Original Article | Published:

Phylogenomics of the killer whale indicates ecotype divergence in sympatry

Heredity volume 114, pages 4855 (2015) | Download Citation

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Abstract

For many highly mobile species, the marine environment presents few obvious barriers to gene flow. Even so, there is considerable diversity within and among species, referred to by some as the ‘marine speciation paradox’. The recent and diverse radiation of delphinid cetaceans (dolphins) represents a good example of this. Delphinids are capable of extensive dispersion and yet many show fine-scale genetic differentiation among populations. Proposed mechanisms include the division and isolation of populations based on habitat dependence and resource specializations, and habitat release or changing dispersal corridors during glacial cycles. Here we use a phylogenomic approach to investigate the origin of differentiated sympatric populations of killer whales (Orcinus orca). Killer whales show strong specialization on prey choice in populations of stable matrifocal social groups (ecotypes), associated with genetic and phenotypic differentiation. Our data suggest evolution in sympatry among populations of resource specialists.

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Acknowledgements

We thank Howard Gray for providing primer sequences for the amplification of mitochondrial DNA, and Charlene Janse van Rensburg and Colin Nicholson for labwork associated with DNA extraction and archiving. This study was funded by the Natural Environment Research Council UK (grant number NE/014443/1). We thank the South African Department of Environmental Affairs for providing logistical support within the South African National Antarctic Programme and the Department of Science and Technology (administered through the South African National Research Foundation) for funding the marine mammal monitoring programme at Marion Island.

Author information

Author notes

    • A E Moura

    Current address: School of Life Sciences, University of Lincoln, Lincoln LN2 2LG, UK.

    • R R Chaudhuri

    Current address: Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank Sheffield, S10 2TN, UK.

Affiliations

  1. School of Biological and Biomedical Sciences, Durham University, Durham, UK

    • A E Moura
    •  & A R Hoelzel
  2. Department of Functional and Comparative Genomics, Institute of Integrative Biology, University of Liverpool, Liverpool, UK

    • J G Kenny
    • , R R Chaudhuri
    • , M A Hughes
    •  & N Hall
  3. Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa

    • R R Reisinger
    •  & P J N de Bruyn
  4. National Marine Mammal Laboratory, National Marine Fisheries Service, Seattle, WA, USA

    • M E Dahlheim

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Competing interests

The authors declare no conflict of interest.

Corresponding author

Correspondence to A R Hoelzel.

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DOI

https://doi.org/10.1038/hdy.2014.67

Supplementary Information accompanies this paper on Heredity website (http://www.nature.com/hdy)

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