Reconstruction of caribou evolutionary history in Western North America and its implications for conservation

Byron V. Weckworth, Marco Musiani, Allan D. McDevitt, Mark Hebblewhite, Stefano Mariani

Research output: Contribution to journalReview articlepeer-review

45 Scopus citations

Abstract

The role of Beringia as a refugium and route for trans-continental exchange of fauna during glacial cycles of the past 2 million years are well documented; less apparent is its contribution as a significant reservoir of genetic diversity. Using mitochondrial DNA sequences and 14 microsatellite loci, we investigate the phylogeographic history of caribou (Rangifer tarandus) in western North America. Patterns of genetic diversity reveal two distinct groups of caribou. Caribou classified as a Northern group, of Beringian origin, exhibited greater number and variability in mtDNA haplotypes compared to a Southern group originating from refugia south of glacial ice. Results indicate that subspecies R. t. granti of Alaska and R. t. groenlandicus of northern Canada do not constitute distinguishable units at mtDNA or microsatellites, belying their current status as separate subspecies. Additionally, the Northern Mountain ecotype of woodland caribou (presently R. t. caribou) has closer kinship to caribou classified as granti or groenlandicus. Comparisons of mtDNA and microsatellite data suggest that behavioural and ecological specialization is a more recently derived life history characteristic. Notably, microsatellite differentiation among Southern herds is significantly greater, most likely as a result of human-induced landscape fragmentation and genetic drift due to smaller population sizes. These results not only provide important insight into the evolutionary history of northern species such as caribou, but also are important indicators for managers evaluating conservation measures for this threatened species.

Original languageEnglish
Pages (from-to)3610-3624
Number of pages15
JournalMolecular Ecology
Volume21
Issue number14
DOIs
StatePublished - Jul 2012

Keywords

  • Rangifer tarandus
  • ecotypes
  • endangered species
  • genetic markers
  • phylogeography
  • subspecies

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