Analysis of the genetic structure of populations of the terrestrial mollusk Caucasotachea vindobonensis (Helicidae) in conditions at the eastern border of the range using microsatellite markers

Abstract

BACKGROUND: The aim of the study was to study the genetic structure of Caucasotachea vindobonensis populations in the south of the Central Russian Upland using SSR markers. MATERIALS AND METHODS Genetic structure of the populations was studied using eight microsatellite markers, first identified by the authors for the species under study. Fragment analysis of PCR products was carried out on an automatic capillary DNA sequencer Nanophore 05 (IAP RAS, Russia). A total of 498 individuals from 24 populations were studied. RESULTS: A total of 59 alleles were isolated in the eight studied STR loci, of which 21 (36%) turned out to be private. At the same time, private alleles were found in eleven studied populations, which is 46% of their total number. According to the data obtained, the effective number of alleles (Ae) averaged 1.6±0.06, the Chenon index (I) was 0.45±0.03, and the level of expected heterozygosity (He) was 0.27±0.021. A high level of spatial subdivision of population gene pools was noted (Fst=0.47±0.08) with a fairly low level of gene flow (Nm=1.15±0.91). PCA analysis showed that the populations of the central and eastern parts of the south of the Central Russian Upland form a closely related group, different from other populations of the region. Calculation of the effective abundance using the LD method showed that NeLd varies in different groups of snails from 0.6 to infinity. CONCLUSIONS: Populations of C. vindobonensis in the south of the Central Russian Upland live in conditions of significant isolation, as evidenced by the high degree of differentiation of the studied groups. The analysis of principal components based on genetic distances according to Nei and Wright's F-statistics indicate a pronounced division of populations in the study area into two clusters, which is probably associated with the historical features of landscape formation. Calculation of effective numbers indicates the high viability of the majority of the studied populations. At the same time, some groups of snails are clearly in a depressed state, which is reflected in low levels of genetic diversity and their effective size.