Reciprocal hybridization between white-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) in western Canada: evidence from serum albumin and mtDNA sequences

Abstract

The extent and direction of hybridization between white-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) in western Canada were investigated by two genetic approaches, protein electrophoresis and DNA sequencing. Species-specific allelic variants at the serum albumin locus were examined for 25 white-tailed deer and 30 mule deer from 24 localities. The two species were essentially fixed for alternate alleles; one mule deer was heterozygous. The polymerase chain reaction was used to amplify a 359 base-pair portion of the mitochondrial cytochrome b gene from these same animals. DNA sequencing revealed 10 variable nucleotide positions that define nine mtDNA sequence genotypes. Two deer were anomalous. The mule deer that was an albumin heterozygote had an mtDNA genotype otherwise confined to the white-tailed deer. This suggests that the animal has a white-tailed female and a mule deer male as ancestors. One white-tailed deer, which had the expected albumin genotype, had a sequence genotype that is otherwise found only in O. hemionus elsewhere in North America. This animal appears to be a backcross or later generation hybrid. Hybridization between deer species in western Canada has resulted in a low level of reciprocal genetic introgression.