HLA Class II (DRB1 and DQB1) Polymorphism in Omanis

The HLA class II polymorphism of 254 healthy unrelated Omanis was analyzed by PCR-SSP method, and the detected frequencies were compared to those reported in 20 other populations. The most frequent HLA class II DRB1 alleles were DRB1*16, DRB1*03 and DRB1*15 with frequencies of 0.315, 0.224 and 0.106 respectively, while the most frequent DQB1 alleles were DQB1*05 and DQB1*02 with frequencies of 0.366 and 0.283 respectively. The haplotype analysis revealed that DRB1*03-DQB1*02 was the most common HLA class II haplotype with linkage disequilibrium (a frequency of 0.206). Compared with other populations, our result, deduced from the analysis of genetic distances and the construction of neighbour joining dendrogram, indicates that Omanis are related to Mediterranean and West-Asian populations. This fact might be explained by several historic and socio-geographic factors if we consider on the long history of this population.