1
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Dodge TO, Kim BY, Baczenas JJ, Banerjee SM, Gunn TR, Donny AE, Given LA, Rice AR, Haase Cox SK, Weinstein ML, Cross R, Moran BM, Haber K, Haghani NB, Machin Kairuz JA, Gellert HR, Du K, Aguillon SM, Tudor MS, Gutiérrez-Rodríguez C, Rios-Cardenas O, Morris MR, Schartl M, Powell DL, Schumer M. Structural genomic variation and behavioral interactions underpin a balanced sexual mimicry polymorphism. Curr Biol 2024:S0960-9822(24)01168-0. [PMID: 39326413 DOI: 10.1016/j.cub.2024.08.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 07/15/2024] [Accepted: 08/29/2024] [Indexed: 09/28/2024]
Abstract
How phenotypic diversity originates and persists within populations are classic puzzles in evolutionary biology. While balanced polymorphisms segregate within many species, it remains rare for both the genetic basis and the selective forces to be known, leading to an incomplete understanding of many classes of traits under balancing selection. Here, we uncover the genetic architecture of a balanced sexual mimicry polymorphism and identify behavioral mechanisms that may be involved in its maintenance in the swordtail fish Xiphophorus birchmanni. We find that ∼40% of X. birchmanni males develop a "false gravid spot," a melanic pigmentation pattern that mimics the "pregnancy spot" associated with sexual maturity in female live-bearing fish. Using genome-wide association mapping, we detect a single intergenic region associated with variation in the false gravid spot phenotype, which is upstream of kitlga, a melanophore patterning gene. By performing long-read sequencing within and across populations, we identify complex structural rearrangements between alternate alleles at this locus. The false gravid spot haplotype drives increased allele-specific expression of kitlga, which provides a mechanistic explanation for the increased melanophore abundance that causes the spot. By studying social interactions in the laboratory and in nature, we find that males with the false gravid spot experience less aggression; however, they also receive increased attention from other males and are disdained by females. These behavioral interactions may contribute to the maintenance of this phenotypic polymorphism in natural populations. We speculate that structural variants affecting gene regulation may be an underappreciated driver of balanced polymorphisms across diverse species.
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Affiliation(s)
- Tristram O Dodge
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA; Centro de Investigaciones Científicas de las Huastecas "Aguazarca" A.C., 16 de Septiembre, 392 Barrio Aguazarca, Calnali, Hidalgo 43240, México.
| | - Bernard Y Kim
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA
| | - John J Baczenas
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA
| | - Shreya M Banerjee
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA; Centro de Investigaciones Científicas de las Huastecas "Aguazarca" A.C., 16 de Septiembre, 392 Barrio Aguazarca, Calnali, Hidalgo 43240, México; Center for Population Biology and Department of Evolution and Ecology, University of California, Davis, 475 Storer Mall, Davis, CA 95616, USA
| | - Theresa R Gunn
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA; Centro de Investigaciones Científicas de las Huastecas "Aguazarca" A.C., 16 de Septiembre, 392 Barrio Aguazarca, Calnali, Hidalgo 43240, México
| | - Alex E Donny
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA; Centro de Investigaciones Científicas de las Huastecas "Aguazarca" A.C., 16 de Septiembre, 392 Barrio Aguazarca, Calnali, Hidalgo 43240, México
| | - Lyle A Given
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA
| | - Andreas R Rice
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA
| | - Sophia K Haase Cox
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA
| | - M Luke Weinstein
- Department of Biological Sciences, Ohio University, 7 Depot St., Athens, OH 45701, USA
| | - Ryan Cross
- Department of Biological Sciences, Ohio University, 7 Depot St., Athens, OH 45701, USA
| | - Benjamin M Moran
