A note on the genetic diversity of sperm whales in the western North Pacific as revealed by mitochondrial and microsatellite DNA

Genetic variation at 15 microsatellite DNA loci and mitochondrial DNA (mtDNA) control region sequences (338bp) was examined in sperm whales collected during JARPNII from 2000 to 2013 in order to examine the effectiveness of these genetic markers for studies of stock structure in this species. Analyses of mtDNA and microsatellite markers in a total of 56 sperm whales (16 males; 40 females) confirmed that these genetic markers were variable enough to explore stock structure of sperm whales. The overall heterozygosity over 15 loci was 0.730 while the nucleotide and haplotype diversity were 0.0038 and 0.7188, respectively. Statistical tests found no evidence of deviation from the expected HardyWeinberg genotypic proportion at all of the 15 microsatellite loci. At this point, no signal of multiple stocks of sperm whale in the western North Pacific off Japan was detected.