Twelve HLA-DR6-related DRB1 alleles and associated DR, DQ haplotypes in traditional Australians and other populations of Asia-Oceania.

The relative distributions of 12 HLA-DR6-related HLA-DRB1 alleles in indigenous populations of Australia, Melanesia, Polynesia, Micronesia, and northern and southern China have been determined by analysis of nucleotide sequence polymorphisms in 364 examples of HLA-DR6 positive chromosomes. Oligonucleotide hybridizations of polymerase chain reaction products of HLA-DQA1, DQB1, DRB1 and DRB3 genes generated 24 HLA-DR6-related haplotypes. The study aimed to determine the regional distribution of DR,DQ haplotypes associated with three novel HLA-DR6 alleles, namely DRB11408, 1409, and 1410, known to occur in Australian Aborigines, to gain further insights into the molecular phylogeny of these alleles. DRB11408 was the most common HLA-DR6 subtype in Oceania, although it was not detected in Chinese. In Australian Aborigines and Papua New Guinean highlanders, DRB11408 was associated with DRB30202, while in Polynesians and Micronesians it was associated with DRB30101. The different haplotype arrangements, together with the near absence of DRB11408 in coastal Melanesians, suggest the possibility that two independent mutations have generated DRB11408 in Australia and Oceania. DRB11409 and 1410 alleles were confined to Australian Aborigines, while DRB11407 was found exclusively in Melanesians; DRB11401 was the only HLA-DR6 allele represented in all study populations. The population-specific HLA-DR6 alleles and haplotypes have important implications for unrelated bone-marrow donor registries in Australia and Oceania.