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA; Centro de Investigaciones Científicas de las Huastecas "Aguazarca" A.C., 16 de Septiembre, 392 Barrio Aguazarca, Calnali, Hidalgo 43240, México
| | - Kate Haber
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA; Berkeley High School, 1980 Allston Way, Berkeley, CA 94704, USA
| | - Nadia B Haghani
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA; Centro de Investigaciones Científicas de las Huastecas "Aguazarca" A.C., 16 de Septiembre, 392 Barrio Aguazarca, Calnali, Hidalgo 43240, México
| | | | - Hannah R Gellert
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA
| | - Kang Du
- Xiphophorus Genetic Stock Center, Texas State University, San Marcos, 601 University Drive, San Marcos, TX 78666, USA
| | - Stepfanie M Aguillon
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA; Centro de Investigaciones Científicas de las Huastecas "Aguazarca" A.C., 16 de Septiembre, 392 Barrio Aguazarca, Calnali, Hidalgo 43240, México; Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 612 Charles E. Young Drive South, Los Angeles, CA 90095, USA
| | - M Scarlett Tudor
- Cooperative Extension and Aquaculture Research Institute, University of Maine, 33 Salmon Farm Road, Franklin, ME 04634, USA
| | - Carla Gutiérrez-Rodríguez
- Red de Biología Evolutiva, Instituto de Ecología, A.C., Carretera antigua a Coatepec 351, Col. El Haya, Xalapa, Veracruz 91073, México
| | - Oscar Rios-Cardenas
- Red de Biología Evolutiva, Instituto de Ecología, A.C., Carretera antigua a Coatepec 351, Col. El Haya, Xalapa, Veracruz 91073, México
| | - Molly R Morris
- Department of Biological Sciences, Ohio University, 7 Depot St., Athens, OH 45701, USA
| | - Manfred Schartl
- Xiphophorus Genetic Stock Center, Texas State University, San Marcos, 601 University Drive, San Marcos, TX 78666, USA; Developmental Biochemistry, Biocenter, University of Würzburg, Am Hubland, 97074 Wuerzburg, Germany
| | - Daniel L Powell
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA; Centro de Investigaciones Científicas de las Huastecas "Aguazarca" A.C., 16 de Septiembre, 392 Barrio Aguazarca, Calnali, Hidalgo 43240, México; Department of Biology, Louisiana State University, 202 Life Science Building, Baton Rouge, LA 70803, USA
| | - Molly Schumer
- Department of Biology, Stanford University, 327 Campus Drive, Stanford, CA 94305, USA; Centro de Investigaciones Científicas de las Huastecas "Aguazarca" A.C., 16 de Septiembre, 392 Barrio Aguazarca, Calnali, Hidalgo 43240, México; Howard Hughes Medical Institute, 327 Campus Drive, Stanford, CA 94305, USA.
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2
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Zhang J, Schneller NM, Field MA, Chan CX, Miller DJ, Strugnell JM, Riginos C, Bay L, Cooke I. Chromosomal inversions harbour excess mutational load in the coral, Acropora kenti, on the Great Barrier Reef. Mol Ecol 2024; 33:e17468. [PMID: 39046252 DOI: 10.1111/mec.17468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 06/28/2024] [Accepted: 07/03/2024] [Indexed: 07/25/2024]
Abstract
The future survival of coral reefs in the Anthropocene depends on the capacity of corals to adapt as oceans warm and extreme weather events become more frequent. Targeted interventions designed to assist evolutionary processes in corals require a comprehensive understanding of the distribution and structure of standing variation, however, efforts to map genomic variation in corals have so far focussed almost exclusively on SNPs, overlooking structural variants that have been shown to drive adaptive processes in other taxa. Here, we show that the reef-building coral, Acropora kenti, harbours at least five large, highly polymorphic structural variants, all of which exhibit signatures of strongly suppressed recombination in heterokaryotypes, a feature commonly associated with chromosomal inversions. Based on their high minor allele frequency, uniform distribution across habitats and elevated genetic load, we propose that these inversions in A. kenti are likely to be under balancing selection. An excess of SNPs with high impact on protein-coding genes within these loci elevates their importance both as potential targets for adaptive selection and as contributors to genetic decline if coral populations become fragmented or inbred in future.
