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Schmid S, Bachmann Salvy M, Garcia Jimenez A, Bertrand JAM, Cortesi F, Heim S, Huyghe F, Litsios G, Marcionetti A, O'Donnell JL, Riginos C, Tettamanti V, Salamin N. Gene flow throughout the evolutionary history of a colour polymorphic and generalist clownfish. Mol Ecol 2024; 33:e17436. [PMID: 38872589 DOI: 10.1111/mec.17436] [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: 11/07/2023] [Revised: 05/12/2024] [Accepted: 05/17/2024] [Indexed: 06/15/2024]
Abstract
Even seemingly homogeneous on the surface, the oceans display high environmental heterogeneity across space and time. Indeed, different soft barriers structure the marine environment, which offers an appealing opportunity to study various evolutionary processes such as population differentiation and speciation. Here, we focus on Amphiprion clarkii (Actinopterygii; Perciformes), the most widespread of clownfishes that exhibits the highest colour polymorphism. Clownfishes can only disperse during a short pelagic larval phase before their sedentary adult lifestyle, which might limit connectivity among populations, thus facilitating speciation events. Consequently, the taxonomic status of A. clarkii has been under debate. We used whole-genome resequencing data of 67 A. clarkii specimens spread across the Indian and Pacific Oceans to characterize the species' population structure, demographic history and colour polymorphism. We found that A. clarkii spread from the Indo-Pacific Ocean to the Pacific and Indian Oceans following a stepping-stone dispersal and that gene flow was pervasive throughout its demographic history. Interestingly, colour patterns differed noticeably among the Indonesian populations and the two populations at the extreme of the sampling distribution (i.e. Maldives and New Caledonia), which exhibited more comparable colour patterns despite their geographic and genetic distances. Our study emphasizes how whole-genome studies can uncover the intricate evolutionary past of wide-ranging species with diverse phenotypes, shedding light on the complex nature of the species concept paradigm.
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Affiliation(s)
- Sarah Schmid
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
| | | | | | - Joris A M Bertrand
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
| | - Fabio Cortesi
- Queensland Brain Institute, the University of Queensland, Brisbane, Queensland, Australia
- School of the Environment, The University of Queensland, Brisbane, Queensland, Australia
| | - Sara Heim
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
| | - Filip Huyghe
- Marine Biology Laboratory, Department of Ecology and Biodiversity, Vrije Universiteit Brussel, Brussel, Belgium
| | - Glenn Litsios
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
| | - Anna Marcionetti
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
| | - James L O'Donnell
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, USA
| | - Cynthia Riginos
- School of the Environment, The University of Queensland, Brisbane, Queensland, Australia
| | - Valerio Tettamanti
- Queensland Brain Institute, the University of Queensland, Brisbane, Queensland, Australia
| | - Nicolas Salamin
- Department of Computational Biology, University of Lausanne, Lausanne, Switzerland
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Marcionetti A, Bertrand JAM, Cortesi F, Donati GFA, Heim S, Huyghe F, Kochzius M, Pellissier L, Salamin N. Recurrent gene flow events occurred during the diversification of clownfishes of the skunk complex. Mol Ecol 2024; 33:e17347. [PMID: 38624248 DOI: 10.1111/mec.17347] [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: 11/06/2023] [Revised: 03/15/2024] [Accepted: 03/26/2024] [Indexed: 04/17/2024]
Abstract
Clownfish (subfamily Amphiprioninae) are an iconic group of coral reef fish that evolved a mutualistic interaction with sea anemones, which triggered the adaptive radiation of the clade. Within clownfishes, the "skunk complex" is particularly interesting. Besides ecological speciation, interspecific gene flow and hybrid speciation are thought to have shaped the evolution of the group. We investigated the mechanisms characterizing the diversification of this complex. By taking advantage of their disjunct geographical distribution, we obtained whole-genome data of sympatric and allopatric populations of the three main species of the complex (Amphiprion akallopisos, A. perideraion and A. sandaracinos). We examined population structure, genomic divergence and introgression signals and performed demographic modelling to identify the most realistic diversification scenario. We excluded scenarios of strict isolation or hybrid origin of A. sandaracinos. We discovered moderate gene flow from A. perideraion to the ancestor of A. akallopisos + A. sandaracinos and weak gene flow between the species in the Indo-Australian Archipelago throughout the diversification of the group. We identified introgressed regions in A. sandaracinos and detected in A. perideraion two large regions of high divergence from the two other species. While we found that gene flow has occurred throughout the species' diversification, we also observed that recent admixture was less pervasive than initially thought, suggesting a role of host repartition or behavioural barriers in maintaining the genetic identity of the species in sympatry.
