South Asian Maternal Lineage haplogroup R30 Provides Phylogenetic Evidence of human dispersal across South Asia

South Asia is central to debates on early human dispersals, particularly the Out of Africa model and Eurasian colonization. Studies of M haplogroups have been used to support both Northern and Southern route hypotheses, but current archaeological and genetic evidence in the region remains contradictory. In the present work, we find that in addition to haplogroup M lineages, a few R lineages exhibit ancient, locally rooted variation, with R30 being one of the widespread haplogroup of R lineages across South Asia. To better understand South Asian demographic history, we investigated the phylogeographic distribution of haplogroup R30, an indigenous lineage. We used 190 complete modern and ancient sequences from diverse mainland and island populations including incorporation of 44 newly generated sequences which enabled the refinement of the R30 phylogeny and the identification of a novel basal lineage, R30c. Bayesian and {rho}-based age estimates suggest that R30 originated in the Indian subcontinent ~50 kya. Early diversification likely occurred in Northern India, giving rise to R30b (~44 kya), while R30a and R30c differentiated primarily in Southern India. Several subclades of haplogroup R30 exhibit strong signatures of founder effects, particularly among the language isolate Vedda of Sri Lanka, Uru Kurumban of Southern India, and the populations of the Lakshadweep archipelago. Bayesian skyline analyses indicate long-term demographic stability followed by rapid lineage expansion ~20 kya and more recent declines consistent with localised drift and relatively recent founder events. The presence of early-diverging R30 lineages in Thailand and Indonesia further supports long-term connections between South and Southeast Asia. Overall, archaeological and genetic evidence point towards the multiple migrations for South Asia colonizations.