe/evv182] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2015] [Indexed: 12/12/2022] Open
Abstract
Meiotic recombination rate varies across the genome within and between individuals, populations, and species in virtually all taxa studied. In almost every species, this variation takes the form of discrete recombination hotspots, determined in some mammals by a protein called PRDM9. Hotspots and their determinants have a profound effect on the genomic landscape, and share certain features that extend across the tree of life. Drosophila, in contrast, are anomalous in their absence of hotspots, PRDM9, and other species-specific differences in the determination of recombination. To better understand the evolution of meiosis and general patterns of recombination across diverse taxa, we present a truly comprehensive portrait of recombination across time, combining recently published cross-based contemporary recombination estimates from each of two sister species with newly obtained linkage-disequilibrium-based historic estimates of recombination from both of these species. Using Drosophila pseudoobscura and Drosophila miranda as a model system, we compare recombination rate between species at multiple scales, and we suggest that Drosophila replicate the pattern seen in human-chimpanzee in which recombination rate is conserved at broad scales. We also find evidence of a species-wide recombination modifier(s), resulting in both a present and historic genome-wide elevation of recombination rates in D. miranda, and identify broad scale effects on recombination from the presence of an inversion. Finally, we reveal an unprecedented view of the distribution of recombination in D. pseudoobscura, illustrating patterns of linked selection and where recombination is taking place. Overall, by combining these estimation approaches, we highlight key similarities and differences in recombination between Drosophila and other organisms.
Collapse
Affiliation(s)
- Caiti S Smukowski Heil
- Biology Department, Duke University Genome Sciences Department, University of Washington
| | - Chris Ellison
- Department of Integrative Biology, University of California, Berkeley
| | | | | |
Collapse
|
48
|
Abstract
PURPOSE OF REVIEW An improved understanding of how recombination affects the evolutionary history of HIV is crucial to understand its current and future evolution. The present review aims to disentangle the manifold effects of recombination on HIV by discussing its effects on the evolutionary history and the adaptive potential of HIV in the context of concepts from evolutionary genetics and genomics. RECENT FINDINGS The increasing occurrence of secondary contacts between divergent subtype populations (during coinfection) results in increased observations of recombinants worldwide. Recombination is heterogeneous along the HIV genome. Consequences of recombination of HIV evolution are, in combination with other demographic processes, expected to either homogenize the genetic composition of HIV populations (homogenization) or provide the potential for novel adaptations (diversification). New methods in population genomics allow deep characterization of recombinant genome (the segment composition and origin) and their evolutionary trajectories. SUMMARY HIV recombinants increase worldwide and invade geographical regions where pure subtypes were previously predominant. This trend is expected to continue in the future, as ease to travel worldwide increases opportunities for recombination between divergent HIV strains. While the effects of recombination in HIV are much researched, more effort is required to characterize current HIV recombinant composition and dynamics. This can be achieved with new population genetic and genomic methods.
Collapse
|
49
|
Veen T, Otto SP. Liking the good guys: amplifying local adaptation via the evolution of condition‐dependent mate choice. J Evol Biol 2015; 28:1804-15. [DOI: 10.1111/jeb.12696] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 06/28/2015] [Accepted: 07/13/2015] [Indexed: 11/28/2022]
Affiliation(s)
- T. Veen
- Biodiversity Research Centre University of British Columbia Vancouver BC Canada
- Department of Integrative Biology University of Texas at Austin Austin TX USA
| | - S. P. Otto
- Department of Zoology University of British Columbia Vancouver BC Canada
| |
Collapse
|
50
|
Kleiman M, Hadany L. The evolution of obligate sex: the roles of sexual selection and recombination. Ecol Evol 2015; 5:2572-83. [PMID: 26257871 PMCID: PMC4523354 DOI: 10.1002/ece3.1516] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/20/2015] [Accepted: 04/23/2015] [Indexed: 11/20/2022] Open
Abstract
The evolution of sex is one of the greatest mysteries in evolutionary biology. An even greater mystery is the evolution of obligate sex, particularly when competing with facultative sex and not with complete asexuality. Here, we develop a stochastic simulation of an obligate allele invading a facultative population, where males are subject to sexual selection. We identify a range of parameters where sexual selection can contribute to the evolution of obligate sex: Especially when the cost of sex is low, mutation rate is high, and the facultative individuals do not reproduce sexually very often. The advantage of obligate sex becomes larger in the absence of recombination. Surprisingly, obligate sex can take over even when the population has a lower mean fitness as a result. We show that this is due to the high success of obligate males that can compensate the cost of sex.
Collapse
Affiliation(s)
- Maya Kleiman
- Department of Chemistry, Ben-Gurion University of the Negev Be'er-Sheva, 8410501, Israel
| | - Lilach Hadany
- Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, Tel Aviv University Ramat Aviv, 69978, Israel
| |
Collapse
|