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Affiliation(s)
- Anna Marcionetti
- Department of Computational Biology, Génopode, University of Lausanne, Lausanne, Switzerland
| | - Joris A M Bertrand
- Department of Computational Biology, Génopode, University of Lausanne, Lausanne, Switzerland
- Laboratoire Génome et Développement Des Plantes (UMR 5096 UPVD/CNRS), University of Perpignan via Domitia, Perpignan, France
| | - Fabio Cortesi
- School of the Environment and Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Giulia F A Donati
- EAWAG Swiss Federal Institute of Aquatic Science & Technology, Dübendorf, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Sara Heim
- Department of Computational Biology, Génopode, University of Lausanne, Lausanne, Switzerland
| | - Filip Huyghe
- Marine Biology - Ecology, Evolution and Genetics, Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, Belgium
| | - Marc Kochzius
- Marine Biology - Ecology, Evolution and Genetics, Vrije Universiteit Brussel (VUB), Pleinlaan 2, Brussels, Belgium
| | - Loïc Pellissier
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
- Ecosystems and Landscape Evolution, Department of Environmental System Science, Institute of Terrestrial Ecosystems, ETH Zürich, Zurich, Switzerland
| | - Nicolas Salamin
- Department of Computational Biology, Génopode, University of Lausanne, Lausanne, Switzerland
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Stone BW, Wessinger CA. Ecological Diversification in an Adaptive Radiation of Plants: The Role of De Novo Mutation and Introgression. Mol Biol Evol 2024; 41:msae007. [PMID: 38232726 PMCID: PMC10826641 DOI: 10.1093/molbev/msae007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 01/01/2024] [Accepted: 01/10/2024] [Indexed: 01/19/2024] Open
Abstract
Adaptive radiations are characterized by rapid ecological diversification and speciation events, leading to fuzzy species boundaries between ecologically differentiated species. Adaptive radiations are therefore key systems for understanding how species are formed and maintained, including the role of de novo mutations versus preexisting variation in ecological adaptation and the genome-wide consequences of hybridization events. For example, adaptive introgression, where beneficial alleles are transferred between lineages through hybridization, may fuel diversification in adaptive radiations and facilitate adaptation to new environments. In this study, we employed whole-genome resequencing data to investigate the evolutionary origin of hummingbird-pollinated flowers and to characterize genome-wide patterns of phylogenetic discordance and introgression in Penstemon subgenus Dasanthera, a small and diverse adaptive radiation of plants. We found that magenta hummingbird-adapted flowers have apparently evolved twice from ancestral blue-violet bee-pollinated flowers within this radiation. These shifts in flower color are accompanied by a variety of inactivating mutations to a key anthocyanin pathway enzyme, suggesting that independent de novo loss-of-function mutations underlie the parallel evolution of this trait. Although patterns of introgression and phylogenetic discordance were heterogenous across the genome, a strong effect of gene density suggests that, in general, natural selection opposes introgression and maintains genetic differentiation in gene-rich genomic regions. Our results highlight the importance of both de novo mutation and introgression as sources of evolutionary change and indicate a role for de novo mutation in driving parallel evolution in adaptive radiations.
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Affiliation(s)
- Benjamin W Stone
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208-3401, USA
| | - Carolyn A Wessinger
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208-3401, USA
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Stone BW, Wessinger CA. Ecological diversification in an adaptive radiation of plants: the role of de novo mutation and introgression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.01.565185. [PMID: 37961506 PMCID: PMC10635055 DOI: 10.1101/2023.11.01.565185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Adaptive radiations are characterized by rapid ecological diversification and speciation events, leading to fuzzy species boundaries between ecologically differentiated species. Adaptive radiations are therefore key systems for understanding how species are formed and maintained, including the role of de novo mutations vs. pre-existing variation in ecological adaptation and the genome-wide consequences of hybridization events. For example, adaptive introgression, where beneficial alleles are transferred between lineages through hybridization, may fuel diversification in adaptive radiations and facilitate adaptation to new environments. In this study, we employed whole-genome resequencing data to investigate the evolutionary origin of hummingbird-pollinated flowers and to characterize genome-wide patterns of phylogenetic discordance and introgression in Penstemon subgenus Dasanthera, a small and diverse adaptive radiation of plants. We found that magenta hummingbird-adapted flowers have apparently evolved twice from ancestral blue-violet bee-pollinated flowers within this radiation. These shifts in flower color are accompanied by a variety of inactivating mutations to a key anthocyanin pathway enzyme, suggesting that independent de novo loss-of-function mutations underlie parallel evolution of this trait. Although patterns of introgression and phylogenetic discordance were heterogenous across the genome, a strong effect of gene density suggests that, in general, natural selection opposes introgression and maintains genetic differentiation in gene-rich genomic regions. Our results highlight the importance of both de novo mutation and introgression as sources of evolutionary change and indicate a role for de novo mutation in driving parallel evolution in adaptive radiations.
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Affiliation(s)
- Benjamin W. Stone
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208-3401, USA
| | - Carolyn A. Wessinger
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208-3401, USA
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