Hybridization between the European and Asian badgers ( Meles , Carnivora) in the Volga-Kama region, revealed by analyses of maternally, paternally and biparentally inherited genes

Two closely related species of Meles (Carnivora), the European badger ( M. meles ) and the Asian badger ( M. leucurus ), are distributed allopatrically in continental Eurasia but show a narrow contact zone around the Volga and Kama Rivers, Russia. We analyzed maternally (mitochondrial DNA), paternally ( SRY gene and CAN-SINEs on the Y chromosome), and biparentally ( CFTR gene and nine microsatellite loci) inherited genes for evidence of hybridization between the two species in the contact zone. Of 71 badgers examined, we identified 17 individuals as hybrids with mixed genotypes for the first time. Some hybrids appeared to have resulted from repeated backcrossing with the parental species. In addition, the hybridization was symmetric between the two species. Compared with previous palaeontological data, the hybridization between the two species could have resulted from secondary contact due to western expansion in distribution by the Asian badgers.