Thursday, 3 July 2014

Those Neanderthal Genes

Recently genetic material was recovered from some Neanderthal remains recovered at an archaeological site in Spain. It appears to have caused some excitement among geneticists since it raises some questions and, perhaps, answers others. Increasingly scientists are having to reassess their theories on this branch of humanity. It now begins to look as if they may have been a distinct, and now extinct branch of humanity. Just as there is greater ‘ethnic’ variety between distinct populations in Africa than outside it, there may have been a similar diversity elsewhere with different ‘species’ of humanity developing side by side. 

The common mythology about the Neanderthals is that they were one step in the evolutionary chain that eventually produced modern Homo Sapiens Sapiens. It also says that they were brutish, lacking in any creative skills and barely sapient. Now we know, since the DNA shows it, that they were a completely separate genus of the human family. The archaeologists have also found that Homo Neanderthalis used tools, created some wonderful ‘jewellery’ out of shells and stone beads, had clothing made of hide and even shoes. Hardly total thickos incapable of civilised behaviour.

There is considerable evidence that they indulged in some elaborate ritual behaviour. Their burials show evidence of some form of religious system. That they could organise quite complex activities is evidenced by the fact they hunted some large animals by driving them toward and over cliff faces or into gorges. One of their preferred targets being the Woolly Mammoth. What we do know about them is that there brains were larger than ours, and though this does not necessarily mean they were more intelligent, it does indicate the ability for ‘higher thought’. There ‘range’ of occupation is equally interesting, with them leaving signs of their presence across Europe, the Russian steppes and Asia. There is no trace of them in Africa and they vanished from the world around 40,000 years ago. The general hypothesis concerning their extinction is that they simply ‘lost out’ to the ‘new, improved’ humans - but we may now have to rethink that as well.

They thrived in Europe and Asia for close on 60,000 years, most of it at a time when Northern Europe was buried beneath an ice sheet. There is evidence to suggest they may even have helped our early ancestors adapt, perhaps teaching them how to make clothes, or survival skills in the cold. So, what really happened to them?

The latest thinking is that they may have simply been unable to adapt as the ice retreated and the first hunter gatherers of Homo Sapiens were followed by increasing numbers of newcomers competing for food. Now comes the interesting bit about their DNA. Modern humans carry around 3% of Neanderthal genes in our X Chromosome, but no trace of it in the Y. Even more interesting, these genetic markers are completely absent from almost all African populations. These genes are also absent in the Australian Aboriginal gene pool, suggesting that they had no contact in their migration, with the Neanderthal peoples. It seems that our distant ancestors interbred with Neanderthal women, again suggesting that Neanderthal and Homo Sapien tribal groups were in contact long enough for the genes to become part of our genome. Equally interesting is the fact it is these genes which give European and Asian peoples the lighter skin tones, hair types and colouring and the variety of eye colours we have. 

Blue, green, grey and other eye colours are not found among African populations which have not interbred with non-African populations, and neither is the fine straight hair found elsewhere. It seems the Neanderthals have left us an interesting genetic legacy. The debate seems set to become more and more interesting as our understanding of the genetics involved in the development of humans as we know them today increases. 

I foresee some lively debates and some very interesting discoveries in this field for the future. I suppose one can but speculate what the world would look like if Homo Neanderthal had survived to become the dominant species ...

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