1
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Kronforst MR, Sheikh SI. New molecular insights into butterfly pigmentation. Cell Rep 2023; 42:112981. [PMID: 37594895 DOI: 10.1016/j.celrep.2023.112981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 07/28/2023] [Accepted: 07/31/2023] [Indexed: 08/20/2023] Open
Abstract
Hanly et al.1 and Nishida et al.2 use distinct approaches to provide exceptional lessons regarding the genetic, molecular, morphological, and biochemical bases of butterfly wing pigmentation. These mechanistic insights collectively have important implications for our understanding of phenotype evolution.
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Affiliation(s)
- Marcus R Kronforst
- Department of Ecology & Evolution, The University of Chicago, Chicago, IL 60637, USA.
| | - Sofia I Sheikh
- Department of Ecology & Evolution, The University of Chicago, Chicago, IL 60637, USA
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2
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Bayala EX, VanKuren N, Massardo D, Kronforst MR. aristaless1 has a dual role in appendage formation and wing color specification during butterfly development. BMC Biol 2023; 21:100. [PMID: 37143075 PMCID: PMC10161628 DOI: 10.1186/s12915-023-01601-6] [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: 10/20/2022] [Accepted: 04/13/2023] [Indexed: 05/06/2023] Open
Abstract
BACKGROUND Highly diverse butterfly wing patterns have emerged as a powerful system for understanding the genetic basis of phenotypic variation. While the genetic basis of this pattern variation is being clarified, the precise developmental pathways linking genotype to phenotype are not well understood. The gene aristaless, which plays a role in appendage patterning and extension, has been duplicated in Lepidoptera. One copy, aristaless1, has been shown to control a white/yellow color switch in the butterfly Heliconius cydno, suggesting a novel function associated with color patterning and pigmentation. Here we investigate the developmental basis of al1 in embryos, larvae, and pupae using new antibodies, CRISPR/Cas9, RNAi, qPCR assays of downstream targets, and pharmacological manipulation of an upstream activator. RESULTS We find that Al1 is expressed at the distal tips of developing embryonic appendages consistent with its ancestral role. In developing wings, we observe Al1 accumulation within developing scale cells of white H. cydno during early pupation while yellow scale cells exhibit little Al1 at this time point. Reduced Al1 expression is also associated with yellow scale development in al1 knockouts and knockdowns. We propose that Al1 expression in future white scales might be related to an observed downregulation of the enzyme Cinnabar and other genes that synthesize and transport the yellow pigment, 3-hydroxykynurenine (3-OHK). Finally, we provide evidence that Al1 activation is under the control of Wnt signaling. CONCLUSIONS We propose a model in which high levels of Al1 during early pupation, which are mediated by Wnt, are important for melanic pigmentation and specifying white portions of the wing while reduced levels of Al1 during early pupation promote upregulation of proteins needed to move and synthesize 3-OHK, promoting yellow pigmentation. In addition, we discuss how the ancestral role of aristaless in appendage extension may be relevant in understanding the cellular mechanism behind color patterning in the context of the heterochrony hypothesis.
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Affiliation(s)
- Erick X Bayala
- Department of Ecology & Evolution, University of Chicago, Chicago, IL, 60637, USA.
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, 60637, USA.
| | - Nicholas VanKuren
- Department of Ecology & Evolution, University of Chicago, Chicago, IL, 60637, USA
| | - Darli Massardo
- Department of Ecology & Evolution, University of Chicago, Chicago, IL, 60637, USA
| | - Marcus R Kronforst
- Department of Ecology & Evolution, University of Chicago, Chicago, IL, 60637, USA
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, 60637, USA
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3
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Hill RI. Convergent flight morphology among Müllerian mimic mutualists. Evolution 2021; 75:2460-2479. [PMID: 34431522 DOI: 10.1111/evo.14331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 07/15/2021] [Accepted: 07/26/2021] [Indexed: 10/20/2022]
Abstract
Müllerian mimicry involves a signal mutualism between prey species, shaped by visually hunting predators, and recent work has emphasized the importance of color pattern. Predators respond to more than color pattern, however, and other traits are much less studied. This article examines the hypothesis of convergent evolution in flight-related morphology among eight mimicry complexes composed of 51 butterfly species (Nymphalidae, Danainae, Ithomiini) from a single community in Ecuador. Phylogenetic comparative analyses of 14 variables indicated strong morphological differences between mimicry complexes belonging to three clusters of morphological space ("large yellow transparent," "tiger," and "transparent"), not the eight predicted based on color pattern alone. Analyses found convergence within mimicry complexes, convergence between mimicry complexes within morphospace clusters, and divergence between mimicry complexes from different morphospace clusters. These three clusters differed in size, and body and wing shape, predicting that flight biomechanics also converge (i.e., locomotor mimicry). Potential constraints on evolution of morphological mimicry related to predator discrimination, and evolutionary rates, likely e xplain why flight-related morphology differences were limited to three clusters of morphological space. Finally, the added complexity that flight-related morphology brings to signals between predator and prey indicates that evolutionary switches in color pattern are not all equally likely, potentially limiting the evolution of color patterns if they do not match morphology.
