DOCSLIB.ORG

Mutation Accumulation in Chromosomal Inversions Maintains Wing Pattern Polymorphism in a Butterfly

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Mutation Accumulation in Chromosomal Inversions Maintains Wing Pattern Polymorphism in a Butterfly bioRxiv preprint doi: https://doi.org/10.1101/736504; this version posted August 15, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Mutation accumulation in chromosomal inversions maintains wing pattern polymorphism in a butterfly Paul Jay1 *, Mathieu Chouteau1,2 *, Annabel Whibley3, Héloïse Bastide4, Violaine Llaurens4, Hugues Parrinello5, and Mathieu Joron1 1CEFE, CNRS, Université de Montpellier, Université Paul Valery, Montpellier 3, EPHE, IRD, Montpellier, France 2LEEISA, USR 63456, Université De Guyane, CNRS Guyane, IFREMER Guyane, 275 route de Montabo, 797334 Cayenne, French Guiana 3School of Biological Sciences, University of Auckland, Auckland, New Zealand 4ISYEB, UMR7205 CNRS-MNHN-9UPMC-EPHE, Muséum national d’Histoire naturelle, CP 50,45 rue Buffon, 75005 Paris, 10France. 5MGX, Biocampus Montpellier, CNRS, INSERM, Université Montpellier, Montpellier, France *These authors contributed equally. While natural selection favours the fittest genotype, polymor- The Amazonian butterfly Heliconius numata displays wing phisms are maintained over evolutionary timescales in numer- pattern polymorphism with up to seven morphs coexisting ous species. Why these long-lived polymorphisms are often as- within a single locality, each one engaged in warning color sociated with chromosomal rearrangements remains obscure. mimicry with distinct groups of toxic species. Adult morphs Combining genome assemblies, population genomic analyses, vary in mimicry protection against predators and in mating and fitness assays, we studied the factors maintaining multiple success via disassortative mate preferences (13, 16). Poly- mimetic morphs in the butterfly Heliconius numata. We show morphic inversions at the mimicry locus on chromosome that the polymorphism is maintained because three chromoso- mal inversions controlling wing patterns express a recessive mu- 15 (supergene P) form three distinct haplotypes (5). The tational load, which prevents their fixation despite their ecolog- standard, ancestral haplotype constitutes the class of reces- ical advantage. Since inversions suppress recombination and sive P alleles and is found, for example, in the widespread hamper genetic purging, their formation fostered the capture morph silvana. Two classes of derived haplotypes are known, and accumulation of deleterious variants. This suggests that both associated with a chromosomal inversion called P1 many complex polymorphisms, instead of representing adap- (∼400kb, 21 genes), each conferring increased protection tations to the existence of alternative ecological optima, could against predatory attacks via mimicry. The first derived hap- be maintained primarily because chromosomal rearrangements lotype, encoding the morph bicoloratus, carries P1 alone; the are prone to carrying recessive harmful mutations. second class of derived haplotypes carries P1 linked with ad- Heliconius | Polymorphism | Supergene | Degeneration | Inversion | Load ditional yet still uncharacterized rearrangements (called BP2 Correspondence: [email protected], [email protected], math- in (5)) and occurs in morphs which typically exhibit interme- [email protected] diate levels of dominance, such as tarapotensis and arcuella. Polymorphic complex traits, which implicate the coordina- Inversion polymorphism and supergene formation originated tion of multiple elements of phenotype, are often controlled via the introgression of P1 from the H. pardalinus lineage by special genetic architectures involving chromosomal rear- (17). The series of chromosomal rearrangements initiated by rangements. Examples include dimorphic social organization introgression allows us to unravel the stepwise process by in several ant species (1), coloration and behavioral polymor- which structural variation has become associated with direc- phisms in many birds and butterflies (2–6), dimorphic flower tional and balancing selection. morphology in plants (7), as well as the extreme cases pro- vided by sexual dimorphism encoded by the extensively re- Comparative analysis of de novo genome assemblies of 12 arranged sex chromosomes. Why these polymorphisms arise