, similarly, conclude that ANI and ASI were formed in the 2nd millennium BCE. They were preceded by a mixture of AASI (ancient ancestral south Indian, i.e. hunter-gatherers sharing a distant root with the Andamanese, Australian Aboriginals, and East Asians); and Iranian agriculturalists who arrived in India ca. 4700–3000 BCE, and "must have reached the Indus Valley by the 4th millennium BCE". According to Narasimhan et al., this mixed population, which probably was native to the Indus Valley Civilisation, "contributed in large proportions to both the ANI and ASI", which took shape during the 2nd millennium BCE. ANI formed out of a mixture of ""Indus Periphery"-related groups" and migrants from the steppe, while ASI was formed out of ""Indus Periphery"-related groups" who moved south and mixed further with local hunter-gatherers. The ancestry of the ASI population is suggested to have averaged about 73% from the AASI and 27% from Iranian-related farmers. Narasimhan et al. observe that samples from the Indus periphery group are always mixes of the same two proximal sources of AASI and Iranian agriculturalist-related ancestry; with "one of the Indus Periphery individuals having ~42% AASI ancestry and the other two individuals having ~14-18% AASI ancestry" (with the remainder of their ancestry being from the Iranian agriculturalist-related population). The authors propose that the AASI indigenous hunter-gatherers represent a divergent branch that split off around the same time that East Asian, Onge (Andamanese) and Australian Aboriginal ancestors separated from each other. It inferred, "essentially all the ancestry of present-day eastern and southern Asians (prior to West Eurasian-related admixture in southern Asians) derives from a single eastward spread, which gave rise in a short span of time to the lineages leading to AASI, East Asians, Onge, and Australians.