Figure 1.

Frequency distribution of numbers of pairwise nucleotide differences in primate MHC class I sequences. The frequency histogram was obtained from all possible pairwise comparisons of full-length sequences between 50 HLA-A, -B, and -C alleles, 25 chimpanzee (Pan troglodytes) Patr-A, Patr-B, and Patr-C alleles, 20 rhesus monkey (Macaca mulatta) Mamu-A and Mamu-B alleles, 15 non-Callitrichinae New World primate sequences, and 22 Callitrichinae sequences. Distribution of inter- and intralocus nucleotide differences in human are indicated. NWP, New World primate.