H. numata individuals revealed a history of supergene for- is a long-standing question in biology (8–12). mation characterized by the sequential accretion of three ad- The so-called supergenes controlling these striking polymor- jacent inversions with breakpoint reuse. Pairwise alignment phisms are characterized by the suppression of recombination of assemblies shows that all derived haplotypes belonging to between linked loci, often through polymorphic chromoso- the intermediate dominant allelic class display two newly- mal rearrangements which are thought to preserve alternative described inversions: P2 (200kb, 15 genes), adjacent to P1, combinations of co-adapted alleles (1,4,5, 7, 12). The en- and the longer P3 (1150 kb, 71 genes), adjacent to P2 (Fig coded phenotypes are often assumed to reflect the existence 1A, Sup. Fig. S1, Sup. Fig. S2). Sliding-window PCA of multiple, distinct adaptive optima, and are frequently as- along the supergene region confirmed the dominance of de- sociated with antagonistic ecological factors such as differ- rived arrangements (denoted Hn1 and Hn123) to the ances- ential survival or mating success (3, 13–15). Yet why and tral arrangement (denoted Hn0) and their prevalence across how alternative chromosomal forms become associated with all populations of the Amazon (Fig 1B, Fig 1C, Sup. Fig. S3, complex life-history variation and ecological trade-offs is not Sup. Fig. S4). Multiple genes in the inverted regions showed understood. significant differential expression compared to ancestral seg- Jay & Chouteau et al. | bioRχiv | August 15, 2019 | 1–8 bioRxiv preprint doi: https://doi.org/10.1101/736504; this version posted August 15, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Fig. 1. Genomic architecture of the H. numata wing pattern polymorphism A. Alignment of the genome assemblies from 4 H. numata morphs across the supergene region on chromosome 15. B. Sliding window Principal Component Analysis (PCA) computed along the supergene (non-overlapping 5kb windows). For clarity, only a subset of morphs are shown here (full dataset presented in Sup. Fig. S3). Each colored line represents the variation in the position of a specimen on the first PCA axis along chromosome 15 . Within the inversions, individual genomes are characterized by one of three genotypes : homozygous for the inversion (down), heterozygous (middle), homozygous for the standard arrangement (top). The gene annotation track is shown under the plot, with the forward strand in the lower panel and the reverse strand in the upper panel. Each gene is represented by a different colour C. Structure of the H. numata supergene P. Three chromosome types are found in H. numata populations, carrying the ancestral gene order (Hn0), inversion P1 (Hn1), or inversions P1,P2 and P3 (Hn123). D. Analysis of divergence times between Hn123 and Hn0 at inversions segment. The TMRCA between Hn123 and Hn0 and the most ancient common ancestor of Hn123 provide respectively the upper and lower bound of the inversions formation time. Boxplots display the distribution of estimated times computed on 5kb sliding window across the supergene (estimates plotted along the supergene presented in Sup. Fig. S7).Time intervals are consistent with the stepwise accretion of P1,P2 and P3, but the simultaneous origin of P2 and P3 cannot be formally rejected. ments, but this likely reflects divergence rather than direct Since chromosomal regions carrying inversions rarely form breakpoint effects (Sup. Fig. S5). Indeed, none of the break- chiasma during meiosis, recombination is strongly reduced points of P1,P2 or P3 fell within a gene, and no transcript among haplotypes with opposite orientations (18). Recombi- found in Hn0 specimens was missing, disrupted, or differen- nation suppression between structural alleles is predicted to tially spliced in specimens with inversions (Hn1 and Hn123). lead to inefficient purging of deleterious variants and there- fore to the accumulation of deleterious mutations and trans- In contrast to the introgressive origin of P1(Sup Fig. S6, posable elements (TEs) (19). Consistent with this predic- (17)), inversions P2 and P3 are younger and originated within the H. numata lineage. Upper and lower estimates of in- tion, estimation of the TE dynamics obtained by comput- version ages, obtained by determining the most recent co- ing whole genome TE divergence supports a recent burst alescence events between Hn0+Hn1 and Hn123, and within of TE insertion within the inversions, reported particularly Hn123, respectively, suggest that the P supergene has evolved by TEs belonging to the RC, DNA and LINE classes (Fig. 2A, Fig. 2B). Inverted haplotypes show a significant size in- in three steps, involving the introgression of P1followed by crease (mean=+9.47%) compared to their corresponding non- the successive occurrence of P2 and P3 between ca. 1.8 and 3.0 Mya (Fig. 1D, Sup. Fig. S7). Haplotypes show size- inverted region in Hn0 (Fig. 2C) and this expansion was able peaks of differentiation
