What influences the worldwide genetic structure of sperm whales (Physeter macrocephalus)?

To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by John Wiley & Sons, Ltd. and can be found at: http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291365-294XGenetic samples from the 'Voyage of the Odyssey' were collected under permit #0751-1614 from the US National Marine Fisheries Service.Data accessibility: For each sample genotyped in this study, general location\ud (as well as latitude/longitude where available),\ud individual ID code, social group code, sex, microsatellite\ud genotype and a letter code denoting the mtDNA CR\ud haplotype (defined in Appendix S1, Supporting information)\ud are archived with Dryad (doi: 10.5061/\ud dryad.2q4r0).\ud Sequences of each defined haplotype have been\ud archived on NCBI GenBank (Accession nos: KU719571–\ud KU719622).\ud Scripts used in analyses are available with online\ud Supplementary Materials or at https://github.com/\ud laninsky/genetic_diversity_diffs.The interplay of natural selection and genetic drift, influenced by geographic isolation, mating systems and population size, determines patterns of genetic diversity within species. The sperm whale provides an interesting example of a long-lived species with few geographic barriers to dispersal. Worldwide mtDNA diversity is relatively low, but highly structured among geographic regions and social groups, attributed to female philopatry. However, it is unclear whether this female philopatry is due to geographic regions or social groups, or how this might vary on a worldwide scale. To answer these questions, we combined mtDNA information for 1091 previously published samples with 542 newly obtained DNA profiles (394-bp mtDNA, sex, 13 microsatellites) including the previously unsampled Indian Ocean, and social group information for 541 individuals. We found low mtDNA diversity (π = 0.430%) reflecting an expansion event