title: The Adaptive Change of HLA-DRB1 Allele Frequencies Caused by Natural Selection in a Mongolian Population That Migrated to the South of China.
abstract: Pathogen-driven balancing selection determines the richness of human leukocyte antigen (HLA) alleles. Changes in the pathogen spectrum may cause corresponding changes in HLA loci. Approximately 700 years ago, a Mongolian population moved from the north of China to the Yunnan region in the south of China. The pathogen spectrum in the south of China differs from that in the north. In this study, changes in the HLA genes in the Yunnan Mongolian population, as well as the underlying mechanism, were investigated. A sequence-based typing method (SBT) was used to genotype HLA-DRB1 in 470 individuals from two Mongolian populations and another five ethnic groups. Meanwhile, 10 autosomal short tandem repeats (STRs) were genotyped to assess the influence of genetic background on HLA-DRB1 frequencies. The frequencies of certain alleles changed significantly in the Mongolian population that migrated to Yunnan. For example, DRB1*12:02:01 increased from 6.1% to 35.4%. STR analysis excluded the possibility of a recent bottleneck and indicated that 50% of the genetic consistency between northern and southern Mongolians; Tajima's D value for HLA-DRB1 exon2 and dN/dS analysis showed that the HLA-DRB1 genes in both Mongolian populations were under balancing selection. However, the sites under natural selection changed. We proposed that the dramatically change of HLA frequencies in southern Mongolian was caused by a combination of inter-population gene flow and natural selection. Certain diseases specific to the south of China, such as malaria, may be the driving force behind the enhanced DRB1*12:02:01 frequency.
authors.affiliation: Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming 650118, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Sun
authors.affiliation: Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming 650118, China.
authors.forename: Zhaoqing
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming 650118, China.
authors.forename: Keqin
authors.initials: K
authors.lastname: Lin
authors.affiliation: Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming 650118, China.
authors.forename: Shuyuan
authors.initials: S
authors.lastname: Liu
authors.affiliation: Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming 650118, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Huang
authors.affiliation: Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming 650118, China.
authors.forename: Xiuyun
authors.initials: X
authors.lastname: Wang
authors.affiliation: Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming 650118, China.
authors.forename: Jiayou
authors.initials: J
authors.lastname: Chu
authors.affiliation: Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming 650118, China.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Huang
mesh_terms: D002681:China; D005787:Gene Frequency; D059811:HLA-DRB1 Chains / Q000235:genetics*; D006801:Humans; D018895:Microsatellite Repeats; D008986:Mongolia; D012641:Selection, Genetic
chemical_list: D059811:HLA-DRB1 Chains