loading page

Population genomics reveals historical divergence and local adaptation in polar bears
  • +11
  • René Malenfant,
  • Catherine Cullingham,
  • David Coltman,
  • Evan Richardson,
  • Markus Dyck,
  • Nicholas Lunn,
  • Martyn Obbard,
  • Jodie Pongracz,
  • Stephen Atkinson,
  • Vicki Sahanatien,
  • Kristin Laidre,
  • Erik Born,
  • Øystein Wiig,
  • Corey Davis
René Malenfant
University of New Brunswick

Corresponding Author:[email protected]

Author Profile
Catherine Cullingham
University of Alberta
Author Profile
David Coltman
University of Alberta
Author Profile
Evan Richardson
Environment and Climate Change Canada
Author Profile
Markus Dyck
Government of Nunavut
Author Profile
Nicholas Lunn
Environment and Climate Change Canada Prairie and Northern Region
Author Profile
Martyn Obbard
Ontario Ministry of Natural Resources and Forestry
Author Profile
Jodie Pongracz
Government of the Northwest Territories
Author Profile
Stephen Atkinson
Author Profile
Vicki Sahanatien
University of Alberta
Author Profile
Kristin Laidre
University of Washington Applied Physics Laboratory
Author Profile
Erik Born
Gronlands Naturinstitut
Author Profile
Øystein Wiig
University of Oslo
Author Profile
Corey Davis
University of Alberta
Author Profile


Single-nucleotide polymorphisms (SNPs) have numerous advantages over microsatellites, including greater power to infer population structure and history and to detect loci undergoing selection. Here, we conduct the first continental-level SNP study of polar bears (Ursus maritimus) using genotypes from an array of 5441 SNP loci genotyped in 16–30 polar bears sampled in each of 16 geographic regions in Canada and West Greenland. Our study aimed to assess population history and genetic structure and to identify evidence of adaptive loci. Using these data, we confirmed the existence of four broad-scale genetic clusters in North America (FCT = 0.035) and identified nine fine-scale subclusters using more powerful spatial methods. An assessment of historical patterns of migration suggests that polar bears migrated into North America from the Beaufort Sea after the last glacial maximum. Using a conservative approach, we identified 17 loci that may represent adaptive variation, including one SNP in the 3’ untranslated region of PDLIM5 (PDZ And LIM Domain 5), a gene involved in cardiovascular function, which has undergone substantial selection in polar bears since their divergence from brown bears. Outlier loci differentiated the Norwegian Bay genetic cluster more strongly from remaining clusters than did our complete dataset, suggesting possible adaptive differences in the High Arctic. Through careful consideration of SNP loci, sample inclusion, and analytical approaches, we provide a comprehensive picture of polar bear population structure at a continental level. This study provides a model for the analysis of wide-ranging species that can contribute to their conservation and management.
07 Feb 2020Submitted to Molecular Ecology
21 Feb 2020Reviewer(s) Assigned
16 Mar 2020Review(s) Completed, Editorial Evaluation Pending