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Affiliation(s)
- Jia Zhang
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia
- Centre for Tropical Bioinformatics and Molecular Biology, James Cook University, Townsville, Queensland, Australia
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Nadja M Schneller
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia
- Centre for Tropical Bioinformatics and Molecular Biology, James Cook University, Townsville, Queensland, Australia
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Matt A Field
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia
- Centre for Tropical Bioinformatics and Molecular Biology, James Cook University, Townsville, Queensland, Australia
- Immunogenomics Lab, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Cheong Xin Chan
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - David J Miller
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia
- Centre for Tropical Bioinformatics and Molecular Biology, James Cook University, Townsville, Queensland, Australia
| | - Jan M Strugnell
- Centre for Tropical Bioinformatics and Molecular Biology, James Cook University, Townsville, Queensland, Australia
- Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville, Queensland, Australia
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Cynthia Riginos
- School of the Environment, The University of Queensland, Brisbane, Queensland, Australia
- Australian Institute of Marine Science, Townsville, Queensland, Australia
| | - Line Bay
- Australian Institute of Marine Science, Townsville, Queensland, Australia
| | - Ira Cooke
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia
- Centre for Tropical Bioinformatics and Molecular Biology, James Cook University, Townsville, Queensland, Australia
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3
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McAllester CS, Pool JE. Inversions Can Accumulate Balanced Sexual Antagonism: Evidence from Simulations and Drosophila Experiments. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.02.560529. [PMID: 37873205 PMCID: PMC10592935 DOI: 10.1101/2023.10.02.560529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Chromosomal inversion polymorphisms can be common, but the causes of their persistence are often unclear. We propose a model for the maintenance of inversion polymorphism, which requires that some variants contribute antagonistically to two phenotypes, one of which has negative frequency-dependent fitness. These conditions yield a form of frequency-dependent disruptive selection, favoring two predominant haplotypes segregating alleles that favor opposing antagonistic phenotypes. An inversion associated with one haplotype can reduce the fitness load incurred by generating recombinant offspring, reinforcing its linkage to the haplotype and enabling both haplotypes to accumulate more antagonistic variants than expected otherwise. We develop and apply a forward simulator to examine these dynamics under a tradeoff between survival and male display. These simulations indeed generate inversion-associated haplotypes with opposing sex-specific fitness effects. Antagonism strengthens with time, and can ultimately yield karyotypes at surprisingly predictable frequencies, with striking genotype frequency differences between sexes and between developmental stages. To test whether this model may contribute to well-studied yet enigmatic inversion polymorphisms in Drosophila melanogaster, we track inversion frequencies in laboratory crosses to test whether they influence male reproductive success or survival. We find that two of the four tested inversions show significant evidence for the tradeoff examined, with In(3R)K favoring survival and In(3L)Ok favoring male reproduction. In line with the apparent sex-specific fitness effects implied for both of those inversions, In(3L)Ok was also found to be less costly to the viability and/or longevity of males than females, whereas In(3R)K was more beneficial to female survival. Based on this work, we expect that balancing selection on antagonistically pleiotropic traits may provide a significant and underappreciated contribution to the maintenance of natural inversion polymorphism.
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Affiliation(s)
| | - John E. Pool
- Laboratory of Genetics, University of Wisconsin – Madison, USA
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4
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Knief U, Müller IA, Stryjewski KF, Metzler D, Sorenson MD, Wolf JBW. Evolution of Chromosomal Inversions across an Avian Radiation. Mol Biol Evol 2024; 41:msae092. [PMID: 38743589 PMCID: PMC11152452 DOI: 10.1093/molbev/msae092] [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: 01/08/2024] [Revised: 04/05/2024] [Accepted: 05/03/2024] [Indexed: 05/16/2024] Open
Abstract
Chromosomal inversions are structural mutations that can play a prominent role in adaptation and speciation. Inversions segregating across species boundaries (trans-species inversions) are often taken as evidence for ancient balancing selection or adaptive introgression, but can also be due to incomplete lineage sorting. Using whole-genome resequencing data from 18 populations of 11 recognized munia species in the genus Lonchura (N = 176 individuals), we identify four large para- and pericentric inversions ranging in size from 4 to 20 Mb. All four inversions cosegregate across multiple species and predate the numerous speciation events associated with the rapid radiation of this clade across the prehistoric Sahul (Australia, New Guinea) and Bismarck Archipelago. Using coalescent theory, we infer that trans-specificity is improbable for neutrally segregating variation despite substantial incomplete lineage sorting characterizing this young radiation. Instead, the maintenance of all three autosomal inversions (chr1, chr5, and chr6) is best explained by selection acting along ecogeographic clines not observed for the collinear parts of the genome. In addition, the sex chromosome inversion largely aligns with species boundaries and shows signatures of repeated positive selection for both alleles. This study provides evidence for trans-species inversion polymorphisms involved in both adaptation and speciation. It further highlights the importance of informing selection inference using a null model of neutral evolution derived from the collinear part of the genome.