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Affiliation(s)
- Ryan I Hill
- Department of Integrative Biology, University of California, Berkeley, Berkeley, California, 94720.,Current Address: Department of Biological Sciences, University of the Pacific, Stockton, California, 95211
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4
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Andrade P, Carneiro M. Pterin-based pigmentation in animals. Biol Lett 2021; 17:20210221. [PMID: 34403644 PMCID: PMC8370806 DOI: 10.1098/rsbl.2021.0221] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 07/26/2021] [Indexed: 12/19/2022] Open
Abstract
Pterins are one of the major sources of bright coloration in animals. They are produced endogenously, participate in vital physiological processes and serve a variety of signalling functions. Despite their ubiquity in nature, pterin-based pigmentation has received little attention when compared to other major pigment classes. Here, we summarize major aspects relating to pterin pigmentation in animals, from its long history of research to recent genomic studies on the molecular mechanisms underlying its evolution. We argue that pterins have intermediate characteristics (endogenously produced, typically bright) between two well-studied pigment types, melanins (endogenously produced, typically cryptic) and carotenoids (dietary uptake, typically bright), providing unique opportunities to address general questions about the biology of coloration, from the mechanisms that determine how different types of pigmentation evolve to discussions on honest signalling hypotheses. Crucial gaps persist in our knowledge on the molecular basis underlying the production and deposition of pterins. We thus highlight the need for functional studies on systems amenable for laboratory manipulation, but also on systems that exhibit natural variation in pterin pigmentation. The wealth of potential model species, coupled with recent technological and analytical advances, make this a promising time to advance research on pterin-based pigmentation in animals.
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Affiliation(s)
- Pedro Andrade
- CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
| | - Miguel Carneiro
- CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
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5
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Ruttenberg DM, VanKuren NW, Nallu S, Yen SH, Peggie D, Lohman DJ, Kronforst MR. The evolution and genetics of sexually dimorphic 'dual' mimicry in the butterfly Elymnias hypermnestra. Proc Biol Sci 2021; 288:20202192. [PMID: 33434461 DOI: 10.1098/rspb.2020.2192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Sexual dimorphism is a major component of morphological variation across the tree of life, but the mechanisms underlying phenotypic differences between sexes of a single species are poorly understood. We examined the population genomics and biogeography of the common palmfly Elymnias hypermnestra, a dual mimic in which female wing colour patterns are either dark brown (melanic) or bright orange, mimicking toxic Euploea and Danaus species, respectively. As males always have a melanic wing colour pattern, this makes E. hypermnestra a fascinating model organism in which populations vary in sexual dimorphism. Population structure analysis revealed that there were three genetically distinct E. hypermnestra populations, which we further validated by creating a phylogenomic species tree and inferring historical barriers to gene flow. This species tree demonstrated that multiple lineages with orange females do not form a monophyletic group, and the same is true of clades with melanic females. We identified two single nucleotide polymorphisms (SNPs) near the colour patterning gene WntA that were significantly associated with the female colour pattern polymorphism, suggesting that this gene affects sexual dimorphism. Given WntA's role in colour patterning across Nymphalidae, E. hypermnestra females demonstrate the repeatability of the evolution of sexual dimorphism.
