Comparative characteristics of the genetic polymorphism of populations of Chinese sleeper Perccottus glenii (Perciformes, Odontobutidae) in the Volga and Irtysh basins.

The level of genetic diversity and differentiation of populations of the Chinese sleeper Perccottus glenii from water bodies of the Volga and Irtysh basins was assessed based on ISSR markers. In the studied part of the Volga basin, the proportion of polymorphic loci (P) of the Chinese sleeper was 80.4%, genetic diversity (h) was 0.26. All studied populations of the Chinese sleeper from the Kuibyshev Reservoir area (Ulyanovsk, Samara region, Togliatti) were genetically weakly differentiated and originate from a single source of invasion. The polymorphism and genetic diversity of the Chinese sleeper in the Irtysh basin were higher than in the Volga region and amounted to: P = 98.2%, h = 0.33. Genetic differentiation between the populations of the Ipkul Lake and the Tobol River (Tyumen region) was weakly expressed (GST = 0.07), the gene flow between them was significant, which indicates their recent divergence or the origin of one population from another. The genetic differentiation between the populations of Lake Berezovo (Kurgan region) and Lake Maloe Ploskoe (Kazakhstan) was high (GST = 0.31), which may indicate different sources of invasion of the Chinese sleeper in southern Siberia and northern Kazakhstan. Data on the higher polymorphism of the Chinese sleeper in the Irtysh River basin, as well as significant genetic differentiation between its populations in the Volga and Irtysh basins (GST = 0.40), only partially confirm the generally accepted hypothesis of the colonization of Siberia by the Chinese sleeper through the South Ural invasion corridor, indicating the presence of several heterogeneous invasion sources in the Ob–Irtysh basin.