Varanasi: A genetic study by researchers from Banaras Hindu University (BHU) and four other institutions has identified a possible genetic factor behind the unusually high prevalence of tuberculosis (TB) in the Sahariya tribe of Madhya Pradesh. The findings were published recently in the international journal Mitochondrion. The Sahariyas, recognised as a Particularly Vulnerable Tribal Group (PVTG), record TB rates ranging from 1,518 to 3,294 cases per one lakh population—many times higher than the national average. The study, led by Prof. Gyaneshwer Chaubey of BHU, analysed mitochondrial genomes of 729 individuals, including 140 Sahariyas and 589 from neighbouring tribes and castes, to probe maternal genetic lineage and its role in TB susceptibility. Researchers found that the Sahariya tribe carries two rare maternal haplogroups—N5 and X2—that are completely absent in neighbouring populations. Phylogenetic studies suggest these lineages entered the tribe from western India during the early Iron Age, altering their genomic structure and possibly increasing their vulnerability to TB.”This is the first time a study has explained how a population’s genetic structure interacts with a disease,” Prof. Chaubey said. Lead author Debasruti Das added that understanding genetic susceptibility in vulnerable communities could strengthen public health strategies in India, which bears the world’s largest TB burden.Senior author Prof. Prashant Survajhala noted the findings point to a founder effect, where rare maternal lineages became concentrated in the Sahariya population, potentially affecting immune response to TB. He emphasised that genetic factors, coupled with malnutrition and poor access to healthcare, contribute to the community’s high disease burden.The study, which used high-resolution mitochondrial DNA analysis—including new samples from Vidisha district of Madhya Pradesh—was conducted by researchers from BHU, the University of Calcutta, Forensic Lab Jabalpur, and Jaipur.
