1
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Wanders K, Chen G, Feng S, Székely T, Urrutia AO. Role-reversed polyandry is associated with faster fast-Z in shorebirds. Proc Biol Sci 2024; 291:20240397. [PMID: 38864333 DOI: 10.1098/rspb.2024.0397] [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: 09/30/2023] [Accepted: 05/14/2024] [Indexed: 06/13/2024] Open
Abstract
In birds, males are homogametic and carry two copies of the Z chromosome ('ZZ'), while females are heterogametic and exhibit a 'ZW' genotype. The Z chromosome evolves at a faster rate than similarly sized autosomes, a phenomenon termed 'fast-Z evolution'. This is thought to be caused by two independent processes-greater Z chromosome genetic drift owing to a reduced effective population size, and stronger Z chromosome positive selection owing to the exposure of partially recessive alleles to selection. Here, we investigate the relative contributions of these processes by considering the effect of role-reversed polyandry on fast-Z in shorebirds, a paraphyletic group of wading birds that exhibit unusually diverse mating systems. We find stronger fast-Z effects under role-reversed polyandry, which is consistent with particularly strong selection on polyandrous females driving the fixation of recessive beneficial alleles. This result contrasts with previous research in birds, which has tended to implicate a primary role of genetic drift in driving fast-Z variation. We suggest that this discrepancy can be interpreted in two ways-stronger sexual selection acting on polyandrous females overwhelms an otherwise central role of genetic drift, and/or sexual antagonism is also contributing significantly to fast-Z and is exacerbated in sexually dimorphic species.
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Affiliation(s)
- Kees Wanders
- Department of Life Sciences, Milner Centre for Evolution, University of Bath , Bath, UK
- Department of Evolutionary Zoology and Human Biology, HUN-REN-DE Reproductive strategies Research Group, University of Debrecen , Debrecen, Hungary
- Natural History Museum of Denmark, University of Copenhagen , Copenhagen, Denmark
| | - Guangji Chen
- Center for Evolutionary & Organismal Biology, Liangzhu Laboratory, Department of General Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine , Hangzhou, People's Republic of China
- BGI Research , Wuhan, People's Republic of China
- College of Life Sciences, University of Chinese Academy of Sciences , Beijing, People's Republic of China
| | - Shaohong Feng
- Center for Evolutionary & Organismal Biology, Liangzhu Laboratory, Department of General Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine , Hangzhou, People's Republic of China
| | - Tamás Székely
- Department of Life Sciences, Milner Centre for Evolution, University of Bath , Bath, UK
- Department of Evolutionary Zoology and Human Biology, HUN-REN-DE Reproductive strategies Research Group, University of Debrecen , Debrecen, Hungary
- Debrecen Biodiversity Centre, University of Debrecen , Debrecen, Hungary
| | - Arraxi O Urrutia
- Department of Life Sciences, Milner Centre for Evolution, University of Bath , Bath, UK
- Instituto de Ecologia, UNAM , Mexico City, Mexico
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2
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Rossi M, Hausmann AE, Alcami P, Moest M, Roussou R, Van Belleghem SM, Wright DS, Kuo CY, Lozano-Urrego D, Maulana A, Melo-Flórez L, Rueda-Muñoz G, McMahon S, Linares M, Osman C, McMillan WO, Pardo-Diaz C, Salazar C, Merrill RM. Adaptive introgression of a visual preference gene. Science 2024; 383:1368-1373. [PMID: 38513020 PMCID: PMC7616200 DOI: 10.1126/science.adj9201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 01/30/2024] [Indexed: 03/23/2024]
Abstract
Visual preferences are important drivers of mate choice and sexual selection, but little is known of how they evolve at the genetic level. In this study, we took advantage of the diversity of bright warning patterns displayed by Heliconius butterflies, which are also used during mate choice. Combining behavioral, population genomic, and expression analyses, we show that two Heliconius species have evolved the same preferences for red patterns by exchanging genetic material through hybridization. Neural expression of regucalcin1 correlates with visual preference across populations, and disruption of regucalcin1 with CRISPR-Cas9 impairs courtship toward conspecific females, providing a direct link between gene and behavior. Our results support a role for hybridization during behavioral evolution and show how visually guided behaviors contributing to adaptation and speciation are encoded within the genome.