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Affiliation(s)
- Dee M Ruttenberg
- Department of Ecology and Evolution, The University of Chicago, Chicago, IL 60637, USA
| | - Nicholas W VanKuren
- Department of Ecology and Evolution, The University of Chicago, Chicago, IL 60637, USA
| | - Sumitha Nallu
- Department of Ecology and Evolution, The University of Chicago, Chicago, IL 60637, USA
| | - Shen-Horn Yen
- Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan
| | - Djunijanti Peggie
- Museum Zoologicum Bogoriense, Research Center for Biology, Indonesian Institute of Sciences (LIPI), Cibinong-Bogor 16911, Indonesia
| | - David J Lohman
- Biology Department, City College of New York, City University of New York, New York, NY 10031, USA.,PhD Program in Biology, Graduate Center, City University of New York, New York, NY 10016, USA.,Entomology Section, National Museum of Natural History, Manila 1000, Philippines
| | - Marcus R Kronforst
- Department of Ecology and Evolution, The University of Chicago, Chicago, IL 60637, USA
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6
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Deshmukh R, Lakhe D, Kunte K. Tissue-specific developmental regulation and isoform usage underlie the role of doublesex in sex differentiation and mimicry in Papilio swallowtails. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200792. [PMID: 33047041 PMCID: PMC7540742 DOI: 10.1098/rsos.200792] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 09/08/2020] [Indexed: 06/11/2023]
Abstract
Adaptive phenotypes often arise by rewiring existing developmental networks. Co-option of transcription factors in novel contexts has facilitated the evolution of ecologically important adaptations. doublesex (dsx) governs fundamental sex differentiation during embryonic stages and has been co-opted to regulate diverse secondary sexual dimorphisms during pupal development of holometabolous insects. In Papilio polytes, dsx regulates female-limited mimetic polymorphism, resulting in mimetic and non-mimetic forms. To understand how a critical gene such as dsx regulates novel wing patterns while maintaining its basic function in sex differentiation, we traced its expression through metamorphosis in P. polytes using developmental transcriptome data. We found three key dsx expression peaks: (i) eggs in pre- and post-ovisposition stages; (ii) developing wing discs and body in final larval instar; and (iii) 3-day pupae. We identified potential dsx targets using co-expression and differential expression analysis, and found distinct, non-overlapping sets of genes-containing putative dsx-binding sites-in developing wings versus abdominal tissue and in mimetic versus non-mimetic individuals. This suggests that dsx regulates distinct downstream targets in different tissues and wing colour morphs and has perhaps acquired new, previously unknown targets, for regulating mimetic polymorphism. Additionally, we observed that the three female isoforms of dsx were differentially expressed across stages (from eggs to adults) and tissues and differed in their protein structure. This may promote differential protein-protein interactions for each isoform and facilitate sub-functionalization of dsx activity across its isoforms. Our findings suggest that dsx employs tissue-specific downstream effectors and partitions its functions across multiple isoforms to regulate primary and secondary sexual dimorphism through insect development.
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7
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Kuwalekar M, Deshmukh R, Padvi A, Kunte K. Molecular Evolution and Developmental Expression of Melanin Pathway Genes in Lepidoptera. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00226] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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8
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VanKuren NW, Massardo D, Nallu S, Kronforst MR. Butterfly Mimicry Polymorphisms Highlight Phylogenetic Limits of Gene Reuse in the Evolution of Diverse Adaptations. Mol Biol Evol 2020; 36:2842-2853. [PMID: 31504750 DOI: 10.1093/molbev/msz194] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Some genes have repeatedly been found to control diverse adaptations in a wide variety of organisms. Such gene reuse reveals not only the diversity of phenotypes these unique genes control but also the composition of developmental gene networks and the genetic routes available to and taken by organisms during adaptation. However, the causes of gene reuse remain unclear. A small number of large-effect Mendelian loci control a huge diversity of mimetic butterfly wing color patterns, but reasons for their reuse are difficult to identify because the genetic basis of mimicry has primarily been studied in two systems with correlated factors: female-limited Batesian mimicry in Papilio swallowtails (Papilionidae) and non-sex-limited Müllerian mimicry in Heliconius longwings (Nymphalidae). Here, we break the correlation between phylogenetic relationship and sex-limited mimicry by identifying loci controlling female-limited mimicry polymorphism Hypolimnas misippus (Nymphalidae) and non-sex-limited mimicry polymorphism in Papilio clytia (Papilionidae). The Papilio clytia polymorphism is controlled by the genome region containing the gene cortex, the classic P supergene in Heliconius numata, and loci controlling color pattern variation across Lepidoptera. In contrast, female-limited mimicry polymorphism in Hypolimnas misippus is associated with a locus not previously implicated in color patterning. Thus, although many species repeatedly converged on cortex and its neighboring genes over 120 My of evolution of diverse color patterns, female-limited mimicry polymorphisms each evolved using a different gene. Our results support conclusions that gene reuse occurs mainly within ∼10 My and highlight the puzzling diversity of genes controlling seemingly complex female-limited mimicry polymorphisms.
