Taxonomy and Phylogeny of Sibling-Species Sicista of the Group Caucasica and Their Position in the Genus Sicista (Rodentia, Dipodoidea) according to Sequencing of the IRBP Gene Fragment of Nuclear DNA

Abstract

To specificate phylogenetic relationships between sibling-species Sicista of the caucasica group and to determine their position in the genus Sicista, comparative analysis of the nucleotide sequences of a fragment (903 bp) of the first exon of the IRBP (interphotoreceptor retinoid-binding protein) gene of nuclear DNA has been carried out for three Sicista species (S. caucasica, S. kluchorica, and S. kazbegica) of the caucasica group. Some other Sicista species (S. concolor, S. tianschanica, and Sicista species of the groups betulina and subtilis) have been taken for comparison. The results reflect the monophyly of the group and its division into the three clades corresponding to sibling-species of the group. It has been shown that the average genetic distances between S. caucasica and S. kluchorica calculated on the nucleotide sequences of a fragment (903 bp) of the first exon of IRBP gene using three-parametrical Tamura’s model (T92) do not exceed 0.4%. The level of differences of each of these two species from S. kazbegica is 0.7%, which is comparable to the interspecific genetic distances for Sicista sibling-species of the group betulina (intergroup genetic distances exceed 2%).