Monday, March 30, 2015
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Ancient DNA retrieved from archaeological skeletons of Europeans reveal a marked alteration in them over the past 5,000 years. Scientist s are still researching as to what factors have been influencing the human genome ever since the last Ice Age. Anthropologists and archaeologists have been working together on the skeletons and the DNA and have come to conclusions that the human genome has undergone significant changes in the past 5,000 years, thus leading to a change in their appearance. The DNA from archaeological skeletons shows that Europeans had darker skin pigmentation and had darker eyes and hair too.
The population geneticists have been able to detect echoes of natural selection in the genomes of living human beings. However, those techniques were found to be not very precise as to when the natural selection took place. Following a new approach, the researchers decided to analyze DNA from archaeological skeletons. By making use of computer simulations, they compared the prehistoric data with the contemporary Europeans. Based on the results, the researchers were able to conclude that positive selection did play a role here and there were striking differences particularly in those genes responsible for pigmentation of hair, eyes and skin.
Prehistoric Europeans were certainly darker than their descendants today. Over the last couple of hundreds of thousands of years, we find a preference for the darker phenotype and all our ancestors were darkly pigmented. However, as the humans began migrating to northern latitudes, in the last 50,000 years or so, things must have changed. It seems that over the past few thousand years, the natural selection has been supporting lighter pigmentation. According to the scientists the possible reason could be adaptation to the lower intensity of sunlight in northern latitudes. Having lighter skin under the conditions would be the best option. Population dynamics too are responsible for the changes in the human genome.
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