Inheritance of Signs of Parent Species by Hybrids of Russet, Yellow, and Speckled Ground Squirrels (Spermophilus, Sciuridae, Rodentia)

The inheritance of the size, color, and bioacoustic characteristics of russet (Spermophilus major), yellow (S. fulvus), and speckled (S. suslicus) ground squirrels in hybrids differing in their genetic status was studied. In a hybrid population of russet and yellow ground squirrels, ten individuals of S. major, ten individuals of S. fulvus, and 40 hybrids of S. major × S. fulvus were analyzed; in a hybrid population of russet and speckled ground squirrels, eleven individuals of S. major, eleven individuals of S. suslicus, and 24 hybrids of S. major × S. suslicus were analyzed. Hybrid individuals that are different in genetic status have been shown to demonstrate differentiation in the vector space of the variability range of the parental species. At the same time, both a shift in some categories of hybrids towards one of the hybridizing species and a significant deviation are noted. The results indicate an increase in the level of variability in size, color, and bioacoustic characters in hybrid populations associated with the erosion of the divergent hiatus of specific features of the parental forms due to the formation of a differentiated hybrid population. As hybrid individuals with different combinations of parental traits accumulate in the population, the situation arises in which a sufficient number of hybrids with an overall combination of parental traits (Hcomb) appear in this population. Such hybrid individuals have different combinations of species-specific markers in the homozygous state in their genotypes. In the hybrid population of the russet and yellow ground squirrels, the proportion of such hybrids, according to our data, is 22.5% (n = 40), and in the hybrid population of the russet and speckled ground squirrels, it is 12.5% (n = 24). This category of hybrid individuals can be considered as possible material for further microevolutionary events and the process of speciation.