Fig. 2: Papa-B allele counts, frequencies, and allotype phenotypes at 12 study sites.

For each Papa-B allele, it is noted which peptide-binding supertype that it possesses (B27 (yellow), B07 (blue), Patr-B*17:03 (17:03, brown), and whether or not it encodes a KIR epitope (either Bw4 (green) or C1 (red)). ^aKIR epitope and supertype are “Unknown.” ^bGenotyping resolved the second allele as being one of three alleles (Papa-B*01:02, 04:01, 09:02), all of which have the B07 supertype and lack a KIR epitope. ^cFor five eastern bonobos, a second Papa-B allele could not be identified. ^dAsterisks indicate significant frequency differences between bonobo populations west and east of the Lomami River (two-tailed Fisher’s exact tests, p < 0.0001; all comparisons in Supplementary Table 5). ^eB07 phenotype distributions for each population are given in Supplementary Table 2.