We have used Daphnia cucullata as a model organism for the first time in the four deepest Latvian lakes from the Boreal biogeographical region lakes in order to find the genetic diversity of Daphnia cucullata populations. During the research, the most appropriate microsatellite markers for future genetic studies of Daphnia cucullata populations in Boreal biogeographical region lakes. It was the loci Dgm105 and Dgm101, in which the maximum number of alleles and the maximum number of private alleles were found. The Dgm105 locus had five private alleles (62% of all detected alleles), while the Dgm101 locus had four private alleles (57% of all detected alleles) in these loci. We was determined the observed heterozygosity (Hobs) and the expected heterozygosity (Hexp) level (by Hardy-Weinberg), the number of polymorphic loci, the number of detected alleles in each analyzed microsatellite locus, the average number of alleles at the locus (Na), the average effective number of alleles at the locus (Ne), FST of the population genetic differentiation, the genetic distance (D) (by Nei) and significance (χ2- test) of differences between the levels of observed and expected heterozygosity.
It was shown that Daphnia cucullata populations from lakes with a low number of zooplankton taxa (Riča and Geraņimovas-Ilzas) have a higher genetic diversity compared to lakes with a high number of zooplankton taxa (Dridzis and Svente) in lakes. It was found, that Daphnia cucullata populations from lakes Dridzis and Svente have the least genetic distance and these populations form a single genetic group, as confirmed by clustering