DNA Mutation

25 Sep 2017

Chris Gatling in Current World Archaeology 85 (October 2017) www.world-archaeology.com ... page 85 ... looks at human DNA mutation. People argued that modern humans evolved 100,000 years ago and move Out of Africa 60,000 years ago - reaching Australia 40,000 years ago. Martine James in Molecule Hunt, raised the ante to 150,000 years ago, and Clive Gamble in Timewalkers was in favour of 200,000 years ago. He said humans reached Australia 80,000 years ago - which turns out to be a pretty good prediction - on current evidence. Others of course dismiss the idea of using dates based on DNA mutation rates as it is theoretical, based on a small amount of sample, and the sampling technique was not necessary good in practise. Catling adds, trusting in the rate of mutation being constant is also open to doubt. However, in recent months, he adds, SNA samplings and dating techniques have improved dramatically, not least in the ability to extract and replicate ancient DNA - distinct from working backwards from modern DNA. Human remains from a cave in Ethiopia have pushed back modern human origins to 195,000 years ago and in Morocco at 286,000 years ago (using thermoluminescence on burnt flint tools, a method once restricted to pottery sherds). The tools were manufactured by the Levellois technique of flint knapping - thought to be a signal of modern humans (but may not be). I haven't read much about doubts concerning thermoluminescence but it may be a method waiting for some problems. Catling makes the point that so far most evidence of early humans comes from the African Rift Valley - which is where the research into human origins has mainly taken place. In other words, human origins could be elsewhere in Africa - once people look for the evidence. Dor instance, we now have a skull from South Africa dated 260,000 years ago that was previously compartmentalised as archaic H. sapiens - but is it due to re-evaluation as fully Homo sapiens.

To add some mischief, Chris Stringer of the National History Museum in London says Neanderthals split from the human line at least 500,000 years ago. Should this date mark the origins of other groups too. In other words, when considering human origins the best rule of thumb is to take the most distant date suggested by the data and then assume it is an underestimate. Good point by Stringer. We might ask, do modern humans go back 500,000 years? However, the Out of Africa has been heavily politicised since its inception - as a way of providing moral support to multi-culturist social engineering. The fact the time line has to be constantly revised backwards is a reflection of reality that once again shows combining science with politics creates problems for science - but not for politics. Why would anyone think there was a pristine origin for modern humans, divorced from all the humans that preceded them. It is the idea that all humans have one special moment, when we ceased to be proto humans and became modern humans, that is at the heart of the propaganda - and DNA research is making a mockery of the idea.