Allelic diversity at the major histocompatibility complex class II DP
locus of rhesus macaques was studied by sequencing exon 2 of Mamu-DPA1
and -DPB1 genes. The Mamu-DPA1 gene is apparently invariant, whereas
the Mamu-DPB1 locus displays polymorphism Here we report the character
ization of 1 Mamu-DPA1 and 13 Mamu-DPB1 alleles which were compared wi
th other available primate Mhc-DPA1 and -DPB1 sequences. As compared w
ith Mhc-DRB and -DQB1, most codons for the contact residues in the ant
igen binding site of the primate Mhc-DPB1 gene have a relatively low d
egree of variation in encoding various types of amino acids. In contra
st to Mhc-DRB and -DQB, the HLA- and Mamu-DPB1 sequences cluster in a
species-specific manner in phylogenetic trees. Mhc-DPB1 polymorphisms,
however, are inherited in a transspecies mode of evolution, as is dem
onstrated by the sharing of lineage members between closely related ma
caque species. The data demonstrate that the transspecies character of
Mhc-DPB1 polymorphism was retained over much shorter periods of time
as compared with its sister class II loci, Mhc-DQ and -DR.