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Affiliation(s)
- Matteo Rossi
- Faculty of Biology, Ludwig Maximilian University; Munich, Germany
| | | | - Pepe Alcami
- Faculty of Biology, Ludwig Maximilian University; Munich, Germany
| | - Markus Moest
- Department of Ecology and Research Department for Limnology, Mondsee; University of Innsbruck, Innsbruck, Austria
| | - Rodaria Roussou
- Faculty of Biology, Ludwig Maximilian University; Munich, Germany
| | | | | | - Chi-Yun Kuo
- Faculty of Biology, Ludwig Maximilian University; Munich, Germany
- Smithsonian Tropical Research Institute; Gamboa, Panama
| | - Daniela Lozano-Urrego
- Faculty of Biology, Ludwig Maximilian University; Munich, Germany
- Faculty of Natural Sciences, Universidad del Rosario; Bogotá, Colombia
| | - Arif Maulana
- Faculty of Biology, Ludwig Maximilian University; Munich, Germany
| | - Lina Melo-Flórez
- Faculty of Biology, Ludwig Maximilian University; Munich, Germany
- Faculty of Natural Sciences, Universidad del Rosario; Bogotá, Colombia
| | - Geraldine Rueda-Muñoz
- Faculty of Biology, Ludwig Maximilian University; Munich, Germany
- Faculty of Natural Sciences, Universidad del Rosario; Bogotá, Colombia
| | - Saoirse McMahon
- Faculty of Biology, Ludwig Maximilian University; Munich, Germany
| | - Mauricio Linares
- Faculty of Natural Sciences, Universidad del Rosario; Bogotá, Colombia
| | - Christof Osman
- Faculty of Biology, Ludwig Maximilian University; Munich, Germany
| | | | | | - Camilo Salazar
- Faculty of Natural Sciences, Universidad del Rosario; Bogotá, Colombia
| | - Richard M. Merrill
- Faculty of Biology, Ludwig Maximilian University; Munich, Germany
- Smithsonian Tropical Research Institute; Gamboa, Panama
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3
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Darolti I, Fong LJM, Sandkam BA, Metzger DCH, Mank JE. Sex chromosome heteromorphism and the Fast-X effect in poeciliids. Mol Ecol 2023; 32:4599-4609. [PMID: 37309716 DOI: 10.1111/mec.17048] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/29/2023] [Accepted: 05/31/2023] [Indexed: 06/14/2023]
Abstract
Fast-X evolution has been observed in a range of heteromorphic sex chromosomes. However, it remains unclear how early in the process of sex chromosome differentiation the Fast-X effect becomes detectible. Recently, we uncovered an extreme variation in sex chromosome heteromorphism across poeciliid fish species. The common guppy, Poecilia reticulata, Endler's guppy, P. wingei, swamp guppy, P. picta and para guppy, P. parae, appear to share the same XY system and exhibit a remarkable range of heteromorphism. Species outside this group lack this sex chromosome system. We combined analyses of sequence divergence and polymorphism data across poeciliids to investigate X chromosome evolution as a function of hemizygosity and reveal the causes for Fast-X effects. Consistent with the extent of Y degeneration in each species, we detect higher rates of divergence on the X relative to autosomes, a signal of Fast-X evolution, in P. picta and P. parae, species with high levels of X hemizygosity in males. In P. reticulata, which exhibits largely homomorphic sex chromosomes and little evidence of hemizygosity, we observe no change in the rate of evolution of X-linked relative to autosomal genes. In P. wingei, the species with intermediate sex chromosome differentiation, we see an increase in the rate of nonsynonymous substitutions on the older stratum of divergence only. We also use our comparative approach to test for the time of origin of the sex chromosomes in this clade. Taken together, our study reveals an important role of hemizygosity in Fast-X evolution.
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Affiliation(s)
- Iulia Darolti
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Lydia J M Fong
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Benjamin A Sandkam
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York, USA
| | - David C H Metzger
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Judith E Mank
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
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4
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Mrnjavac A, Khudiakova KA, Barton NH, Vicoso B. Slower-X: reduced efficiency of selection in the early stages of X chromosome evolution. Evol Lett 2023; 7:4-12. [PMID: 37065438 PMCID: PMC10091493 DOI: 10.1093/evlett/qrac004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/08/2022] [Accepted: 12/17/2022] [Indexed: 02/04/2023] Open
Abstract
Abstract
Differentiated X chromosomes are expected to have higher rates of adaptive divergence than autosomes, if new beneficial mutations are recessive (the “faster-X effect”), largely because these mutations are immediately exposed to selection in males. The evolution of X chromosomes after they stop recombining in males, but before they become hemizygous, has not been well explored theoretically. We use the diffusion approximation to infer substitution rates of beneficial and deleterious mutations under such a scenario. Our results show that selection is less efficient on diploid X loci than on autosomal and hemizygous X loci under a wide range of parameters. This “slower-X” effect is stronger for genes affecting primarily (or only) male fitness, and for sexually antagonistic genes. These unusual dynamics suggest that some of the peculiar features of X chromosomes, such as the differential accumulation of genes with sex-specific functions, may start arising earlier than previously appreciated.
