Analysis of HLA-DRB1 polymorphism in the Gidra of Papua New Guinea.

The genetic structure of the Gidra-speaking population inhabiting 13 villages in Papua New Guinea was investigated, based on the analysis of HLA-DRB1 polymorphism. Nei's fixation indices (F(IS), F(IT), and F(ST)) showed that the Gidra villages were genetically differentiated. The genetic distances significantly correlated with the geographic distances among the 13 villages. Thus, it is likely that a low intervillage migration rate has been maintained since the Gidra community was established. Correspondence analysis revealed that the Gidra, who belong to non-Austronesian-speaking groups, are genetically located at the intermediate point between the Aboriginal Australian groups and the Austronesian-speaking groups. Moreover, the HLA-DRB1*0802 allele, which has been observed in only two Polynesian groups (Austronesian-speaking groups) of Oceanian populations, was also found in the Gidra. These results suggest that the admixture of Austronesian and indigenous non-Austronesian groups beyond the linguistic boundary occurred partly in Papua New Guinea before Austronesian groups spread to the Pacific.