HLA class II gene polymorphism in Parsees and Zoroastrians of Iran

Extensive polymorphism of the HLA genes in different ethnic groups has been used as an invaluable tool for anthropological studies. In this study, HLA-DRB1, DQA1 and DQB1 allele frequencies and haplotypes were determined in 72 Parsees and 65 Zoroastrians living in Iran. The predominant DRB1 allele was *1103 = 4 in Parsees and *0701 in Zoroastrians. DQA1*0501 was the most common alleles in both populations. The most frequent DQB1 allele was *0301 in Parsees and *0201 in Zoroastrians. DRBI*1103 = 4-DQA1*0501-DQB1*0301 and DRB1*0701-DQA1*0201-DQB1*0201 were the most prevalent haplotypes in Parsees and Zoroastrians, respectively, Significant deviation from Hardy-Weinberg equilibrium was observed in DQA1 and DQB1 loci of Zoroastrians. The former locus also departed from neutrality due to balancing selection. All pairs of the studied loci in this study showed significant linkage disequilibrium. Analysis of molecular variance indicated that the main variation was confined to individuals within the studied populations. Neighbour-joining tree based on Nei's genetic distances according to DRB1 and DQB1 allele frequencies showed that Parsees and Zoroastrians of Iran were located in the same cluster of the phylogenetic tree. Furthermore, Zoroastrians of Iran and Pakistan are very close to each other. This stud), will serve as a reference for further anthropological studies when the HLA profile of all ethnic groups of Iran is investigated.