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Affiliation(s)
- Ulrich Knief
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, 82152 Planegg-Martinsried, Germany
- Evolutionary Biology & Ecology, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Ingo A Müller
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, 82152 Planegg-Martinsried, Germany
- Department of Bioinformatics and Genetics, Swedish Museum of Natural History, 11418 Stockholm, Sweden
- Division of Systematics and Evolution, Department of Zoology, Stockholm University, 11418 Stockholm, Sweden
| | | | - Dirk Metzler
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, 82152 Planegg-Martinsried, Germany
| | | | - Jochen B W Wolf
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, 82152 Planegg-Martinsried, Germany
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5
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Charlesworth B. The fitness consequences of genetic divergence between polymorphic gene arrangements. Genetics 2024; 226:iyad218. [PMID: 38147527 PMCID: PMC11090464 DOI: 10.1093/genetics/iyad218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 12/15/2023] [Accepted: 12/20/2023] [Indexed: 12/28/2023] Open
Abstract
Inversions restrict recombination when heterozygous with standard arrangements, but often have few noticeable phenotypic effects. Nevertheless, there are several examples of inversions that can be maintained polymorphic by strong selection under laboratory conditions. A long-standing model for the source of such selection is divergence between arrangements with respect to recessive or partially recessive deleterious mutations, resulting in a selective advantage to heterokaryotypic individuals over homokaryotypes. This paper uses a combination of analytical and numerical methods to investigate this model, for the simple case of an autosomal inversion with multiple independent nucleotide sites subject to mildly deleterious mutations. A complete lack of recombination in heterokaryotypes is assumed, as well as constancy of the frequency of the inversion over space and time. It is shown that a significantly higher mutational load will develop for the less frequent arrangement. A selective advantage to heterokaryotypes is only expected when the two alternative arrangements are nearly equal in frequency, so that their mutational loads are very similar in size. The effects of some Drosophila pseudoobscura polymorphic inversions on fitness traits seem to be too large to be explained by this process, although it may contribute to some of the observed effects. Several population genomic statistics can provide evidence for signatures of a reduced efficacy of selection associated with the rarer of two arrangements, but there is currently little published data that are relevant to the theoretical predictions.
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Affiliation(s)
- Brian Charlesworth
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
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6
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Nunez JCB, Lenhart BA, Bangerter A, Murray CS, Mazzeo GR, Yu Y, Nystrom TL, Tern C, Erickson PA, Bergland AO. A cosmopolitan inversion facilitates seasonal adaptation in overwintering Drosophila. Genetics 2024; 226:iyad207. [PMID: 38051996 PMCID: PMC10847723 DOI: 10.1093/genetics/iyad207] [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: 10/08/2023] [Accepted: 11/28/2023] [Indexed: 12/07/2023] Open
Abstract
Fluctuations in the strength and direction of natural selection through time are a ubiquitous feature of life on Earth. One evolutionary outcome of such fluctuations is adaptive tracking, wherein populations rapidly adapt from standing genetic variation. In certain circumstances, adaptive tracking can lead to the long-term maintenance of functional polymorphism despite allele frequency change due to selection. Although adaptive tracking is likely a common process, we still have a limited understanding of aspects of its genetic architecture and its strength relative to other evolutionary forces such as drift. Drosophila melanogaster living in temperate regions evolve to track seasonal fluctuations and are an excellent system to tackle these gaps in knowledge. By sequencing orchard populations collected across multiple years, we characterized the genomic signal of seasonal demography and identified that the cosmopolitan inversion In(2L)t facilitates seasonal adaptive tracking and shows molecular footprints of selection. A meta-analysis of phenotypic studies shows that seasonal loci within In(2L)t are associated with behavior, life history, physiology, and morphological traits. We identify candidate loci and experimentally link them to phenotype. Our work contributes to our general understanding of fluctuating selection and highlights the evolutionary outcome and dynamics of contemporary selection on inversions.
