Complete mitochondrial DNA sequence tries to settle hitherto putative history of Kayastha population of India.

Abstract

Indian caste system is unique as it has an inimitable type of class system where the social ordering is done based on birth. Within the caste system, there is a distinct endogamous population known as the Kayastha, who have had inconclusive stratification records due to unidentified historical records. To gain a more inclusive view on the history and genetic affinities of Kayastha people, complete mitochondrial genomes from 15 individuals of a Kayastha population from North-western India have been sequenced. Interestingly, three novel sub-clades (U2b2a, M3d2, and M33a3b) have been identified that represent unique Kayastha motifs. The haplotype-based analysis suggests that the Kayastha population shares genetic affinities with the Indo-European and Sino-Tibetan populations found in the trans-Himalayan region. The FST based population comparison and the MDS plot indicates that Kayastha people have close maternal genetic affinity with the available genetic database of Brahmins, Kashmiris, and Tharus. The maternal genetic lineages among Kayastha population shows deep in situ origin that emerged much before settled life developed on this sub-continent. Both mtDNA and Y-chromosome markers, trace the genetic lineages of Kayastha population with Tharus, who regard themselves Kshatriya, corroborated by the oral history of the Kayasthas for their Kshatriya affiliation. It also validates genetic heritage of earliest settlers of India in both indigenous tribal and caste populations.