Mitochondrial DNA variation in Atlantic and Pacific walruses

Abstract

We used restriction enzyme analysis of polymerase chain reaction amplified mitochondrial DNA to assess genetic differentiation of two subspecies of walruses: Atlantic walruses (Odobenus rosmarus rosmarus) from Greenland and Pacific walruses (O. r. divergens) from the Chukchi Sea. Each subspecies has distinct monophyletic mitochondrial DNA haplotypes. Mitochondrial DNA sequence divergence between Atlantic and Pacific subspecies was 1.0–1.6%. Several haplotypes were observed for each subspecies. Haplotype frequencies varied among sampling locations of Atlantic walruses, suggesting that mitochondrial DNA may be useful for walrus stock identification.