Load more

Recommended publications
  • A Supergene-Linked Estrogen Receptor Drives Alternative Phenotypes in a Polymorphic Songbird
    A supergene-linked estrogen receptor drives alternative phenotypes in a polymorphic songbird Jennifer R. Merritta,1, Kathleen E. Grogana, Wendy M. Zinzow-Kramera, Dan Sunb, Eric A. Ortlundc, Soojin V. Yib, and Donna L. Maneya aDepartment of Psychology, Emory University, Atlanta, GA 30322; bSchool of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332; and cDepartment of Biochemistry, Emory University, Atlanta, GA 30322 Edited by Gene E. Robinson, University of Illinois at Urbana–Champaign, Urbana, IL, and approved July 8, 2020 (received for review June 3, 2020) Behavioral evolution relies on genetic changes, yet few behaviors tan-striped (TS) morph are homozygous for the standard ar- can be traced to specific genetic sequences in vertebrates. Here we rangement, ZAL2 (13, 14) (Fig. 1A). The rearrangement is provide experimental evidence showing that differentiation of a maintained in the population because of the species’ unique dis- single gene has contributed to the evolution of divergent behav- assortative mating system; nearly every breeding pair consists of ioral phenotypes in the white-throated sparrow, a common back- one individual of each morph (15). Because almost all WS birds yard songbird. In this species, a series of chromosomal inversions are heterozygous for ZAL2m (15, 16), this mating system keeps has formed a supergene that segregates with an aggressive phe- ZAL2m in a near-constant state of heterozygosity (Fig. 1B), pro- notype. The supergene has captured ESR1, the gene that encodes foundly suppressing recombination and causing it to differentiate estrogen receptor α (ERα); as a result, this gene is accumulating from ZAL2 (15, 17). changes that now distinguish the supergene allele from the stan- The rearranged region of ZAL2m in white-throated sparrows dard allele.
    [Show full text]
  • Stance As Nonself Initiates a Complex Cascade of Events Which
    JOURNAL OF SURGICAL RESEARCH 39, l72- 18 1 ( 1985) CURRENT RESEARCH REVIEW Major Histocompatibility Complex Regulation of the Immune Response DAVID H. GUTMANN, PH.D., AND JOHN E. NIEDERHUBER, M.D. Departments of Microbiology and Immunology and Surgery, The University of Michigan Medical School, Ann Arbor, Michigan 48109 Submitted for publication July 18, 1984 The ability of an organism to distinguish self from nonself is determined by a cluster of genes located in the major histocompatibility complex. Recent advances in molecular genetics and cellular immunology have begun to elucidate the mechanisms responsible for immune response regulation. In this review article, the genetic organization of the murine and human major histocompatibility complexes and the manner by which their gene products modulate immune responsiveness are discussed. 0 1985 Academic Press. Inc. INTRODUCTION ulate the immune response in several ways. Whether this regulation is their primary The body’s recognition of a foreign sub- function is not clear, as it seemspossible that stance as nonself initiates a complex cascade other as yet undiscovered levels of regulation of events which leads to an immune response. of the immune response may exist. Since Regulation of this immune response is con- much of our understanding of the role of the trolled by a cluster of tightly linked genes MHC in immune regulation has resulted encoded within the major histocompatibility from studies on the mouse MHC, the struc- complex (MHC) [ 1, 21. While the MHC was ture and function of both mouse and, when originally defined as the site for control of available, human MHC molecules will be graft rejection, it is now known that MHC discussed in this review.
