Trans-oceanic kinship in the sperm whale ( Physeter macrocephalus )

The question of connectivity and dispersal range in the oceans is important because it informs about evolutionary process and speciation, and for conservation, through the identification of cryptic patterns of diversity. Natural boundaries to dispersal are less obvious in marine compared with terrestrial environments and may include oceanographic factors, potentially affecting the distribution of prey. While some cetacean species show surprisingly strong patterns of population structure despite the lack of obvious physical boundaries to dispersal, others are relatively panmictic. Here we focus on the pattern and potential range of dispersal in the largest of the odontocete (toothed whale) species, the sperm whale, a species that shows weak population structure. We compare kinship within and among populations either side of the North Atlantic, and using whole nuclear genomes, we confirm close kinship between a male sampled in the North Sea and a female offspring pair sampled in the Gulf of Mexico.