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Affiliation(s)
- Andrea Mrnjavac
- Institute of Science and Technology Austria , Am Campus 1, 3400 Klosterneuburg , Austria
| | - Ksenia A Khudiakova
- Institute of Science and Technology Austria , Am Campus 1, 3400 Klosterneuburg , Austria
| | - Nicholas H Barton
- Institute of Science and Technology Austria , Am Campus 1, 3400 Klosterneuburg , Austria
| | - Beatriz Vicoso
- Institute of Science and Technology Austria , Am Campus 1, 3400 Klosterneuburg , Austria
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5
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Parker DJ, Jaron KS, Dumas Z, Robinson‐Rechavi M, Schwander T. X chromosomes show relaxed selection and complete somatic dosage compensation across
Timema
stick insect species. J Evol Biol 2022; 35:1734-1750. [PMID: 35933721 PMCID: PMC10087215 DOI: 10.1111/jeb.14075] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 05/06/2022] [Accepted: 07/14/2022] [Indexed: 11/29/2022]
Abstract
Sex chromosomes have evolved repeatedly across the tree of life. As they are present in different copy numbers in males and females, they are expected to experience different selection pressures than the autosomes, with consequences including a faster rate of evolution, increased accumulation of sexually antagonistic alleles and the evolution of dosage compensation. Whether these consequences are general or linked to idiosyncrasies of specific taxa is not clear as relatively few taxa have been studied thus far. Here, we use whole-genome sequencing to identify and characterize the evolution of the X chromosome in five species of Timema stick insects with XX:X0 sex determination. The X chromosome had a similar size (approximately 12% of the genome) and gene content across all five species, suggesting that the X chromosome originated prior to the diversification of the genus. Genes on the X showed evidence of relaxed selection (elevated dN/dS) and a slower evolutionary rate (dN + dS) than genes on the autosomes, likely due to sex-biased mutation rates. Genes on the X also showed almost complete dosage compensation in somatic tissues (heads and legs), but dosage compensation was absent in the reproductive tracts. Contrary to prediction, sex-biased genes showed little enrichment on the X, suggesting that the advantage X-linkage provides to the accumulation of sexually antagonistic alleles is weak. Overall, we found the consequences of X-linkage on gene sequences and expression to be similar across Timema species, showing the characteristics of the X chromosome are surprisingly consistent over 30 million years of evolution.
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Affiliation(s)
- Darren J. Parker
- Department of Ecology and Evolution University of Lausanne Lausanne Switzerland
- Swiss Institute of Bioinformatics Lausanne Switzerland
- School of Natural Sciences Bangor University Bangor UK
| | - Kamil S. Jaron
- Department of Ecology and Evolution University of Lausanne Lausanne Switzerland
- Swiss Institute of Bioinformatics Lausanne Switzerland
- School of Biological Sciences Institute of Evolutionary Biology University of Edinburgh Edinburgh UK
| | - Zoé Dumas
- Department of Ecology and Evolution University of Lausanne Lausanne Switzerland
| | - Marc Robinson‐Rechavi
- Department of Ecology and Evolution University of Lausanne Lausanne Switzerland
- Swiss Institute of Bioinformatics Lausanne Switzerland
| | - Tanja Schwander
- Department of Ecology and Evolution University of Lausanne Lausanne Switzerland
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6
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Hanly JJ, Livraghi L, Heryanto C, McMillan WO, Jiggins CD, Gilbert LE, Martin A. A large deletion at the cortex locus eliminates butterfly wing patterning. G3 GENES|GENOMES|GENETICS 2022; 12:6517782. [PMID: 35099556 PMCID: PMC8982378 DOI: 10.1093/g3journal/jkac021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 01/21/2022] [Indexed: 11/21/2022]
Abstract
As the genetic basis of natural and domesticated variation has been described in recent years, a number of hotspot genes have been repeatedly identified as the targets of selection, Heliconius butterflies display a spectacular diversity of pattern variants in the wild and the genetic basis of these patterns has been well-described. Here, we sought to identify the mechanism behind an unusual pattern variant that is instead found in captivity, the ivory mutant, in which all scales on both the wings and body become white or yellow. Using a combination of autozygosity mapping and coverage analysis from 37 captive individuals, we identify a 78-kb deletion at the cortex wing patterning locus, a gene which has been associated with wing pattern evolution in H. melpomene and 10 divergent lepidopteran species. This deletion is undetected among 458 wild Heliconius genomes samples, and its dosage explains both homozygous and heterozygous ivory phenotypes found in captivity. The deletion spans a large 5′ region of the cortex gene that includes a facultative 5′UTR exon detected in larval wing disk transcriptomes. CRISPR mutagenesis of this exon replicates the wing phenotypes from coding knock-outs of cortex, consistent with a functional role of ivory-deleted elements in establishing scale color fate. Population demographics reveal that the stock giving rise to the ivory mutant has a mixed origin from across the wild range of H. melpomene, and supports a scenario where the ivory mutation occurred after the introduction of cortex haplotypes from Ecuador. Homozygotes for the ivory deletion are inviable while heterozygotes are the targets of artificial selection, joining 40 other examples of allelic variants that provide heterozygous advantage in animal populations under artificial selection by fanciers and breeders. Finally, our results highlight the promise of autozygosity and association mapping for identifying the genetic basis of aberrant mutations in captive insect populations.
