Loss of maternal lineages in Antarctic blue whales described from whole mitochondrial genomes of historical and contemporary samples
Angela L. Sremba, Aimee R. Lang, Nedda Saremi, Beth Shapiro, Robert Pitman, Peter Wilson, Anthony R. Martin, C. Scott Baker
International Whaling Commission
During the 20th century, the Antarctic blue whale was heavily exploited by the commercial whaling industry with over 340,000 whales killed, reducing the population to less than 0.1% of its pre-exploitation abundance. This exploitation began on the South Atlantic island of South Georgia and in various whaling stations around the Antarctic Peninsula. Over one hundred years later, bones of whales killed by the early commercial whaling industry in the Southern Hemisphere lay scattered along the shorelines and abandoned whaling stations. These bones have preserved the genomic diversity of pre-exploitation Antarctic blue whales and offer the opportunity to explore the impact of exploitation on genomic diversity through comparison to contemporary populations. Using next-generation sequencing (Illumina HiSeq), we reconstructed 18 distinct mitochondrial genomes from 20 blue whale bones collected from South Georgia and the Antarctic Peninsula. We compared these to 53 distinct mitogenomes from 73 contemporary samples considered to be Antarctic blue whale. From this comparison, we resolved a total of 69 unique mitogenome haplotypes of which only two were shared between the historical and contemporary samples. The sharing of only two of the mitogenome haplotypes between the historical and contemporary samples suggests a loss of maternal lineages due to 20th century whaling.