Tuesday 28 January 2014

Europeans, DNA and 7,000 Years

 So, in a snub to all racists, the DNA of a hunter gatherer who lived in what is now Spain 7,000 years ago has been analysed and has revealed that Europeans gained our white skin a lot later that first believed.

The genetic material was recovered from a tooth of La Brana 1, an ancient man whose skeleton was found in a deep cave system in Spain in 2006, revealed the extremely odd combination of dark skin and blue eyes, according to the study in the journal Nature.  Europeans from the Mesolithic Period between 10,000 and 5,000 years ago, when La Brana lived, were thought to have already been fair-skinned due to low ultraviolet radiation levels at these high latitudes.

"Until now, it was assumed that light skin colour evolved quite early in Europe, (during) the Upper Palaeolithic... But this is clearly not the case," study co-author Carles Lalueza-Fox from Spain's Evolutionary Biology Institute said.  "This individual had the African variants for the pigmentation genes."

For those of us who are not history geeks, the Upper Palaeolithic or Late Stone Age stretched from 50,000-10,000 years ago, followed by the Mesolithic or Middle Stone Age that lasted until about 5,000 years ago, when it was followed in Europe by the Neolithic or New Stone Age.

It is widely accepted that Man's oldest common forefather was dark skinned, and that people became more pale as they moved further north out of Africa into colder climates with less sunlight and subsequent migrations and mixing created the wide range of hues we have today.

La Brana's genome is the first of a European hunter-gatherer to be fully sequenced and when compared to today's humans, it was found to be most closely genetically related to northern Europeans like the Swedes or Fins.  Lalueza-Fox and his team also found the genetic signature for blue eyes and dark hair and while the exact hue of skin cannot be determined, the scientists say its combination with blue eyes was not to be found in modern Europeans today.  I have to admit that if I saw someone with that combination of features walking down the street they would certainly draw my attention.

So light-skinned Europeans emerged "much later" than once believed - possibly only in the Neolithic era when erstwhile hunter-gatherers became farmers and the cause may have been a change in diet and lower vitamin D intake associated with this lifestyle change.   In the absence of natural vitamin D, the human skin can produce its own in contact with the Sun - but dark skins synthesise much less than fair ones - creating an evolutionary incentive for change.  So my guess would be that blue eyes were needed earlier to cope with the low light levels but we didn't need the white skin until later.

The probe also found that La Brana 1 had not yet acquired the genetic mutation that allowed later humans to digest milk and starch more easily - an adaptation that probably coincided with the birth of agriculture in the Neolithic age.

This change in skin tone and digestive trait, if it was caused by the arrival of agriculture in our society, would certainly be compatible with the program 'Mankind the History of Us All'.  According to this program, which I watched last year our original ancestor, the first Man that they have been able to genetically trace, lived in the African Rift Valley and was dark skinned.  So 'Adam' wasn't white like they depict him in all the illustrated Bibles, he was black.  He was also two inches taller than the average modern American.

Say what you like about the 'savages', a hunter-gatherer lifestyle obviously got homo sapiens off to a good start.

However, many thousands of years later, long after mankind had domesticated the wolf, the mother of farming, as she is known, realised that if she planted so of the grain she had gathered then she would know where is was growing and harvesting it would be that much easier.  This was the start of farming and according to 'Mankind the History of Us All', farming has been at the root of most of mankind's problems since.  It tied us down to the land so we couldn't move so we came into conflict over resources, which was the start of war.  All the major plagues, from TB to the Bubonic, where introduction to mankind by living in close contact with farm animals, so disease seriously arrived when we started farming.  Then when the crops failed there were too many of us to go back to the hunter-gatherer lifestyle so people starved, which is famine.  Does it appear that I'm listing the four riders of the Apocalypse?

It has also been found that about a thousand years after we started farming the human race shrunk.  The average farmer man was only five foot two inches and the average farmer woman was only four four eight.  Farming in other words, was not good for us.  So you have to ask why are we so hung up on it?  Oh that's right, with 7 billion people now living on earth there is no way we can feed that many out of the hunter-gatherer lifestyle.  I'd say we could be in big trouble if the crops fail big time.

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