The Relevance of HLA Sequencing in Population Genetics Studies
Figure 2
Distributions of the number of nucleotide differences between pairs of sequences (mismatch distributions) in two Asiatic populations of close sample sizes, one Taiwanese (Ami, , top) and one continental (Uyghur, , bottom), based on DNA sequences of HLA-A, HLA-B, and HLA-DRB1 alleles defined at high resolution (sequences downloaded from IMGT/HLA database). While the distributions exhibit a likely unimodal shape for the Uyghur, suggesting recent demographic expansion, they are very irregular for the Ami, reflecting population stationarity or contraction (note that the zero class corresponds to identical sequences, reflecting a high proportion of homozygosity). Besides these demographic signatures, Tajima’s are positive for all distributions, in agreement with balancing selection acting on these loci (not shown).
