- Oct 30, 2021
Most Indian communities trace their origin back along the male ‘gothra’ or clan, which is often the basis of endogamous marriage networks. It is notable that the gothra system exists in caste as well as in tribal populations. The majority of Y gene pool of South Asia contains haplogroups C, H, J, R1a, R2, L, and O2a. The high STR variance and widespread nature in Indian subcontinent of haplogroups C5, F*, H, R2 and L1 has usually been considered of indicative to their indigenous origins in the subcontinent. A few studies have suggested haplogroup R1a, with its wide geographic spread including Eastern Europe and Central Asia, as a potential marker of the Indo-Aryan invasion that introduced the caste system to India, as the frequency of this haplogroup was found to be specifically higher among the caste groups. Several other papers, however, have argued against such a simple, essentially single alpha-male lineage initiated migration scenario, which receives no significant support from the maternally-inherited gene tree. The higher variance of STRs in the Indian R1a lineages as compared to those from Central Asia further weakens such a scenario, implying a strong founder effect. However, the current lack of sufficient SNP marker resolution makes it difficult to infer the geographic origin of haplogroup R1a.