Genetics of the peripheral populations of the alpine bullhead, Cottus poecilopus (Scorpaeniformes, Cottidae) in Poland

The alpine bullhead (Cottus poecilopus ) in Poland is highly polymorphic (P for examined populations in the range of 0.0-0.45, mean P = 0.11, P for species 0.64) in seven out of 11 loci studied (Pgd-1, Mdh-1, Ck-1, Gpd-1, Gpd-2, Gpi-1, Gpi-2 ). However, they reveal very low heterozygosity (mean H (o) = 0.007, mean H (e) = 0.019), which may result from population subdivisions, small genetically effective size (N (e) ) of some populations and frequent inbreeding, the latter being probably mediated through polygyny. The index of genetic differentiation (G (ST) ) for the Polish metapopulation equals 0.48, which is relatively high. By far, the strongest are genetic differences between the Sudeten-Carpathian group and the Hancza population. Gene flow between the Sudeten-Carpathian group and the Hancza population is very limited and their divergence may have started as early as the last (Eemian) interglacial period.