Characterization of Mhc-DRB allelic diversity in white-tailed deer (Odocoileus virginianus) provides insight into Mhc-DRB allelic evolution within Cervidae

Although white-tailed deer (Odocoileus virginianus) are one of North Americ a's best studied mammals, no information is available concerning allelic di versity at any locus of the major histocompatibility complex in this taxon. Using the polymerase chain reaction, single-stranded conformation polymorp hism analysis, and DNA sequencing techniques, 15 DRB exon 2 alleles were id entified among 150 white-tailed deer from a single population in southeaste rn Oklahoma. These alleles represent a single locus and exhibit a high degr ee of nucleotide and amino acid polymorphism, with most amino acid variatio n occurring at positions forming the peptide binding sites. Furthermore, tw enty-seven amino acid residues unique to white-tailed deer DRB alleles were detected, with 19 of these occurring at residues forming contact points of the peptide binding region. Significantly higher rates of nonsynonymous th an synonymous substitutions were detected among these DRB alleles. In contr ast to other studies of Artiodactyla DRB sequences, interallelic recombinat ion does not appear to be playing a significant role in the generation of a llelic diversity at this locus in white-tailed deer. To examine evolution o f white-tailed deer (Odvi-DRB) alleles within Cervidae, we performed a phyl ogenetic analysis of all published red deer (Ceel-DRB), roe deer (Caca-DRB) , and moose (Alal-DRB) DRB alleles. The phylogenetic tree clearly shows a t rans-species persistence of DRB lineages among these taxa. Moreover, this p hylogenetic tree provides insight into evolution of DRB allelic lineages wi thin Cervidae and may aid in assignment of red deer DRB alleles to specific loci.