Population genetics of woodland caribou (Rangifer tarandus caribou) on the island of Newfoundland

The purpose of this study was to characterize the genetic variation and genetic structure of caribou herds on the island of Newfoundland. A 2223 bp sequence of mitochondrial DNA from the Control Region and the cytochrome b gene was sequenced for 233 Newfoundland caribou (Rangifer tarandus caribou). Phylogenetic analysis identified 32 mtDNA haplotypes structured into four clades, labeled A, B, C and D. The hierarchical AMOVA revealed there is little genetic differentiation among defined herds, although there is some regional differentiation of the Avalon Peninsula. Avalon Peninsula caribou are genetically depauperate and distinct, possibly as a result of founder effects. The Nested Clade Analysis identified significant phylogeographic associations possibly due to restricted gene flow with isolation by distance, contiguous range expansion and long distance colonization possibly coupled with subsequent fragmentation or past fragmentation followed by range expansion. Most Newfoundland caribou show close relationships to woodland caribou in Quebec, and a small subset show close relationships to woodland caribou in Labrador. There is some genetic evidence to suggest that caribou populated Newfoundland by way of the Straight of Belle Isle as opposed to coastal refugia. Newfoundland caribou are genetically distinct from Eurasian reindeer (Rangifer tarandus tarandus) and there is no evidence to support successful interbreeding with reindeer introduced from Norway. In anticipation of continuing population genomic studies of Newfoundland caribou, the entire mtDNA genome for one Newfoundland caribou was sequenced (16,359 bp)