This was probably what began to happen in Britain 4,500 years ago, and during the Bronze Age that followed. Looking at the genes of different populations since that time, we see changes in seven regions of the genome that cannot be traced back to chance alone: nearly all of these genes can reasonably be linked to increased production of vitamin D and calcium. This would be consistent with the “selective pressures” that geography placed on these populations, we read in a Previously Posted Search March 16.
The authors – a geneticist and a statistician – agree that their analysis does not prove a causal relationship. But their research attracts attention because it goes in the direction of what has long been a matter of intuition: since emigration to the countries of Northern Europe, sane man It was facing less sunny states and shorter days, Their dark skin It had to be gradually replaced by pale skin, thus absorbing more UV rays, and thus producing more vitamin D. The introduction of agriculture put more pressure on it.
However, this intuition appears to have been confirmed by genetic analysis: the work of these two researchers consisted of a statistical analysis of observable variants in the genomes of 529 “British” from different periods and 98 of the day.
The difficulty with such analyzes is to establish that a variable imposed itself in a population because it brought about a ‘selective’ advantage – natural selection – rather than just chance. However, the essence of their conclusion is vitamin D: our bodies not only produce more of it under the influence of ultraviolet rays, but, in addition, vitamin D helps us absorb calcium, which, in turn, strengthens bones. Two factors brought a “selective” advantage to humans with this variant, which increases the chances of passing it on to their descendants.
Certainly, humans have lived in these areas for more than 4,500 years. Research published in 2018 And so he proved it The Cheddar Man, who lived in England 10,000 years ago, was dark-skinned.
But these ancestors, explain it new worldThey were hunters-gatherers, who could get vitamin D from fish. The introduction of animal husbandry and agriculture made the population less mobile – but it added milk to their diet, a source of calcium. This is what biologists call the “pressure” of evolution.
Photo: Representation of A Day in the Bronze Age / Hans Splinter / Flickr
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