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Affiliation(s)
- Joseph J Hanly
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
- Smithsonian Tropical Research Institute, Panama 0843-03092, Republic of Panama
| | - Luca Livraghi
- Smithsonian Tropical Research Institute, Panama 0843-03092, Republic of Panama
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Christa Heryanto
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
| | - W Owen McMillan
- Smithsonian Tropical Research Institute, Panama 0843-03092, Republic of Panama
| | - Chris D Jiggins
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Lawrence E Gilbert
- Department of Integrative Biology, University of Texas, Austin, TX 78712, USA
| | - Arnaud Martin
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
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7
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Rosser N, Edelman NB, Queste LM, Nelson M, Seixas F, Dasmahapatra KK, Mallet J. Complex basis of hybrid female sterility and Haldane's rule in Heliconius butterflies: Z-linkage and epistasis. Mol Ecol 2021; 31:959-977. [PMID: 34779079 DOI: 10.1111/mec.16272] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 09/14/2021] [Accepted: 09/27/2021] [Indexed: 12/19/2022]
Abstract
Hybrids between species are often sterile or inviable. Hybrid unfitness usually evolves first in the heterogametic sex-a pattern known as Haldane's rule. The genetics of Haldane's rule have been extensively studied in species where the male is the heterogametic (XX/XY) sex, but its basis in taxa where the female is heterogametic (ZW/ZZ), such as Lepidoptera and birds, is largely unknown. Here, we analyse a new case of female hybrid sterility between geographic subspecies of Heliconius pardalinus. The two subspecies mate freely in captivity, but female F1 hybrids in both directions of cross are sterile. Sterility is due to arrested development of oocytes after they become differentiated from nurse cells, but before yolk deposition. We backcrossed fertile male F1 hybrids to parental females and mapped quantitative trait loci (QTLs) for female sterility. We also identified genes differentially expressed in the ovary as a function of oocyte development. The Z chromosome has a major effect, similar to the 'large X effect' in Drosophila, with strong epistatic interactions between loci at either end of the Z chromosome, and between the Z chromosome and autosomal loci on chromosomes 8 and 20. By intersecting the list of genes within these QTLs with those differentially expressed in sterile and fertile hybrids, we identified three candidate genes with relevant phenotypes. This study is the first to characterize hybrid sterility using genome mapping in the Lepidoptera and shows that it is produced by multiple complex epistatic interactions often involving the sex chromosome, as predicted by the dominance theory of Haldane's rule.
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Affiliation(s)
- Neil Rosser
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA.,Department of Biology, University of York, York, UK
| | - Nathaniel B Edelman
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA.,Yale Institute for Biospheric Studies, Yale University, New Haven, Connecticut, USA.,Yale School for the Environment, Yale University, New Haven, Connecticut, USA
| | | | | | - Fernando Seixas
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | | | - James Mallet
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
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8
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Mongue AJ, Hansen ME, Walters JR. Support for faster and more adaptive Z chromosome evolution in two divergent lepidopteran lineages. Evolution 2021; 76:332-345. [PMID: 34463346 PMCID: PMC9291949 DOI: 10.1111/evo.14341] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 07/21/2021] [Accepted: 08/06/2021] [Indexed: 12/14/2022]
Abstract
The rateof divergence for Z or X chromosomes is usually observed to be greater than autosomes, but the proposed evolutionary causes for this pattern vary, as do empirical results from diverse taxa. Even among moths and butterflies (Lepidoptera), which generally share a single-origin Z chromosome, the handful of available studies give mixed support for faster or more adaptive evolution of the Z chromosome, depending on the species assayed. Here, we examine the molecular evolution of Z chromosomes in two additional lepidopteran species: the Carolina sphinx moth and the monarch butterfly, the latter of which possesses a recent chromosomal fusion yielding a segment of newly Z-linked DNA. We find evidence for both faster and more adaptive Z chromosome evolution in both species, although this effect is strongest in the neo-Z portion of the monarch sex chromosome. The neo-Z is less male-biased than expected of a Z chromosome, and unbiased and female-biased genes drive the signal for adaptive evolution here. Together these results suggest that male-biased gene accumulation and haploid selection have opposing effects on long-term rates of adaptation and may help explain the discrepancies in previous findings as well as the repeated evolution of neo-sex chromosomes in Lepidoptera.
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Affiliation(s)
- Andrew J Mongue
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, 66045.,Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, EH93FL, United Kingdom
| | - Megan E Hansen
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, 66045
| | - James R Walters
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, 66045
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9
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Pazhenkova EA, Lukhtanov VA. Genomic introgression from a distant congener in the Levant fritillary butterfly, Melitaea acentria. Mol Ecol 2021; 30:4819-4832. [PMID: 34288183 DOI: 10.1111/mec.16085] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 07/14/2021] [Accepted: 07/15/2021] [Indexed: 12/12/2022]
Abstract
Introgressive hybridization is more common in nature than previously thought, and its role and creative power in evolution is hotly discussed but not completely understood. Introgression occurs more frequently in sympatry between recently diverged taxa, or when the speciation process has not yet been completed. However, there are relatively few documented cases of hybridization that erodes reproductive barriers between distantly related species. Here, we use whole genome and mitochondrial data to examine how introgression from a distant congener affects pattern of genetic differentiation in the Levant fritillary butterfly Melitaea acentria. We show that this local taxon has evolved as a peripatric geographic isolate of the widespread Melitaea persea, and that there has been significant unidirectional gene flow from the sympatric, nonclosely related Melitaea didyma to M. acentria. We found direct evidence of ongoing sporadic hybridization between M. didyma and M. acentria, which are separated by at least 5 million years of independent evolution. Elevated differentiation and lower level of introgression on the sex Z chromosome compared to autosomes suggest that the Z chromosome has accumulated loci acting as intrinsic postzygotic barriers. Our results show that introgression from M. didyma has been an additional source of nucleotide diversity in the M. acentria population, providing material for drift and selection.
