The role of Pleistocene glaciations in shaping the genetic structure of South American fur seals (Arctocephalus australis)

Abstract

Analysing a 529 bp segment of the mitochondrial control region, we evaluated the role that Pleistocene glaciations may have had in shaping the genetic structure currently found in the two southernmost breeding areas of the South American fur seal, Arctocephalus australis. Additionally, we analysed if these two breedingareas correspond to different conservation units. We found 26 haplotypes in 54 individuals. Colonies from the Uruguayan breeding area did not show significant differences in haplotype frequencies, which suggest that they are remnants of a single ancient gene pool. The genealogical relationship between haplotypes revealed a pattern of phylogeographic structure with two main haplogroups corresponding to the different breeding areas. The analysis of molecular variance and the estimate of population divergence time also indicated significant genetic differences and a long period of isolation between Atlantic and Pacific colonies, suggesting that these breeding areas would correspond to different conservation units.