Migration across the Wallace Line

11 June 2022
Ancient history

At https://phys.org/news/2022-06-pre-historic-wallacea-pot-human-genetic.html … the gist of this story is that hunter-gatherer genes have just about disappeared, possibly because of the long elapse of time since they were the dominant group in Wallacea. The genes of newcomers appear to dominate genetic results even though it is clear mixing between the newcomers and the indigenous occupants east of the Wallace Line did occur. It’s a bit like the dilution of the genetic content of Neanderthals in what are regarded as modern humans, virtually one group of people replacing another lot of people, across a geographical span that included most of western Asia and Europe. Logic would imply something else was going on.

It is not too surprising that the arrival of farmers from Indonesia and SE Asia led to them dominating the genetic heritage, as they provide for more children than a hunter-gatherer could. However, it is the dates of these migrations across the Wallace Line that are intriguing. They appear to begin around 3000BC, which was a global turndown and period of migration. It continued intermittently through to 1500BC, and later. The dates coincide with climatic downturns and the possibility of catastrophic events setting this in motion – on a global scale. Another interesting date, as far as 3000BC, is that this coincides with the arrival of newcomers in northern Australia. They did not make the same sort of impact as they did in Indonesia, shifting to a farming economy, for example, but the fact that their arrival occurred at this time is thought provoking. West of the Wallace Line lies most of Indonesia, and east of the line is Sulawesi, New Guinea, Timor, Australia, etc. The study is published in Nature journal https://www.nature.com/articles/s41559-022-01775-2

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