Genetics and archaeogenetics of South Asia

Genetics and archaeogenetics of South Asia is the study of the genetics and archaeogenetics of the ethnic groups of South Asia. It aims at uncovering these groups' genetic histories. The geographic position of South Asia makes its biodiversity important for the study of the early dispersal of anatomically modern humans across Asia. Based on mitochondrial DNA (mtDNA) variations, genetic unity across various South Asian subpopulations have shown that most of the ancestral nodes of the phylogenetic tree of all the mtDNA types originated in South Asia. Conclusions of studies based on Y chromosome variation and autosomal DNA variation have been varied. Modern South Asians are descendants of a combination of an indigenous South Asian component (termed Ancient Ancestral South Indians, short "AASI"), closest to Southern Indian tribal groups and distantly related to the Andamanese peoples, as well as to East Asian people and Aboriginal Australians, and later-arriving West-Eurasian (Western steppe herders/West Asian-related) and additional East/Southeast Asian components respectively. The AASI type ancestry is found at the highest levels among certain Southern Indian tribal groups, such as the Paniya or Irula, and is generally found throughout all South Asian ethnic groups in varying degrees. The AASI ancestry is hypothesized to be the ancestry of the very first hunter gatherers and peoples of South Asia, before the later groups arrived. Using a proxy or simulated data for the AASI, it was found that the AASI are distinct from Western Eurasian groups and have a relative stronger connection to Andamanese Onge and East Asian peoples (East Eurasians). The West Eurasian ancestry, specifically an Iranian-related component, combined with varying degrees of AASI ancestry, formed the Indus Periphery Cline around ~5400–3700 BCE, the main ancestry of most modern South Asian groups.