    [Show full text]
  • Chromosomal Rearrangements Maintain a Polymorphic Supergene Controlling Butterfly Mimicry
    Published in which should be cited to refer to this work. Chromosomal rearrangements maintain a polymorphic supergene controlling butterfly mimicry Mathieu Joron1,2,3, Lise Frezal1*, Robert T. Jones4*, Nicola L. Chamberlain4, Siu F. Lee5, Christoph R. Haag6, Annabel Whibley1, Michel Becuwe2, Simon W. Baxter7, Laura Ferguson7, Paul A. Wilkinson4, Camilo Salazar8, Claire Davidson9, Richard Clark9, Michael A. Quail9, Helen Beasley9, Rebecca Glithero9, Christine Lloyd9, Sarah Sims9, Matthew C. Jones9, Jane Rogers9, Chris D. Jiggins7 & Richard H. ffrench-Constant4 Supergenes are tight clusters of loci that facilitate the co-segregation be tightly linked from the outset or whether the association between of adaptive variation, providing integrated control of complex elements can be acquired, either gradually or in a single mutational adaptive phenotypes1. Polymorphic supergenes, in which specific step7–10,16–19. Chromosomal rearrangements, which can bring genes into combinations of traits are maintained within a single population, closer physical association and influence local recombination, offer one were first described for ‘pin’ and ‘thrum’ floral types in Primula1 and route through which supergenes may be assembled from more loosely Fagopyrum2, but classic examples are also found in insect mimicry3–5 linked components7,8,17–19. Although there are many cases of poly- and snail morphology6. Understanding the evolutionary mechan- morphic inversions associated with adaptive variation12,20, variation is isms that generate these co-adapted gene sets, as well as the mode in most cases geographical, rather than being maintained within popula- of limiting the production of unfit recombinant forms, remains a tions, and effects on local adaptation are cumulative. In contrast, super- substantial challenge7–10.
    [Show full text]
  • Supergene Evolution Triggered by the Introgression of a Chromosomal Inversion
    Report Supergene Evolution Triggered by the Introgression of a Chromosomal Inversion Graphical Abstract Authors Paul Jay, Annabel Whibley, Lise Frezal, ..., James Mallet, Kanchon K. Dasmahapatra, Mathieu Joron Correspondence [email protected] (P.J.), [email protected] (M.J.) In Brief Supergenes are genetic architectures underlying complex polymorphisms in many organisms. Jay et al. show that a supergene controlling mimicry polymorphism in a butterfly was formed by the introgression of a chromosomal inversion from another species. Their results emphasize the role of hybridization in the evolution of novel genetic architectures. Highlights d Chromosomal inversions underlie wing-pattern polymorphism in a Heliconius butterfly d Inversion was introgressed from another species, then maintained as a polymorphism d 1.3 Ma of evolution in separate taxa explains the divergence of supergene haplotypes d Introgression may play a key role in the formation of novel genetic architectures Jay et al., 2018, Current Biology 28, 1–7 June 4, 2018 ª 2018 Elsevier Ltd. https://doi.org/10.1016/j.cub.2018.04.072 Please cite this article in press as: Jay et al., Supergene Evolution Triggered by the Introgression of a Chromosomal Inversion, Current Biology (2018), https://doi.org/10.1016/j.cub.2018.04.072 Current Biology Report Supergene Evolution Triggered by the Introgression of a Chromosomal Inversion Paul Jay,1,* Annabel Whibley,2 Lise Frezal, 3 Marı´aA´ ngeles Rodrı´guez de Cara,1 Reuben W. Nowell,4 James Mallet,5 Kanchon K. Dasmahapatra,6 and
    [Show full text]
  • A Behavioral Polymorphism Caused by a Single Gene Inside a Supergene
    bioRxiv preprint doi: https://doi.org/10.1101/2020.01.13.897637; this version posted January 16, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC 4.0 International license. Merritt et al., 13 JAN 2020 – preprint copy – bioRxiv A behavioral polymorphism caused by a single gene inside a supergene Jennifer R. Merritta,1, Kathleen E. Grogana, Wendy M. Zinzow-Kramera, Dan Sunb, Eric A. Ortlundc, Soojin V. Yib, Donna L. Maneya a Department of Psychology, Emory University, Atlanta, GA 30322 b School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332 c Department of Biochemistry, Emory University, Atlanta, GA 30322 1 Correspondence: [email protected] Abstract Behavioral evolution relies on genetic changes, yet few social behaviors can be traced to specific genetic seQuences in vertebrates. Here, we show experimental evidence that differentiation of a single gene has contributed to divergent behavioral phenotypes in the white-throated sparrow, a common North American songbird. In this species, one of two alleles of ESR1, encoding estrogen receptor a (ERa), has been captured inside a differentiating supergene that segregates with an aggressive phenotype, such that ESR1 expression predicts aggression. Here, we show that the aggressive phenotype associated with the supergene is prevented by ESR1 knockdown in a single brain region. Next, we show that in a free-living population, aggression is predicted by allelic imbalance favoring the supergene allele. Cis-regulatory variation between the two alleles affects transcription factor binding sites, DNA methylation, and rates of transcription.
