The contribution of HLA class I and II alleles and haplotypes to the investigation of the evolutionary history of Tunisians.

The frequencies of HLA class I and class II alleles and haplotypes of 104 healthy unrelated Tunisians were analyzed by high-resolution PCR-reverse dot blot hybridization, and was compared with other Mediterranean and Sub-Saharan Africans using genetic distances measurements, Neighbor-joining dendrograms, correspondence, and extended haplotypes analysis. The most frequent HLA class I A alleles were A02, A24, and A30, while the most frequent B alleles were B44, followed by B50, B51, and B07. Among HLA class II DRB alleles analyzed, the most frequent were DRB10301, DRB10701, DRB11501, followed by DRB11303 and DRB10102; for DQB1, they were DQB10301 and DQB10201. Three-locus haplotype analysis revealed that A03-B07-DRB11503 and A02-B44-DRB10402 were the most common HLA class I and II haplotypes in this population. Compared with other communities, our result indicate that Tunisians are very related to North Africans and Western Europeans, particularly Iberians, and that Tunisians, Algerians, and Moroccans are close to Berbers suggesting little genetic contribution of Arabs who populated the area in 7th to 8th century AD. The similarities and differences between Tunisians and neighboring and related communities in HLA genotype distribution provide basic information for further studies of the MHC heterogeneity among Mediterranean and North African countries, and as reference for further anthropological studies.