HLA-A allele frequency and haplotype distribution in the Dravidian tribal communities of South India

BACKGROUND: The tribal communities of South India are considered to be the original inhabitants of the Indian subcontinent, belonging to the most primitive Dravidian speaking communities. These Dravidian speaking forest dwelling tribal populations have remained isolated from any intermingling with other non-tribal communities. AIMS AND OBJECTIVES: We propose to understand the evolutionary processes mediated by molecular, functional and immunological information based on human leukocyte antigen (HLA) genetic system. MATERIAL AND METHODS: The HLA-A diversity was analyzed in seven Dravidian tribal populations namely Malapandaram, Paniya, Kurichiya, Kanikkar, Adiya, Kattunaikka and Kuruma of Kerala, South India using the PCR-SSP method. The tribal communities were compared with a group comprising of random non-tribal Dravidian samples of southern India. RESULTS: In the present study, 11 HLA-A alleles were identified in the South Indian population. The most frequent alleles included HLA-A*24, A*02, A*33 and *A11. HLA-A*24 had the highest frequency in all the tribal groups while, A*02 was the highest frequency allele in the RND group. The haplotype Cw*14-A*24 was present in all the populations. The three-locus haplotype B*52-Cw*14-A*24 was observed in all the populations except Kurichiya and Kanikkar. CONCLUSION: The study suggests that the RND population is highly diverse and more likely to have an admixed origin.