    [Show full text]
  • Multiple Convergent Supergene Evolution Events in Mating-Type
    Multiple convergent supergene evolution events in mating-type chromosomes Sara Branco, Fantin Carpentier, Ricardo Rodriguez de la Vega, Hélène Badouin, Alodie Snirc, Stéphanie Le Prieur, Marco Coelho, Damien de Vienne, Fanny Hartmann, Dominik Begerow, et al. To cite this version: Sara Branco, Fantin Carpentier, Ricardo Rodriguez de la Vega, Hélène Badouin, Alodie Snirc, et al.. Multiple convergent supergene evolution events in mating-type chromosomes. Nature Communica- tions, Nature Publishing Group, 2018, 9 (1), pp.2000. 10.1038/s41467-018-04380-9. hal-01796609 HAL Id: hal-01796609 https://hal.archives-ouvertes.fr/hal-01796609 Submitted on 21 May 2018 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. ARTICLE DOI: 10.1038/s41467-018-04380-9 OPEN Multiple convergent supergene evolution events in mating-type chromosomes Sara Branco1,2, Fantin Carpentier1, Ricardo C. Rodríguez de la Vega 1, Hélène Badouin1,3, Alodie Snirc1, Stéphanie Le Prieur1, Marco A. Coelho4, Damien M. de Vienne3, Fanny E. Hartmann1, Dominik Begerow5, Michael E. Hood6 & Tatiana Giraud 1 Convergent adaptation provides unique insights into the predictability of evolution and ulti- 1234567890():,; mately into processes of biological diversification. Supergenes (beneficial gene linkage) are striking examples of adaptation, but little is known about their prevalence or evolution.
    [Show full text]
  • Simple Inheritance, Complex Regulation: Supergene‐Mediated
    Received: 15 January 2020 | Revised: 3 July 2020 | Accepted: 18 July 2020 DOI: 10.1111/mec.15581 ORIGINAL ARTICLE Simple inheritance, complex regulation: Supergene-mediated fire ant queen polymorphism Samuel V. Arsenault1 | Joanie T. King1,2 | Sasha Kay1 | Kip D. Lacy1,3 | Kenneth G. Ross1 | Brendan G. Hunt1 1Department of Entomology, University of Georgia, Athens, GA, USA Abstract 2Department of Entomology, Texas A&M The fire ant Solenopsis invicta exists in two alternate social forms: monogyne nests University, College Station, TX, USA contain a single reproductive queen and polygyne nests contain multiple reproduc- 3Laboratory of Social Evolution and Behavior, The Rockefeller University, New tive queens. This colony-level social polymorphism corresponds with individual dif- York, NY, USA ferences in queen physiology, queen dispersal patterns and worker discrimination Correspondence behaviours, all evidently regulated by an inversion-based supergene that spans more Samuel V. Arsenault, Kenneth G. Ross, than 13 Mb of a “social chromosome,” contains over 400 protein-coding genes and and Brendan G. Hunt, Department of Entomology, University of Georgia, Athens, rarely undergoes recombination. The specific mechanisms by which this supergene GA, USA. influences expression of the many distinctive features that characterize the alternate Email: [email protected]; [email protected]; [email protected] forms remain almost wholly unknown. To advance our understanding of these mech- anisms, we explore the effects of social chromosome genotype and natal colony so- Funding information Division of Integrative Organismal Systems, cial form on gene expression in queens sampled as they embarked on nuptial flights, Grant/Award Number: 1755130; Division using RNA-sequencing of brains and ovaries.
