Genomic signatures of divergent selection are associated with social behaviour for spinner dolphin ecotypes

Kimberly R. Andrews, Brendan Epstein, Matthew S. Leslie, Paul Fiedler, Phillip A. Morin, A. Rus Hoelzel

Research output: Contribution to journalArticlepeer-review

Abstract

Understanding the genomic basis of adaptation is critical for understanding evolutionary processes and predicting how species will respond to environmental change. Spinner dolphins in the eastern tropical Pacific (ETP) present a unique system for studying adaptation. Within this large geographical region are four spinner dolphin ecotypes with weak neutral genetic divergence and no obvious barriers to gene flow, but strong spatial variation in morphology, behaviour and habitat. These ecotypes have large population sizes, which could reduce the effects of drift and facilitate selection. To identify genomic regions putatively under divergent selective pressures between ecotypes, we used genome scans with 8994 RADseq single nucleotide polymorphisms (SNPs) to identify population differentiation outliers and genotype–environment association outliers. Gene ontology enrichment analyses indicated that outlier SNPs from both types of analyses were associated with multiple genes involved in social behaviour and hippocampus development, including 15 genes associated with the human social disorder autism. Evidence for divergent selection on social behaviour is supported by previous evidence that these spinner dolphin ecotypes differ in mating systems and associated social behaviours. In particular, three of the ETP ecotypes probably have a polygynous mating system characterized by strong premating competition among males, whereas the fourth ecotype probably has a polygynandrous mating system characterized by strong postmating competition such as sperm competition. Our results provide evidence that selection for social behaviour may be an evolutionary force driving diversification of spinner dolphins in the ETP, potentially as a result of divergent sexual selection associated with different mating systems. Future studies should further investigate the potential adaptive role of the candidate genes identified here, and could probably find further signatures of selection using whole genome sequence data.

Original languageEnglish (US)
Pages (from-to)1993-2008
Number of pages16
JournalMolecular ecology
Volume30
Issue number9
DOIs
StatePublished - May 2021

Bibliographical note

Funding Information:
We extend sincere thanks to the scientists who collected the specimens used in this study, including the National Marine Fisheries Service West Coast Region Observer Program; Tim Gerrodette, Karin Forney and Lisa Ballance from the Southwest Fisheries Science Center; and the Instituto Nacional De La Pesca. These collections provided archival biomaterial to answer questions never imagined possible during the sampling efforts. We also thank William F. Perrin for providing support and guidance, and the staff at the SWFSC Marine Mammal and Sea Turtle Research Collection for providing technical support for molecular laboratory work, including Gabriela Serra‐Valente, Victoria Pease, Kelly Robertson, Louella Dolar, Nicole Beaulieu and Morgane Lauf. We thank Brenna Forester for helpful comments on the manuscript. KRA was supported by a European Union Marie Curie International Incoming Fellowship.

Funding Information:
We extend sincere thanks to the scientists who collected the specimens used in this study, including the National Marine Fisheries Service West Coast Region Observer Program; Tim Gerrodette, Karin Forney and Lisa Ballance from the Southwest Fisheries Science Center; and the Instituto Nacional De La Pesca. These collections provided archival biomaterial to answer questions never imagined possible during the sampling efforts. We also thank William F. Perrin for providing support and guidance, and the staff at the SWFSC Marine Mammal and Sea Turtle Research Collection for providing technical support for molecular laboratory work, including Gabriela Serra-Valente, Victoria Pease, Kelly Robertson, Louella Dolar, Nicole Beaulieu and Morgane Lauf. We thank Brenna Forester for helpful comments on the manuscript. KRA was supported by a European Union Marie Curie International Incoming Fellowship.

Publisher Copyright:
© 2021 The Authors. Molecular Ecology published by John Wiley & Sons Ltd.

Keywords

  • F outlier tests
  • Stenella longirostris
  • environmental association analysis
  • genome scan
  • genotype–environment association
  • mating system

PubMed: MeSH publication types

  • Journal Article
  • Research Support, Non-U.S. Gov't

Fingerprint

Dive into the research topics of 'Genomic signatures of divergent selection are associated with social behaviour for spinner dolphin ecotypes'. Together they form a unique fingerprint.

Cite this