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Affiliation(s)
| | - Darli Massardo
- Department of Ecology & Evolution, The University of Chicago, Chicago, IL
| | - Sumitha Nallu
- Department of Ecology & Evolution, The University of Chicago, Chicago, IL
| | - Marcus R Kronforst
- Department of Ecology & Evolution, The University of Chicago, Chicago, IL
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9
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Baral S, Arumugam G, Deshmukh R, Kunte K. Genetic architecture and sex-specific selection govern modular, male-biased evolution of doublesex. SCIENCE ADVANCES 2019; 5:eaau3753. [PMID: 31086812 PMCID: PMC6506240 DOI: 10.1126/sciadv.aau3753] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 03/29/2019] [Indexed: 06/09/2023]
Abstract
doublesex regulates early embryonic sex differentiation in holometabolous insects, along with the development of species-, sex-, and morph-specific adaptations during pupal stages. How does a highly conserved gene with a critical developmental role also remain functionally dynamic enough to gain ecologically important adaptations that are divergent in sister species? We analyzed patterns of exon-level molecular evolution and protein structural homology of doublesex from 145 species of four insect orders representing 350 million years of divergence. This analysis revealed that evolution of doublesex was governed by a modular architecture: Functional domains and female-specific regions were highly conserved, whereas male-specific sequences and protein structures evolved up to thousand-fold faster, with sites under pervasive and/or episodic positive selection. This pattern of sex bias was reversed in Hymenoptera. Thus, highly conserved yet dynamic master regulators such as doublesex may partition specific conserved and novel functions in different genic modules at deep evolutionary time scales.
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10
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Andrade P, Pinho C, Pérez I de Lanuza G, Afonso S, Brejcha J, Rubin CJ, Wallerman O, Pereira P, Sabatino SJ, Bellati A, Pellitteri-Rosa D, Bosakova Z, Bunikis I, Carretero MA, Feiner N, Marsik P, Paupério F, Salvi D, Soler L, While GM, Uller T, Font E, Andersson L, Carneiro M. Regulatory changes in pterin and carotenoid genes underlie balanced color polymorphisms in the wall lizard. Proc Natl Acad Sci U S A 2019; 116:5633-5642. [PMID: 30819892 DOI: 10.1101/481895] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023] Open
Abstract
Reptiles use pterin and carotenoid pigments to produce yellow, orange, and red colors. These conspicuous colors serve a diversity of signaling functions, but their molecular basis remains unresolved. Here, we show that the genomes of sympatric color morphs of the European common wall lizard (Podarcis muralis), which differ in orange and yellow pigmentation and in their ecology and behavior, are virtually undifferentiated. Genetic differences are restricted to two small regulatory regions near genes associated with pterin [sepiapterin reductase (SPR)] and carotenoid [beta-carotene oxygenase 2 (BCO2)] metabolism, demonstrating that a core gene in the housekeeping pathway of pterin biosynthesis has been coopted for bright coloration in reptiles and indicating that these loci exert pleiotropic effects on other aspects of physiology. Pigmentation differences are explained by extremely divergent alleles, and haplotype analysis revealed abundant transspecific allele sharing with other lacertids exhibiting color polymorphisms. The evolution of these conspicuous color ornaments is the result of ancient genetic variation and cross-species hybridization.
