Comprehensive research on the distribution of HLA-DRB1 in Chinese populations

By presenting antigen peptides, HLA-DRB1 plays an important role in the immune system. However, the allele frequency of HLA-DRB1 exon 2 across China has not been comprehensively studied, especially in minority populations. We sampled 3757 individuals from 59 population. The HLA-DRB1 region from 212 to 463 bp (NM_002124.4 exon 2) in each population was sequenced by Sanger sequencing and genotyped via SBTengine® software, and the allele frequency was calculated by GenAlEx 6.5. Eighty-two DRB1 alleles were identified. The expected heterozygosity of DRB1 was lower in the south than in the north, which was inconsistent with the Y chromosome and mitochondrial DNA results. The Mantel test and nonparametric correlation analysis showed that the correlations of the genetic distance with geographical distance and of DRB1 allele frequencies with latitude weakened after the southern and northern groups were considered separately. Principal coordinate analysis showed that populations speaking the same languages were not codistributed. Compared with other genetic markers, the distribution of DRB1 seems less affected by geographic distance and ethnic origin. Local factors such as gene flow with neighbouring populations, geographic isolation or natural selection are important forces shaping the DRB1 gene pool of local populations.