Historical population size change of bowhead whales inferred from DNA sequence polymorphism data

Nucleotide sequence data from the mitochondrial control region were used fr om a phylogenetic context to investigate the long-term history of a populat ion of bowhead whales (Balaena mysticetus). In addition, the coalescence ti me of these sequences was used to estimate the age of the inferred patterns of population size change. The results indicate that mitochondrial genetic polymorphism was not affected by a recent bottleneck that occurred near th e turn of the 20th century. thereby preserving the signature of historical population size change in the mitochondrial genome. Further analysis showed that this population underwent an expansion initiated in the Middle to Lat e Pleistocene. As such, early Holocene changes in Arctic sea ice distributi on appear to have had little influence on patterns of genetic variability i n this population.