    [Show full text]
  • Avian Supergenes
    PERSPECTIVES EVOLUTION important role in generating biological diver- Lekking ruffs. From left to right, a female, an sity in taxa ranging from plants to humans. independent male, and a satellite male ruff. A third The mimetic wing patterns of butterflies are type of male ruff closely resembles the female. Recent Avian a particularly well-documented example of research has shed light on the genetic underpinnings of how supergenes can underlie complex ad- the ruff’s complex reproductive strategies (1, 2). aptations (4). However, knowledge of the supergenes genetic architecture of supergenes remains attraction and attempt to “steal” copula- limited, and the molecular mechanisms by tions. Faeder males (<1%) mimic females Genetic data reveal how which they can generate complex pheno- in their plumage and smaller size and also two complex bird mating types are unclear. The recent studies of the steal copulations. ruff (1, 2) and the white-throated sparrow (3) As Küpper et al. (1) and Lamichhaney et systems evolved provide critical advances to our understand- al. (2) now show, these three reproductive ing of these aspects of supergenes. behaviors and associated phenotypes are de- By Scott Taylor 1,2 and Leonardo Campagna1,2 Reduced recombination within super- termined by a ~4.5 Mb inversion located on genes is central to their evolution, allowing an autosome (see the figure). Independent s the extravagant displays of birds of multiple genes to be inherited as a single males carry two copies of the ancestral, non- paradise remind us, many birds go to linked unit and setting the stage for their inverted chromosome: They do not possess great lengths to pass their genes on coevolution.
    [Show full text]
  • Unravelling the Genes Forming the Wing Pattern Supergene in the Polymorphic Butterfy Heliconius Numata Suzanne V
    Saenko et al. EvoDevo (2019) 10:16 https://doi.org/10.1186/s13227-019-0129-2 EvoDevo RESEARCH Open Access Unravelling the genes forming the wing pattern supergene in the polymorphic butterfy Heliconius numata Suzanne V. Saenko1†, Mathieu Chouteau2†, Florence Piron‑Prunier1, Corinne Blugeon3, Mathieu Joron4 and Violaine Llaurens1* Abstract Background: Unravelling the genetic basis of polymorphic characters is central to our understanding of the ori‑ gins and diversifcation of living organisms. Recently, supergenes have been implicated in a wide range of complex polymorphisms, from adaptive colouration in butterfies and fsh to reproductive strategies in birds and plants. The concept of a supergene is now a hot topic in biology, and identifcation of its functional elements is needed to shed light on the evolution of highly divergent adaptive traits. Here, we apply diferent gene expression analyses to study the supergene P that controls polymorphism of mimetic wing colour patterns in the neotropical butterfy Heliconius numata. Results: We performed de novo transcriptome assembly and diferential expression analyses using high‑throughput Illumina RNA sequencing on developing wing discs of diferent H. numata morphs. Within the P interval, 30 and 17 of the 191 transcripts were expressed diferentially in prepupae and day‑1 pupae, respectively. Among these is the gene cortex, known to play a role in wing pattern formation in Heliconius and other Lepidoptera. Our in situ hybridization experiments confrmed the relationship between cortex expression and adult wing patterns. Conclusions: This study found the majority of genes in the P interval to be expressed in the developing wing discs during the critical stages of colour pattern formation, and detect drastic changes in expression patterns in multiple genes associated with structural variants.
    [Show full text]
  • The Chicken Major Histocompatibility Complex and Disease
    Animal Science Publications Animal Science 1998 The chicken major histocompatibility complex and disease Susan J. Lamont Iowa State University, [email protected] Follow this and additional works at: https://lib.dr.iastate.edu/ans_pubs Part of the Agriculture Commons, Animal Sciences Commons, Genetics Commons, and the Immunology and Infectious Disease Commons The complete bibliographic information for this item can be found at https://lib.dr.iastate.edu/ ans_pubs/855. For information on how to cite this item, please visit http://lib.dr.iastate.edu/ howtocite.html. This Article is brought to you for free and open access by the Animal Science at Iowa State University Digital Repository. It has been accepted for inclusion in Animal Science Publications by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. The chicken major histocompatibility complex and disease Abstract The chicken major histocompatibility complex (MHC), or B complex, consists of several clusters of highly polymorphic genes, some of which are associated with disease resistance. The class I and class II antigens resemble their mammalian counterparts in the encoded protein structure. The class IV region encodes the B blood group antigens, which are readily identified yb serological blood-typing. The class III region appears to be divided in chickens, with some elements that are MHC-linked and others that map elsewhere. In addition the Rfp-Y system, which bears a strong similarity to the MHC, maps to the opposite side of the nucleolar organiser region on the same microchromosome as the MHC. Each class of MHC genes is a potential candidate for a role in disease resistance.