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Affiliation(s)
- Elena A Pazhenkova
- Department of Entomology, St. Petersburg State University, St. Petersburg, Russia.,Department of Karyosystematics, Zoological Institute of Russian Academy of Sciences, St. Petersburg, Russia
| | - Vladimir A Lukhtanov
- Department of Karyosystematics, Zoological Institute of Russian Academy of Sciences, St. Petersburg, Russia
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10
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Neural divergence and hybrid disruption between ecologically isolated Heliconius butterflies. Proc Natl Acad Sci U S A 2021; 118:2015102118. [PMID: 33547240 DOI: 10.1073/pnas.2015102118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The importance of behavioral evolution during speciation is well established, but we know little about how this is manifest in sensory and neural systems. A handful of studies have linked specific neural changes to divergence in host or mate preferences associated with speciation. However, the degree to which brains are adapted to local environmental conditions, and whether this contributes to reproductive isolation between close relatives that have diverged in ecology, remains unknown. Here, we examine divergence in brain morphology and neural gene expression between closely related, but ecologically distinct, Heliconius butterflies. Despite ongoing gene flow, sympatric species pairs within the melpomene-cydno complex are consistently separated across a gradient of open to closed forest and decreasing light intensity. By generating quantitative neuroanatomical data for 107 butterflies, we show that Heliconius melpomene and Heliconius cydno clades have substantial shifts in brain morphology across their geographic range, with divergent structures clustered in the visual system. These neuroanatomical differences are mirrored by extensive divergence in neural gene expression. Differences in both neural morphology and gene expression are heritable, exceed expected rates of neutral divergence, and result in intermediate traits in first-generation hybrid offspring. Strong evidence of divergent selection implies local adaptation to distinct selective optima in each parental microhabitat, suggesting the intermediate traits of hybrids are poorly matched to either condition. Neural traits may therefore contribute to coincident barriers to gene flow, thereby helping to facilitate speciation.
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11
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Seixas FA, Edelman NB, Mallet J. Synteny-Based Genome Assembly for 16 Species of Heliconius Butterflies, and an Assessment of Structural Variation across the Genus. Genome Biol Evol 2021; 13:6207971. [PMID: 33792688 PMCID: PMC8290116 DOI: 10.1093/gbe/evab069] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2021] [Indexed: 12/11/2022] Open
Abstract
Heliconius butterflies (Lepidoptera: Nymphalidae) are a group of 48 neotropical species widely studied in evolutionary research. Despite the wealth of genomic data generated in past years, chromosomal level genome assemblies currently exist for only two species, Heliconius melpomene and Heliconius erato, each a representative of one of the two major clades of the genus. Here, we use these reference genomes to improve the contiguity of previously published draft genome assemblies of 16 Heliconius species. Using a reference-assisted scaffolding approach, we place and order the scaffolds of these genomes onto chromosomes, resulting in 95.7-99.9% of their genomes anchored to chromosomes. Genome sizes are somewhat variable among species (270-422 Mb) and in one small group of species (Heliconius hecale, Heliconius elevatus, and Heliconius pardalinus) expansions in genome size are driven mainly by repetitive sequences that map to four small regions in the H. melpomene reference genome. Genes from these repeat regions show an increase in exon copy number, an absence of internal stop codons, evidence of constraint on nonsynonymous changes, and increased expression, all of which suggest that at least some of the extra copies are functional. Finally, we conducted a systematic search for inversions and identified five moderately large inversions fixed between the two major Heliconius clades. We infer that one of these inversions was transferred by introgression between the lineages leading to the erato/sara and burneyi/doris clades. These reference-guided assemblies represent a major improvement in Heliconius genomic resources that enable further genetic and evolutionary discoveries in this genus.
