A comparison of diversity in the zfy gene in two species of pinnipeds with different breeding strategies

Sequence variation was examined for the Zinc-finger Y (zfy) gene and the mitochondrial control region for two species of pinnipeds, the Steller sea lion (Eumetopias jubatus) and harbor seal (Phoca vitulina). The two species differ in aspects of their breeding strategies, dispersal, and life histories. Comparable stock sample sizes of males from each species were taken from localities that span at least one wellrecognized phylogeographic stock as defined by mtDNA markers. Variation in zfy, a strictly paternally inherited marker located on the Y chromosome, was low in both species. An interesting pattern of subdivision was found for zfy in harbor seals that was concordant with population subdivision for mtDNA. In Steller sea lions, no such concordant pattern was evident with only a single rare zfy variant being observed. One explanation for the different patterns observed is that dispersal is less in male harbor seals than in male Steller sea lions.