    [Show full text]
  • A Supergene-Linked Estrogen Receptor Drives Alternative Phenotypes in a Polymorphic Songbird
    A supergene-linked estrogen receptor drives alternative phenotypes in a polymorphic songbird Jennifer R. Merritta,1, Kathleen E. Grogana, Wendy M. Zinzow-Kramera, Dan Sunb, Eric A. Ortlundc, Soojin V. Yib, and Donna L. Maneya aDepartment of Psychology, Emory University, Atlanta, GA 30322; bSchool of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332; and cDepartment of Biochemistry, Emory University, Atlanta, GA 30322 Edited by Gene E. Robinson, University of Illinois at Urbana–Champaign, Urbana, IL, and approved July 8, 2020 (received for review June 3, 2020) Behavioral evolution relies on genetic changes, yet few behaviors tan-striped (TS) morph are homozygous for the standard ar- can be traced to specific genetic sequences in vertebrates. Here we rangement, ZAL2 (13, 14) (Fig. 1A). The rearrangement is provide experimental evidence showing that differentiation of a maintained in the population because of the species’ unique dis- single gene has contributed to the evolution of divergent behav- assortative mating system; nearly every breeding pair consists of ioral phenotypes in the white-throated sparrow, a common back- one individual of each morph (15). Because almost all WS birds yard songbird. In this species, a series of chromosomal inversions are heterozygous for ZAL2m (15, 16), this mating system keeps has formed a supergene that segregates with an aggressive phe- ZAL2m in a near-constant state of heterozygosity (Fig. 1B), pro- notype. The supergene has captured ESR1, the gene that encodes foundly suppressing recombination and causing it to differentiate estrogen receptor α (ERα); as a result, this gene is accumulating from ZAL2 (15, 17). changes that now distinguish the supergene allele from the stan- The rearranged region of ZAL2m in white-throated sparrows dard allele.
    [Show full text]
  • Gametophytic Self-Incompatibility Re-Examined: a Reply
    Heredity 54(1985) 131—138 TheGeneticalSociety ofGreat Britain Received 19 December 1983 Gametophytic self-incompatibility re-examined: a reply M. J. Lawrence, D. F. Marshall, Department of Genetics, University of Birmingham, V. E. Curtis and C. H. Fearon Birmingham B15 21T. In principle, as has long been known, there are two ways by which the stigmas or styles of the flowers of self- incompatible species could discriminate between incompatible and compatible pollen, for either the growth of the former would be inhibited (the oppositional hypothesis) or that of the latter stimulated (the complementary hypothesis). In practice, however, the genetics of gametophytic systems all but rules out the second possibility, largely because of the number of alleles involved. Furthermore, nearly all of the more recent evidence concerning the behaviour of pollen on the stigma or style, both of the observational and the biochemical kind, is inconsistent with the complementary hypothesis. In a recent paper, however, Mulcahy and Mulcahy (1983) have argued that the oppositional hypothesis is unable to provide a satisfactory explanation of several more recent observations concerning gametophytic systems and have proposed a new, multigenic model that is based on the complementary hypothesis of discrimination. A review of the evidence regarded by the Mulcahys as inconsistent with the oppositional hypothesis reveals that this is either not relevant to the question of discrimination or has been misunderstood. Furthermore, the Mulcahys' model is inconsistent with the empirical evidence concerning multi-locus systems and is formally consistent with one-locus systems only if it is assumed that the constituent loci of the S-supergene are very tightly or completely linked, an assumption not made by the Mulcahys.
    [Show full text]