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Affiliation(s)
- Fernando A Seixas
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Nathaniel B Edelman
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA.,Yale Institute for Biospheric Studies, Yale University, New Haven, Connecticut, USA
| | - James Mallet
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
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12
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Schield DR, Perry BW, Nikolakis ZL, Mackessy SP, Castoe TA. Population Genomic Analyses Confirm Male-Biased Mutation Rates in Snakes. J Hered 2021; 112:221-227. [PMID: 33502475 DOI: 10.1093/jhered/esab005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/21/2021] [Indexed: 11/13/2022] Open
Abstract
Male-biased mutation rates occur in a diverse array of organisms. The ratio of male-to-female mutation rate may have major ramifications for evolution across the genome, and for sex-linked genes in particular. In ZW species, the Z chromosome is carried by males two-thirds of the time, leading to the prediction that male-biased mutation rates will have a disproportionate effect on the evolution of Z-linked genes relative to autosomes and the W chromosome. Colubroid snakes (including colubrids, elapids, and viperids) have ZW sex determination, yet male-biased mutation rates have not been well studied in this group. Here we analyze a population genomic dataset from rattlesnakes to quantify genetic variation within and genetic divergence between species. We use a new method for unbiased estimation of population genetic summary statistics to compare variation between the Z chromosome and autosomes and to calculate net nucleotide differentiation between species. We find evidence for a 2.03-fold greater mutation rate in male rattlesnakes relative to females, corresponding to an average μZ/μA ratio of 1.1. Our results from snakes are quantitatively similar to birds, suggesting that male-biased mutation rates may be a common feature across vertebrate lineages with ZW sex determination.
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Affiliation(s)
- Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, TX.,Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, TX
| | | | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, CO
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, TX
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13
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Hayes K, Barton HJ, Zeng K. A Study of Faster-Z Evolution in the Great Tit (Parus major). Genome Biol Evol 2021; 12:210-222. [PMID: 32119100 PMCID: PMC7144363 DOI: 10.1093/gbe/evaa044] [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] [Accepted: 02/26/2020] [Indexed: 12/17/2022] Open
Abstract
Sex chromosomes contribute substantially to key evolutionary processes such as speciation and adaptation. Several theories suggest that evolution could occur more rapidly on sex chromosomes, but currently our understanding of whether and how this occurs is limited. Here, we present an analysis of the great tit (Parus major) genome, aiming to detect signals of faster-Z evolution. We find mixed evidence of faster divergence on the Z chromosome than autosomes, with significantly higher divergence being found in ancestral repeats, but not at 4- or 0-fold degenerate sites. Interestingly, some 4-fold sites appear to be selectively constrained, which may mislead analyses that use these sites as the neutral reference (e.g., dN/dS). Consistent with other studies in birds, the mutation rate is significantly higher in males than females, and the long-term Z-to-autosome effective population size ratio is only 0.5, significantly lower than the expected value of 0.75. These are indicative of male-driven evolution and high variance in male reproductive success, respectively. We find no evidence for an increased efficacy of positive selection on the Z chromosome. In contrast, the Z chromosome in great tits appears to be affected by increased genetic drift, which has led to detectable signals of weakened intensity of purifying selection. These results provide further evidence that the Z chromosome often has a low effective population size, and that this has important consequences for its evolution. They also highlight the importance of considering multiple factors that can affect the rate of evolution and effective population sizes of sex chromosomes.
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Affiliation(s)
- Kai Hayes
- Department of Animal and Plant Sciences, University of Sheffield, United Kingdom
| | - Henry J Barton
- Department of Animal and Plant Sciences, University of Sheffield, United Kingdom.,Organismal and Evolutionary Biology Research Program, University of Helsinki, Finland
| | - Kai Zeng
- Department of Animal and Plant Sciences, University of Sheffield, United Kingdom
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14
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Darragh K, Orteu A, Black D, Byers KJRP, Szczerbowski D, Warren IA, Rastas P, Pinharanda A, Davey JW, Fernanda Garza S, Abondano Almeida D, Merrill RM, McMillan WO, Schulz S, Jiggins CD. A novel terpene synthase controls differences in anti-aphrodisiac pheromone production between closely related Heliconius butterflies. PLoS Biol 2021; 19:e3001022. [PMID: 33465061 PMCID: PMC7815096 DOI: 10.1371/journal.pbio.3001022] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 11/30/2020] [Indexed: 02/07/2023] Open
Abstract
Plants and insects often use the same compounds for chemical communication, but not much is known about the genetics of convergent evolution of chemical signals. The terpene (E)-β-ocimene is a common component of floral scent and is also used by the butterfly Heliconius melpomene as an anti-aphrodisiac pheromone. While the biosynthesis of terpenes has been described in plants and microorganisms, few terpene synthases (TPSs) have been identified in insects. Here, we study the recent divergence of 2 species, H. melpomene and Heliconius cydno, which differ in the presence of (E)-β-ocimene; combining linkage mapping, gene expression, and functional analyses, we identify 2 novel TPSs. Furthermore, we demonstrate that one, HmelOS, is able to synthesise (E)-β-ocimene in vitro. We find no evidence for TPS activity in HcydOS (HmelOS ortholog of H. cydno), suggesting that the loss of (E)-β-ocimene in this species is the result of coding, not regulatory, differences. The TPS enzymes we discovered are unrelated to previously described plant and insect TPSs, demonstrating that chemical convergence has independent evolutionary origins. Plants and insects often use the same compounds for chemical communication, but little is known about the convergent evolution of such chemical signals. This study identifies a novel terpene synthase involved in production of an anti-aphrodisiac pheromone by the butterfly Heliconius melpomene. This enzyme is unrelated to other insect terpene synthases, providing evidence that the ability to synthesise terpenes has arisen multiple times independently within the insects.
