Out of Africa

23 Sep 2010

At www.bbc.co.uk/news/science_environment-11327442?print=true Sept 2Ist ... geneticists have estimated the the Out of Africa human migration to SE Asia and Australia took place around 60,000 years ago. However, stone tools found in Arabia and India recently point to an earlier date, possibly around 80,000 years ago. Michael Petraglia of Oxford University is even thinking in terms of multiple population movements Out of Africa possibly from as early as 120,000 years ago - towards the end of the last Interglacial period. Stone tool caches have been found most recently in the desert of Arabia in an area far from the sea so the idea is now being toyed with that Out of Africa migrations were primarily land based movements by people simply walking rather than coastal movements along the sea shore. Boats have been dropped from the equation. They are difficult to locate archaeologically as they are generally made of wood which is biodegradeable and disappears over the course of time. Hence, the next best course of action - ignore the boats. Absence of evidence is evidence of absence. Chris Stringer of the Natural History Museum and constantly quoted after writing his book, Homo Britannicus, a real treasure trove of information, is sticking to the genetic data as he sees science as more reliable than the archaeology - which is geographically spread out and from indeterminate sources in many instances. Tools themselves do not come with an ethnic marker and they could belong to a group that have since died out. This is where the genetic studies go wrong, Petraglia counters. They are based on modern population samples. There is an absence of ancient DNA to test. In other words, both prognositications have problems which the advocates of each wish to downplay. There will be further developments - we can be sure of that.