HLA AFFINITIES OF IYERS, A BRAHMIN POPULATION OF TAMIL-NADU, SOUTH-INDIA

Seventy-four randomly sampled Iyers, a Brahmin population of Tamil Nad u and preachers and followers of the Advaita philosophy, living in Mad urai, were studied for their HLA-A, HLA-B, HLA-C, HLA-DR, HLA-DQ, C4A, C4B, and BF polymorphisms and compared with other populations. HLA al leles A1, A11.1, A24, A33, B35, B44, B51, B52, B57, Cw4, Cw6, Cw7, DR4 , DR7, DR8, DR10, DR11, DR15, and DQ1 and C4A3, C4A*4, C4A*6, C4A*Q0, C4B1, and BF*S were represented in 15% of the samples studied. HLA a lleles A25, A69, Cw3, Cw8, B45, B14, B39, B18, B50, and B56 were not i dentified. Various populations of Tamil Nadu were compared, but the Iy ers of Madurai formed a separate cluster with Sourashtrans of Madurai and major group 4 (various Brahmin populations of Tamil Nadu); hill tr ibes (Irulas, Malayalis, and Badagas) and caste groups in the plains ( Kallars and Nadars) formed distinct clusters. Comparison of the Iyers with other Indian and world populations revealed that Iyers form a dis tinct branch of the Indo-European and Central Asian tree. The Bhargava s of Lucknow, another Brahmin caste group from Uttar Pradesh, did not cluster with the Iyers but clustered with Central Asian populations. T he Punjabis of Delhi clustered with European and Middle Eastern popula tions. Studies on two-locus haplotypes of Iyers revealed unique haplot ypes in them (A26-B8, A33-B44, A33-Cw7, A1-B57, B8-DR3, B44-DR7, DR7-D Q2, C4A32-C4B*Q0, and C4A*6-C4B*2), most of which were not identified in the Bhargavas of Lucknow and the Punjabis of Delhi. Thus it is pos sible that various Brahmin populations of India differ in their origin , migration, and settlement, although all of them adopted Hinduism in ancient times. A comparison of haplotypes in Iyers with the world popu lation reveals a sharing of haplotypes with Southeast Asian population s. This implies that the ancestors of the Iyers of Madurai, who origin ated in the Eurasian steppes or Central Asia, might have migrated to I ndia through Southeast Asia, thus developing the prevalent haplotypes en route.