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Affiliation(s)
- Joaquin C B Nunez
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
- Department of Biology, University of Vermont, 109 Carrigan Drive, Burlington, VT 05405, USA
| | - Benedict A Lenhart
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
| | - Alyssa Bangerter
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
| | - Connor S Murray
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
| | - Giovanni R Mazzeo
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
| | - Yang Yu
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
| | - Taylor L Nystrom
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
| | - Courtney Tern
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
| | - Priscilla A Erickson
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
- Department of Biology, University of Richmond, 138 UR Drive, Richmond, VA 23173, USA
| | - Alan O Bergland
- Department of Biology, University of Virginia, 90 Geldard Drive, Charlottesville, VA 22901, USA
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Berdan EL, Barton NH, Butlin R, Charlesworth B, Faria R, Fragata I, Gilbert KJ, Jay P, Kapun M, Lotterhos KE, Mérot C, Durmaz Mitchell E, Pascual M, Peichel CL, Rafajlović M, Westram AM, Schaeffer SW, Johannesson K, Flatt T. How chromosomal inversions reorient the evolutionary process. J Evol Biol 2023; 36:1761-1782. [PMID: 37942504 DOI: 10.1111/jeb.14242] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 09/13/2023] [Accepted: 10/05/2023] [Indexed: 11/10/2023]
Abstract
Inversions are structural mutations that reverse the sequence of a chromosome segment and reduce the effective rate of recombination in the heterozygous state. They play a major role in adaptation, as well as in other evolutionary processes such as speciation. Although inversions have been studied since the 1920s, they remain difficult to investigate because the reduced recombination conferred by them strengthens the effects of drift and hitchhiking, which in turn can obscure signatures of selection. Nonetheless, numerous inversions have been found to be under selection. Given recent advances in population genetic theory and empirical study, here we review how different mechanisms of selection affect the evolution of inversions. A key difference between inversions and other mutations, such as single nucleotide variants, is that the fitness of an inversion may be affected by a larger number of frequently interacting processes. This considerably complicates the analysis of the causes underlying the evolution of inversions. We discuss the extent to which these mechanisms can be disentangled, and by which approach.
