For each species the number of allotypes analyzed for each MHC class I gene is tabulated at the top of the figure. Ap under orangutan is the orangutan pseudogene orthologous to HLA-A; I under the macaques is a macaque specific MHC-B-related gene. The different sequence motifs at positions 76-83 are given at the left and organized according to whether they have a Bw4, Bw6, C1, or C2 motif. For our purpose, any motif that is not Bw4, C1, or C2 is defined as Bw6. On the right, boxes with black shading denote the genes that encode each sequence motif, and the number of allotypes having the motif are given in white within each black box. Only motifs that were observed in at least 5% of allotypes in at least one species are shown.