Insights into the Genetic Diversity of the leopard seal (Hydrurga leptonyx), inferred from mitochondrial DNA analysis, at Danco Coast, Antarctic Peninsula

Abstract

The leopard seal (Hydrurga leptonyx) has a wide distribution throughout the Antarctic circumpolar region. This species has solitary habits, haul out on pack ice for long period, and individuals tend to congregate in the same areas during the mating season. The leopard seal shows site fidelity to reproductive sites, which may imply restricted gene flow between groups. In order to conduct the first assessment of genetic diversity of leopard seals in waters around Danco Coast in the Antarctic Peninsula, we amplified mitochondrial DNA Control Region (mtDNA-CR, 423 bp) from DNA extracted from 13 blood samples collected in Primavera Base (62o15'S, 58o39'W) during 2011-2012 austral summer. Our results showed high haplotype diversity (h = 0.989), represented in one unique haplotype for each sample, and only one haplotype shared between two samples. Network analyses confirmed high diversity with some divergent haplotypes. Our genetic findings suggest that individuals sampled belong to one population. Due to ice dynamic as a consequence of climate change, many individuals are shifting their diet habits, showing dietary specializations that may have the potential to promote genetic differentiation in the long-term. However, given the lack of leopard seals genetic studies, this hypothesis cannot be tested. Research studies using mitochondrial and nuclear markers are needed to assess the genetic status of leopard seals and their population structure in relation with other populations, particularly to determine restrictions to gene flow likely related to dietary specialization among leopard seals populations.