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Affiliation(s)
- Kathy Darragh
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
- Smithsonian Tropical Research Institute, Panamá, Panamá
- * E-mail:
| | - Anna Orteu
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Daniella Black
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
- School of Biology, University of St Andrews, St Andrews, United Kingdom
| | - Kelsey J. R. P. Byers
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
- Smithsonian Tropical Research Institute, Panamá, Panamá
| | - Daiane Szczerbowski
- Institute of Organic Chemistry, Department of Life Sciences, Technische Universität Braunschweig, Braunschweig, Germany
| | - Ian A. Warren
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Pasi Rastas
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Ana Pinharanda
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - John W. Davey
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | | | | | - Richard M. Merrill
- Smithsonian Tropical Research Institute, Panamá, Panamá
- Division of Evolutionary Biology, Ludwig-Maximilians-Universität München, Munich, Germany
| | | | - Stefan Schulz
- Institute of Organic Chemistry, Department of Life Sciences, Technische Universität Braunschweig, Braunschweig, Germany
| | - Chris D. Jiggins
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
- Smithsonian Tropical Research Institute, Panamá, Panamá
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15
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Rossi M, Hausmann AE, Thurman TJ, Montgomery SH, Papa R, Jiggins CD, McMillan WO, Merrill RM. Visual mate preference evolution during butterfly speciation is linked to neural processing genes. Nat Commun 2020; 11:4763. [PMID: 32958765 PMCID: PMC7506007 DOI: 10.1038/s41467-020-18609-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 08/26/2020] [Indexed: 02/06/2023] Open
Abstract
Many animal species remain separate not because their individuals fail to produce viable hybrids but because they "choose" not to mate. However, we still know very little of the genetic mechanisms underlying changes in these mate preference behaviours. Heliconius butterflies display bright warning patterns, which they also use to recognize conspecifics. Here, we couple QTL for divergence in visual preference behaviours with population genomic and gene expression analyses of neural tissue (central brain, optic lobes and ommatidia) across development in two sympatric Heliconius species. Within a region containing 200 genes, we identify five genes that are strongly associated with divergent visual preferences. Three of these have previously been implicated in key components of neural signalling (specifically an ionotropic glutamate receptor and two regucalcins), and overall our candidates suggest shifts in behaviour involve changes in visual integration or processing. This would allow preference evolution without altering perception of the wider environment.
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Affiliation(s)
- Matteo Rossi
- Division of Evolutionary Biology, LMU, Munich, Germany.
- Smithsonian Tropical Research Institute, Panama City, Panama.
| | | | - Timothy J Thurman
- Smithsonian Tropical Research Institute, Panama City, Panama
- Division of Biological Sciences, University of Montana, Montana, USA
| | | | - Riccardo Papa
- Smithsonian Tropical Research Institute, Panama City, Panama
- Department of Biology, University of Puerto Rico, San Juan, Puerto Rico
- Molecular Sciences and Research Center, University of Puerto Rico, San Juan, Puerto Rico
| | - Chris D Jiggins
- Smithsonian Tropical Research Institute, Panama City, Panama
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - W Owen McMillan
- Smithsonian Tropical Research Institute, Panama City, Panama
| | - Richard M Merrill
- Division of Evolutionary Biology, LMU, Munich, Germany.
- Smithsonian Tropical Research Institute, Panama City, Panama.
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16
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Abstract
The faster-X effect, namely the rapid evolution of protein-coding genes on the X chromosome, has been widely reported in metazoans. However, the prevalence of this phenomenon across diverse systems and its potential causes remain largely unresolved. Analysis of sex-biased genes may elucidate its possible mechanisms: for example, in systems with X/Y males a more pronounced faster-X effect in male-biased genes than in female-biased or unbiased genes may suggest fixation of recessive beneficial mutations rather than genetic drift. Further, theory predicts that the faster-X effect should be promoted by X chromosome dosage compensation. Here, we asked whether we could detect a faster-X effect in genes of the beetle Tribolium castaneum (and T. freemani orthologs), which has X/Y sex-determination and heterogametic males. Our comparison of protein sequence divergence (dN/dS) on the X chromosome vs. autosomes indicated a rarely observed absence of a faster-X effect in this organism. Further, analyses of sex-biased gene expression revealed that the X chromosome was particularly highly enriched for ovary-biased genes, which evolved slowly. In addition, an evaluation of male X chromosome dosage compensation in the gonads and in non-gonadal somatic tissues indicated a striking lack of compensation in the testis. This under-expression in testis may limit fixation of recessive beneficial X-linked mutations in genes transcribed in these male sex organs. Taken together, these beetles provide an example of the absence of a faster-X effect on protein evolution in a metazoan, that may result from two plausible factors, strong constraint on abundant X-linked ovary-biased genes and a lack of gonadal dosage compensation.
