Wolf-dog hybrids arise: new insight into the eastern fringe of the Northern European wolf population

Abstract

In this study, tissue samples of 35 wolves hunted in Russian Karelia and 12 specimens of dogs were used in 2012-2022 for genetic analysis. Four of the wolves (11%) were recognized by to phenotypic characteristics as wolf-dog hybrids (WDH). The analysis of 11 autosomal STRs confirmed the hybrid origin of three and excluded one. At the same time, two more admixed individuals with no phenotypic deviations were additionally identified, raising the total number of hybrids to five (14%). The analysis of CR1 mtDNA in the specified sample set revealed the dog haplotype in one of the phenotypically inferred WDH. The mtDNA haplotype diversity was represented by two haplotypes common in Eurasia. The genetic diversity level of the population revealed by 11 microsatellite loci was high (He = 0.746; Ho = 0.655; A = 8). However, the observed heterozygosity proved to be notably lower than expected, and the inbreeding coefficient was also high (Fis = 0.131) and, moreover, higher than the previously reported (Aspi et al. 2009). The wolf population of Karelia used to be considered as pure wolves, with a moderate level of hunting pressure. The observed genetic processes: interspecific hybridization and increased inbreeding occur against the background of a new wave of wolf fighting in Karelia. This region is of importance in the biogeographic sense - through this territory, the animal populations living in Scandinavia are connected to the Russian Plain, and further to Siberia.