Study on the haplotypes of MICA and MICB microsatellite and HLA-B locus in the Guangzhou Han population

The purpose of this study was to investigate the genetic polymorphisms and haplotypes of microsatellite locus in exon 5 of the MICA gene and intron 1 of the MICB gene and human leukocyte antigen-B (HLA-B) gene based on 106 samples of the Guangzhou Han population through means of polymerase chain reaction and the fluorescent technique (6-FAM). The corresponding haplotype frequencies, linkage disequilibrium values and relative linkage disequilibrium values were estimated based on population data. The results show that the genotype distributions of MICA and MICB microsatellite and HLA-B satisfy the Hardy-Weinberg equilibrium. In total, five alleles of MICA microsatellite locus and 14 alleles of MICB microsatellite locus were observed. MICA A5 was the most common allele (0.2877), whereas A4 was the least common (0.1321). MICB CA14 was the most common allele (0.3255), and CA19 and CA28 were the two least common (0.0047). CA27 was not observed at all. Five kinds of MICA-MICB haplotypes, 18 kinds of MICA-HLA-B haplotypes and 12 kinds of MICB-HLA-B haplotypes occurred at frequencies of more than 1%. The common haplotypes of MICA-MICB, MICA-HLA-B and MICB-HLA-B were A5-CA14, A5.1-CA18, A4-CA26, A9-CA15, A5-B*15(62), A5.1-B*1301/1302, A4-B*1301/1302, A6-B*51, A6-B*4403, A9-B*3802, CA14-B*4601, CA18-B*1301/1302 and CA26-B*1301/1302, and these haplotypes showed strong linkage disequilibrium. The polymorphisms and haplotype distributions of MICA and MICB microsatellite and HLA-B locus in the Guangzhou Han population have their own distinct genetic characteristics. The microsatellite locus of exon 5 of the MICA gene and intron 1 of the MICB gene could therefore be used as genetic markers in the studies of anthropology, gene linkage analysis in genetic diseases, individual identification and paternity testing in forensic medicine.