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Affiliation(s)
- Pedro Andrade
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal
| | - Catarina Pinho
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal
| | - Guillem Pérez I de Lanuza
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal
| | - Sandra Afonso
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal
| | - Jindřich Brejcha
- Department of Philosophy and History of Science, Faculty of Science, Charles University, 128 00 Prague 2, Czech Republic
- Department of Zoology, National Museum, 193 00 Prague, Czech Republic
- Ethology Laboratory, Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, 469 80 Paterna, Spain
| | - Carl-Johan Rubin
- Science for Life Laboratory Uppsala, Department of Medical Biochemistry and Microbiology, Uppsala University, 752 36 Uppsala, Sweden
| | - Ola Wallerman
- Science for Life Laboratory Uppsala, Department of Medical Biochemistry and Microbiology, Uppsala University, 752 36 Uppsala, Sweden
| | - Paulo Pereira
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal
| | - Stephen J Sabatino
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal
| | - Adriana Bellati
- Department of Earth and Environmental Sciences, University of Pavia, 27100 Pavia, Italy
| | | | - Zuzana Bosakova
- Department of Analytical Chemistry, Faculty of Science, Charles University, 128 43 Prague 2, Czech Republic
| | - Ignas Bunikis
- Science for Life Laboratory Uppsala, Department of Immunology, Genetics and Pathology, Uppsala University, 752 36 Uppsala, Sweden
| | - Miguel A Carretero
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal
| | | | - Petr Marsik
- Department of Food Science, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, 165 21 Prague 6, Czech Republic
| | - Francisco Paupério
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal
| | - Daniele Salvi
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal
- Department of Health, Life and Environmental Sciences, University of L'Aquila, 67100 L'Aquila, Italy
| | - Lucile Soler
- Science for Life Laboratory, National Bioinformatics Infrastructure Sweden (NBIS), 751 23 Uppsala, Sweden
| | - Geoffrey M While
- School of Biological Sciences, University of Tasmania, Hobart, TAS 7005 Tasmania, Australia
- Department of Zoology, University of Oxford, OX1 3PS Oxford, United Kingdom
| | - Tobias Uller
- Department of Biology, Lund University, 223 62 Lund, Sweden
| | - Enrique Font
- Ethology Laboratory, Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, 469 80 Paterna, Spain
| | - Leif Andersson
- Science for Life Laboratory Uppsala, Department of Medical Biochemistry and Microbiology, Uppsala University, 752 36 Uppsala, Sweden;
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843
| | - Miguel Carneiro
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, 4485-661 Vairão, Portugal;
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal
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11
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Regulatory changes in pterin and carotenoid genes underlie balanced color polymorphisms in the wall lizard. Proc Natl Acad Sci U S A 2019; 116:5633-5642. [PMID: 30819892 PMCID: PMC6431182 DOI: 10.1073/pnas.1820320116] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Reptiles show an amazing color diversity based on variation in melanins, carotenoids, and pterins. This study reveals genes controlling differences between three color morphs (white, orange, and yellow) in the common wall lizard. Orange pigmentation, due to high levels of orange/red pterins in skin, is caused by genetic changes in the sepiapterin reductase gene. Yellow skin, showing high levels of yellow carotenoids, is controlled by the beta-carotene oxygenase 2 locus. Thus, the color polymorphism in the common wall lizard is associated with changes in two small regions of the genome containing genes with crucial roles in pterin and carotenoid metabolism. These genes are likely to have pleiotropic effects on behavior and other traits associated with the different color morphs. Reptiles use pterin and carotenoid pigments to produce yellow, orange, and red colors. These conspicuous colors serve a diversity of signaling functions, but their molecular basis remains unresolved. Here, we show that the genomes of sympatric color morphs of the European common wall lizard (Podarcis muralis), which differ in orange and yellow pigmentation and in their ecology and behavior, are virtually undifferentiated. Genetic differences are restricted to two small regulatory regions near genes associated with pterin [sepiapterin reductase (SPR)] and carotenoid [beta-carotene oxygenase 2 (BCO2)] metabolism, demonstrating that a core gene in the housekeeping pathway of pterin biosynthesis has been coopted for bright coloration in reptiles and indicating that these loci exert pleiotropic effects on other aspects of physiology. Pigmentation differences are explained by extremely divergent alleles, and haplotype analysis revealed abundant transspecific allele sharing with other lacertids exhibiting color polymorphisms. The evolution of these conspicuous color ornaments is the result of ancient genetic variation and cross-species hybridization.
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