Population genetic structure of North American burbot (Lota lota maculosa) across the Nearctic and at its contact zone with Eurasian burbot (Lota lota lota)

Abstract

The burbot, Lota lota (Teleostei: Gadidae), has a holarctic distribution, with one subspecies ( Lota lota lota ) living in the lakes and rivers of the Palaearctic and northwestern North America and the other ( Lota lota maculosa ) living in the Nearctic (except the northwest). We analysed nine microsatellite loci and the mitochondrial DNA control region of 350 burbot sampled across North America to develop a continent-wide understanding of population differentiation following postglacial recolonization. Using mitochondrial DNA, we identify three subclades of L. l. maculosa: one is widespread, one is moderately well distributed, and the third is restricted to the southwest. Lota l. lota is restricted to Yukon and Alaska. Microsatellite loci show moderate levels of genetic diversity and high population differentiation throughout North America (Rst ≤ 0.9). Lota l. maculosa and L. l. lota mtDNA lineages only co-occur appreciably in Great Slave Lake. An individual-based Bayesian approach to detect genotypic admixture indicates that very few of all individuals show signs of admixture between subspecies, and those individuals are restricted to Great Slave Lake and Lake Laberge.