Overview
R1a-CTS6 is one of the most significant downstream branches of R1a-L657 and represents a core paternal lineage of Indo-Aryan populations in the Indian subcontinent. Its emergence dates to the early Iron Age, during a period of linguistic diversification and the formation of regional Indo-Aryan societies. Archaeological correlations place CTS6-bearing populations in northern India and Pakistan, where they contributed to early Vedic and post-Vedic cultural traditions. CTS6 underwent extensive diversification during the early historic and medieval periods. Many of its subbranches correspond to regional expansions into the Indo-Gangetic plains, the Himalayan foothills, Punjab and northwestern India. Founder effects within specific caste, clan and tribal communities are evident across multiple downstream clades. The lineage forms a major paternal backbone for numerous Indo-Aryan speaking populations and provides high-resolution insight into ancient demographic structures across northern South Asia.