Monday, July 20, 2015

7,000-Year-Old Human Bones Suggest New Date for Light-Skin Gene


http://www.livescience.com/42838-european-hunter-gatherer-genome-sequenced.html

illustration of ancient hunter gatherer

An ancient European hunter-gatherer man had dark skin and blue eyes, a new genetic analysis has revealed.
The analysis of the man, who lived in modern-day Spain only about 7,000 years ago, shows light-skin genes in Europeans evolved much more recently than previously thought.
The findings, which were detailed today (Jan. 26) in the journal Nature, also hint that light skin evolved not to adjust to the lower-light conditions in Europe compared with Africa, but instead to the new diet that emerged after the agricultural revolution, said study co-author Carles Lalueza-Fox, a paleogenomics researcher at Pompeu Fabra University in Spain.
Sunlight changes
Many scientists have believed that lighter skin gradually arose in Europeans starting around 40,000 years ago, soon after people left tropical Africa for Europe's higher latitudes. The hunter-gatherer's dark skin pushes this date forward to only 7,000 years ago, suggesting that at least some humans lived considerably longer than thought in Europe before losing the dark pigmentation that evolved under Africa's sun.
Blue eyes, dark skin
The new analysis of that DNA now shows the man had the gene mutation for blue eyes, but not the European mutations for lighter skin.
The DNA also shows that the man was more closely related to modern-day northern Europeans than to southern Europeans. 
The discovery may explain why baby blues are more common in Scandinavia. It's been thought that poor conditions in northern Europe delayed the agricultural revolution there, so Scandinavians may have more genetic traces of their hunter-gatherer past — including a random blue-eye mutation that emerged in the small population of ancient hunter-gatherers, Lalueza-Fox said.
Skin changes
The finding implies that for most of their evolutionary history, Europeans were not what many people today would call 'Caucasian', said Guido Barbujani, president of the Associazione Genetica Italiana in Ferrara, Italy, who was not involved in the study.
Instead, "what seems likely, then, is that the dietary changes accompanying the so-called Neolithic revolution, or the transition from food collection to food production, might have caused, or contributed to cause, this change," Barbujani said.
In the food-production theory, the cereal-rich diet of Neolithic farmers lacked vitamin D, so Europeans rapidly lost their dark-skin pigmentation only once they switched to agriculture, because it was only at that point that they had to synthesize vitamin D from the sun more readily.
wow we are not who we think we are after all some of us anyway.  hope there aren't too many grave spinners and hair on fire when they find out that Africa well let's say we can say to them "go back to Africa where you came from KKK",  BUT THE REPUBLICAN POLITICIANS WILL TELL THOSE ABOUT TO JUMP OFF A CLIFF "IT'S JUST LIBERAL SCIENTIST LYING" and all will be well in Mudville, 

they don't believe in science but isn't that only when it comes to climate change????  well now they have something else to rant against science and scientist about even though they are not scientist themselves.  much to some's chagrin we are all brothers with different mothers,  somehow i find humor in that.