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Schartl M, Kneitz S, Ormanns J, Schmidt C, Anderson JL, Amores A, Catchen J, Wilson C, Geiger D, Du K, Garcia-Olazábal M, Sudaram S, Winkler C, Hedrich R, Warren WC, Walter R, Meyer A, Postlethwait JH. The Developmental and Genetic Architecture of the Sexually Selected Male Ornament of Swordtails. Curr Biol 2021; 31:911-922.e4. [PMID: 33275891 PMCID: PMC8580132 DOI: 10.1016/j.cub.2020.11.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/12/2020] [Accepted: 11/11/2020] [Indexed: 12/21/2022]
Abstract
Sexual selection results in sex-specific characters like the conspicuously pigmented extension of the ventral tip of the caudal fin-the "sword"-in males of several species of Xiphophorus fishes. To uncover the genetic architecture underlying sword formation and to identify genes that are associated with its development, we characterized the sword transcriptional profile and combined it with genetic mapping approaches. Results showed that the male ornament of swordtails develops from a sexually non-dimorphic prepattern of transcription factors in the caudal fin. Among genes that constitute the exclusive sword transcriptome and are located in the genomic region associated with this trait we identify the potassium channel, Kcnh8, as a sword development gene. In addition to its neural function kcnh8 performs a known role in fin growth. These findings indicate that during evolution of swordtails a brain gene has been co-opted for an additional novel function in establishing a male ornament.
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Affiliation(s)
- Manfred Schartl
- Developmental Biochemistry, Biocenter, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany; The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA.
| | - Susanne Kneitz
- Biochemistry and Cell Biology, Biocenter, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany
| | - Jenny Ormanns
- Biochemistry and Cell Biology, Biocenter, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany
| | - Cornelia Schmidt
- Biochemistry and Cell Biology, Biocenter, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany
| | - Jennifer L Anderson
- Systematic Biology, Department of Organismal Biology, Uppsala University, Norbyvägen 18D, 752 36 Uppsala, Sweden
| | - Angel Amores
- Institute of Neuroscience, University of Oregon, Eugene, OR 97401, USA
| | - Julian Catchen
- Department of Animal Biology, University of Illinois, Urbana, IL 6812, USA
| | - Catherine Wilson
- Institute of Neuroscience, University of Oregon, Eugene, OR 97401, USA
| | - Dietmar Geiger
- Julius-von-Sachs-Institute for Biosciences, Molecular Plant Physiology and Biophysics, Biocenter, University Würzburg, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany
| | - Kang Du
- Developmental Biochemistry, Biocenter, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany; The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | | | - Sudha Sudaram
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Christoph Winkler
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Rainer Hedrich
- Julius-von-Sachs-Institute for Biosciences, Molecular Plant Physiology and Biophysics, Biocenter, University Würzburg, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany
| | - Wesley C Warren
- 440G Bond Life Sciences Center, 1201 Rollins Street, University of Missouri, Columbia, MO 65211, USA
| | - Ronald Walter
- The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Axel Meyer
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany.
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Meyer A, Morrissey JM, Schartl M. Recurrent origin of a sexually selected trait in Xiphophorus fishes inferred from a molecular phylogeny. Nature 1994; 368:539-42. [PMID: 8139686 DOI: 10.1038/368539a0] [Citation(s) in RCA: 173] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Darwin believed that sexual selection accounts for the evolution of exaggerated male ornaments, such as the sword-like caudal fin extensions of male fishes of the genus Xiphophorus, that appear detrimental to survival. Swordtails continue to feature prominently in empirical work and theories of sexual selection; the pre-existing bias hypothesis has been offered as an explanation for the evolution of swords in these fishes. Based upon a largely morphological phylogeny, this hypothesis suggests that female preference to mate with sworded males arose in ancestrally swordless species, thus pre-dating the origin of the sword itself and directly driving its evolution. Here we present a molecular phylogeny (based on mitochondrial and nuclear DNA sequences) of Xiphophorus which differs from the traditional one: it indicates that the sword originated and was lost repeatedly. Our phylogeny suggests that the ancestor of the genus is more likely to have possessed a sword than not, thus questioning the applicability of the pre-existing bias hypothesis as an explanation for the evolution of this sexually selected trait.
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Affiliation(s)
- A Meyer
- Department of Ecology and Evolution, State University of New York, Stony Brook 11794-5245
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