The DNA blueprint we carry with us today has been much more influenced by natural selection than we thought, with genetic variants behind red hair and pale skin among those selected for survival.
Natural selection is sometimes called survival of the fittest, because organisms best adapted to survive are more likely to reproduce and pass on their genes.
Previously, the consensus was that since we moved from hunting to farming, our genetic evolution had largely stagnated. Scientists had previously found just 21 sites in the genome shaped by natural selection over the past roughly 10,000 years in Europeans.
However, thanks to a mega-study recently in Naturethat number rose into the hundreds: 479 genetic variants appear to have been strongly selected for or against. In addition to the variants that control hair color and skin pallor, other variants that are now associated with disease risk and psychiatric traits have been identified.
“This single paper doubles the size of the ancient human DNA literature,” praises the study’s corresponding author and geneticist, David Reichfrom Harvard University, cited by .
The discoveries were made possible by an unusually large collection of ancient genomes – coming from the remains of nearly 16,000 individuals over the past 10,000 years in Western Eurasia.
Gene variants MC1R which are strongly associated with the red hair and “pale” skin may have spread because fair skin absorbs vitamin D from sunlight more easily.
This may have become more advantageous as we moved from a hunter’s diet to a farmer’s diet, with more plants and grains.
A Sunlight has become a more important source of vitamin Dand the skin of the European adapted accordingly – at least, that is the hypothesis.
The researchers found that while some of the identified variants were functioning in groups, others rose and fell over time and not all were as robust to change as the red-haired and pale-skinned variants.