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17
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Talla V, Soler L, Kawakami T, Dincă V, Vila R, Friberg M, Wiklund C, Backström N. Dissecting the Effects of Selection and Mutation on Genetic Diversity in Three Wood White (Leptidea) Butterfly Species. Genome Biol Evol 2019; 11:2875-2886. [PMID: 31580421 PMCID: PMC6795238 DOI: 10.1093/gbe/evz212] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2019] [Indexed: 12/12/2022] Open
Abstract
The relative role of natural selection and genetic drift in evolution is a major topic of debate in evolutionary biology. Most knowledge spring from a small group of organisms and originate from before it was possible to generate genome-wide data on genetic variation. Hence, it is necessary to extend to a larger number of taxonomic groups, descriptive and hypothesis-based research aiming at understanding the proximate and ultimate mechanisms underlying both levels of genetic polymorphism and the efficiency of natural selection. In this study, we used data from 60 whole-genome resequenced individuals of three cryptic butterfly species (Leptidea sp.), together with novel gene annotation information and population recombination data. We characterized the overall prevalence of natural selection and investigated the effects of mutation and linked selection on regional variation in nucleotide diversity. Our analyses showed that genome-wide diversity and rate of adaptive substitutions were comparatively low, whereas nonsynonymous to synonymous polymorphism and substitution levels were comparatively high in Leptidea, suggesting small long-term effective population sizes. Still, negative selection on linked sites (background selection) has resulted in reduced nucleotide diversity in regions with relatively high gene density and low recombination rate. We also found a significant effect of mutation rate variation on levels of polymorphism. Finally, there were considerable population differences in levels of genetic diversity and pervasiveness of selection against slightly deleterious alleles, in line with expectations from differences in estimated effective population sizes.
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Affiliation(s)
- Venkat Talla
- Department of Evolutionary Biology, Evolutionary Biology Centre (EBC), Uppsala University, Sweden
| | - Lucile Soler
- Department of Medical Biochemistry and Microbiology, National Bioinformatics Infrastructure Sweden (NBIS), Science for Life Laboratory, Uppsala, Sweden
| | - Takeshi Kawakami
- Department of Evolutionary Biology, Evolutionary Biology Centre (EBC), Uppsala University, Sweden
| | - Vlad Dincă
- Department of Ecology and Genetics, University of Oulu, Finland
| | - Roger Vila
- Institut de Biologia Evolutiva (CSIC-UPF), Barcelona, Spain
| | - Magne Friberg
- Department of Biology, Biodiversity Unit, Lund University, Sweden
| | - Christer Wiklund
- Department of Zoology, Division of Ecology, Stockholm University, Sweden
| | - Niclas Backström
- Department of Evolutionary Biology, Evolutionary Biology Centre (EBC), Uppsala University, Sweden
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18
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Pinharanda A, Rousselle M, Martin SH, Hanly JJ, Davey JW, Kumar S, Galtier N, Jiggins CD. Sexually dimorphic gene expression and transcriptome evolution provide mixed evidence for a fast-Z effect in Heliconius. J Evol Biol 2019; 32:194-204. [PMID: 30523653 PMCID: PMC6850379 DOI: 10.1111/jeb.13410] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 11/06/2018] [Accepted: 11/27/2018] [Indexed: 12/30/2022]
Abstract
Sex chromosomes have different evolutionary properties compared to autosomes due to their hemizygous nature. In particular, recessive mutations are more readily exposed to selection, which can lead to faster rates of molecular evolution. Here, we report patterns of gene expression and molecular evolution for a group of butterflies. First, we improve the completeness of the Heliconius melpomene reference annotation, a neotropical butterfly with a ZW sex determination system. Then, we analyse RNA from male and female whole abdomens and sequence female ovary and gut tissue to identify sex‐ and tissue‐specific gene expression profiles in H. melpomene. Using these expression profiles, we compare (a) sequence divergence and polymorphism; (b) the strength of positive and negative selection; and (c) rates of adaptive evolution, for Z and autosomal genes between two species of Heliconius butterflies, H. melpomene and H. erato. We show that the rate of adaptive substitutions is higher for Z than autosomal genes, but contrary to expectation, it is also higher for male‐biased than female‐biased genes. Additionally, we find no significant increase in the rate of adaptive evolution or purifying selection on genes expressed in ovary tissue, a heterogametic‐specific tissue. Our results contribute to a growing body of literature from other ZW systems that also provide mixed evidence for a fast‐Z effect where hemizygosity influences the rate of adaptive substitutions.
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Affiliation(s)
- Ana Pinharanda
- Department of Zoology, University of Cambridge, Cambridge, UK.,Department of Ecology and Evolutionary Biology and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey
| | - Marjolaine Rousselle
- UMR 5554 Institut des Sciences de l'Evolution, CNRS, IRD, EPHE, Université de Montpellier, Montpellier, France
| | - Simon H Martin
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Joe J Hanly
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - John W Davey
- Department of Zoology, University of Cambridge, Cambridge, UK.,Department of Biology, University of York, York, UK
| | - Sujai Kumar
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - Nicolas Galtier
- Department of Ecology and Evolutionary Biology and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey
| | - Chris D Jiggins
- Department of Zoology, University of Cambridge, Cambridge, UK
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