Origin and expansion of the world’s most widespread pinniped : range-wide population genomics of the harbour seal (Phoca vitulina)

• Published in: Molecular Ecology
• Main Authors: Liu, Xiaodong, Schjøtt, Suzanne Rønhøj, Granquist, Sandra M., Rosing-Asvid, Aqqalu, Dietz, Rune, Teilmann, Jonas, Galatius, Anders, Cammen, Kristina, O´Corry-Crowe, Greg, Harding, Karin, Härkönen, Tero, Hall, Ailsa, Carroll, Emma L., Kobayashi, Yumi, Hammill, Mike, Stenson, Garry, Frie, Anne Kirstine, Lydersen, Christian, Kovacs, Kit M., Andersen, Liselotte W., Hoffman, Joseph I., Goodman, Simon J., Vieira, Filipe G., Heller, Rasmus, Moltke, Ida, Tange Olsen, Morten
• Other Authors: NERC, University of St Andrews. School of Biology, University of St Andrews. Sea Mammal Research Unit, University of St Andrews. Scottish Oceans Institute, University of St Andrews. Marine Alliance for Science & Technology Scotland
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2022
• Subjects: Colonisation; Genetic diversity; Harbour seals; Origin; Population structure; Subspecies delineation; QH301 Biology; QH426 Genetics; DAS; NERC; QH301; QH426; harbour seal; North Atlantic; Phoca vitulina
• Online Access: https://hdl.handle.net/10023/24837; https://doi.org/10.1111/mec.16365

The study was partly conducted under a Villum Foundation Young Investigator grant (19114) awarded to IM, which also supports XL, as well as the BONUS BALTHEALTH project (Art. 185) awarded to RDI, AG, TH and MTO. BONUS BALTHEALTH was funded jointly by the EU, Innovation Fund Denmark (grants 6180-00001B and 6180-00002B), Forschungszentrum Jülich GmbH, German Federal Ministry of Education and Research (grant FKZ 03F0767A), Academy of Finland (grant 311966) and Swedish Foundation for Strategic Environmental Research (MISTRA). The harbour seal (Phoca vitulina) is the most widely distributed pinniped, occupying a wide variety of habitats and climatic zones across the Northern Hemisphere. Intriguingly, the harbour seal is also one of the most philopatric seals, raising questions as to how it colonised virtually the whole of the Northern Hemisphere. To shed light on the origin, remarkable range expansion, population structure and genetic diversity of this species, we used genotyping-by-sequencing to analyse ~13,500 biallelic SNPs from 286 individuals sampled from 22 localities across the species' range. Our results point to a Northeast Pacific origin, colonisation of the North Atlantic via the Canadian Arctic, and subsequent stepping-stone range expansions across the North Atlantic from North America to Europe, accompanied by a successive loss of genetic diversity. Our analyses further revealed a deep divergence between modern North Pacific and North Atlantic harbour seals, with finer-scale genetic structure at regional and local scales consistent with strong philopatry. The study provides new insights into the harbour seal's remarkable ability to colonise and adapt to a wide range of habitats. Furthermore, it has implications for current harbour seal subspecies delineations and highlights the need for international and national red lists and management plans to ensure the protection of genetically and demographically isolated populations. Peer reviewed