Denisovans and India

7 Aug 2013

At ... is a discussion of a paper by Sheila Mishra et al which centres on the introduction of micro blade tool assemblages in India, and their possible association with an actual human migration, focussing on one site in particular in Madhya Pradesh (and now dated around 45,000 years ago). John Hawks is his usual sceptical self and uses it to discuss the Late Pleistocene in India. The sub continent is an interesting location as it is intermediate between Africa and Australia - and the latter was colonised by modern humans as early as 50,000 years ago - if not earlier. There is supposed to bhe a direct link between microliths in India and others in southern Africa - and is thought that early humans expanded by following the coast line (which is generally thought not to have been much different to what it is today). The idea the equator may have been located skew whiff from what it is now is not part of current thinking - but some interesting points are raised in this blog piece.

Hawks claims none of the arguing anthropologists has considered the Denisova genome and how it ties in whith the dispersal of humans across South Asia. He says that Melanesians and Australian Aborigines have substantial Denisova ancestry - whereas south and south east Asians, and the people of Java, Sumatra and Borneo have traces of Denisova ancestry. Hence, there must have been more than one wave of migration into SE Asia. The later wave (or waves) occurred afte the initial spread of people that had colonised Australia and Melanesia (which makes sense). The later wave, or waves, must also have made up the vast majority of SE Asian ancestry which might also include various hunter gatherer tribes such as the Andaman Islanders. Their exodus Out of Africa could well have been fairly late in the Pleistocene and long after the dispersal of Melanesians and Aborigines. 

John Hawks suggests the Denisovans lived in what is now China before being overwhelmed by later waves of migration (from wherever). Denisovans would also have lived in India and SE Asia. Mishra, conversing with Hawks, differs from the usual routes of migration long the shores of southern Asia (Arabia, India, Thailand etc) suggests they migrated across the northern tie of South Asia (southern Siberia and China). This would fit in with the discovery of Denisovans in central Asia and the idea the Late Pleistocene had a different equator and poles positions. The savannah zone in the Late Pleistocene appears to have stretched from Iberia in the west to the extremes of NE Asia and Alaska (including what is now the submerged Bering Straits). This would imply the Denisovans, and therefore the Melanesians, migrated south of the savannah, or along its borders. Hawks seems to say that technological innovations (such as the microblade tool assemblages) do not necessarily coincide with the arrival of new people. He uses similarities between the culture of Neanderthals in Europe and people inhabiting southern Africa - and yet no trace of the Neanderthal genome has been found there.