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Affiliation(s)
- Emma L Berdan
- Bioinformatics Core, Department of Biostatistics, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Nicholas H Barton
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Roger Butlin
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
- Ecology and Evolutionary Biology, School of Bioscience, The University of Sheffield, Sheffield, UK
| | - Brian Charlesworth
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Rui Faria
- CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal
| | - Inês Fragata
- CHANGE - Global Change and Sustainability Institute/Animal Biology Department, cE3c - Center for Ecology, Evolution and Environmental Changes, Faculty of Sciences, University of Lisbon, Lisbon, Portugal
| | | | - Paul Jay
- Center for GeoGenetics, University of Copenhagen, Copenhagen, Denmark
| | - Martin Kapun
- Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
- Central Research Laboratories, Natural History Museum of Vienna, Vienna, Austria
| | - Katie E Lotterhos
- Department of Marine and Environmental Sciences, Northeastern University, Boston, Massachusetts, USA
| | - Claire Mérot
- UMR 6553 Ecobio, Université de Rennes, OSUR, CNRS, Rennes, France
| | - Esra Durmaz Mitchell
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- Functional Genomics & Metabolism Research Unit, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Marta Pascual
- Departament de Genètica, Microbiologia i Estadística, Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Spain
| | - Catherine L Peichel
- Division of Evolutionary Ecology, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
| | - Marina Rafajlović
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
- Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
| | - Anja M Westram
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Stephen W Schaeffer
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Kerstin Johannesson
- Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
- Tjärnö Marine Laboratory, Department of Marine Sciences, University of Gothenburg, Strömstad, Sweden
| | - Thomas Flatt
- Department of Biology, University of Fribourg, Fribourg, Switzerland
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8
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Koury SA. Female meiotic drive shapes the distribution of rare inversion polymorphisms in Drosophila melanogaster. Genetics 2023; 225:iyad158. [PMID: 37616566 DOI: 10.1093/genetics/iyad158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 07/11/2023] [Accepted: 08/05/2023] [Indexed: 08/26/2023] Open
Abstract
In all species, new chromosomal inversions are constantly being formed by spontaneous rearrangement and then stochastically eliminated from natural populations. In Drosophila, when new chromosomal inversions overlap with a preexisting inversion in the population, their rate of elimination becomes a function of the relative size, position, and linkage phase of the gene rearrangements. These altered dynamics result from complex meiotic behavior wherein overlapping inversions generate asymmetric dyads that cause both meiotic drive/drag and segmental aneuploidy. In this context, patterns in rare inversion polymorphisms of a natural population can be modeled from the fundamental genetic processes of forming asymmetric dyads via crossing-over in meiosis I and preferential segregation from asymmetric dyads in meiosis II. Here, a mathematical model of crossover-dependent female meiotic drive is developed and parameterized with published experimental data from Drosophila melanogaster laboratory constructs. This mechanism is demonstrated to favor smaller, distal inversions and accelerate the elimination of larger, proximal inversions. Simulated sampling experiments indicate that the paracentric inversions directly observed in natural population surveys of D. melanogaster are a biased subset that both maximizes meiotic drive and minimizes the frequency of lethal zygotes caused by this cytogenetic mechanism. Incorporating this form of selection into a population genetic model accurately predicts the shift in relative size, position, and linkage phase for rare inversions found in this species. The model and analysis presented here suggest that this weak form of female meiotic drive is an important process influencing the genomic distribution of rare inversion polymorphisms.
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Affiliation(s)
- Spencer A Koury
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794-5245, USA
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9
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Charlesworth B. The effects of inversion polymorphisms on patterns of neutral genetic diversity. Genetics 2023; 224:iyad116. [PMID: 37348059 PMCID: PMC10411593 DOI: 10.1093/genetics/iyad116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 02/23/2023] [Accepted: 06/11/2023] [Indexed: 06/24/2023] Open
Abstract
The strong reduction in the frequency of recombination in heterozygotes for an inversion and a standard gene arrangement causes the arrangements to become partially isolated genetically, resulting in sequence divergence between them and changes in the levels of neutral variability at nucleotide sites within each arrangement class. Previous theoretical studies on the effects of inversions on neutral variability have assumed either that the population is panmictic or that it is divided into 2 populations subject to divergent selection. Here, the theory is extended to a model of an arbitrary number of demes connected by migration, using a finite island model with the inversion present at the same frequency in all demes. Recursion relations for mean pairwise coalescent times are used to obtain simple approximate expressions for diversity and divergence statistics for an inversion polymorphism at equilibrium under recombination and drift, and for the approach to equilibrium following the sweep of an inversion to a stable intermediate frequency. The effects of an inversion polymorphism on patterns of linkage disequilibrium are also examined. The reduction in effective recombination rate caused by population subdivision can have significant effects on these statistics. The theoretical results are discussed in relation to population genomic data on inversion polymorphisms, with an emphasis on Drosophila melanogaster. Methods are proposed for testing whether or not inversions are close to recombination-drift equilibrium, and for estimating the rate of recombinational exchange in heterozygotes for inversions; difficulties involved in estimating the ages of inversions are also discussed.
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Affiliation(s)
- Brian Charlesworth
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
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