Harp Seals comprise four populations associated with whelping areas on pack ice in the Greenland Sea, White Sea, and Northwest Atlantic “Gulf” and “Front”. Complete mitochondrial DNA genome sequences have identified nearly 600 single-nucleotide polymorphisms ("SNPs"). Every individual has a unique mtDNA sequence. The figure shows evidence for the existence of a deep ancestral clade (F) confined primarily to the eastern populations, and relatively close relationships within and between western populations in a more recent clade (A). A Monte Carlo simulation shows that the distribution of seals over the tree is non-random, and non-parametric analysis shows that individuals from the Greenland Sea are part of a substantially younger distribution than in the White Sea. This study is the first to show genetic evidence for distinctive populatiions in the Greenland Sea and White Sea.