Natural selection determines our specific traits. Yes, we believe so from the scientific point. Pigmentation is a particularly conspicuous human phenotypic variation.
Eye, hair, and skin pigmentation are highly variable in humans, particularly in western Eurasian populations. What are the underlying determinants for these different types’ colors in our body? A new study led by Dr. Mark G. Thomas from the University College London, UK reported their findings on this phenomenon in the journal of Proceedings of the National Academy of Sciences of the United States of America, and revealed that three key genes known to be involved in human pigmentation pathways - HERC2, SLC45A2, and TYR - using allele frequency estimates from Eneolithic, Bronze Age, and modern Eastern European samples and forward simulations.
Neutrality was overwhelmingly rejected for all alleles studied, with point estimates of selection ranging from around 2–10 percent per generation. Our results provide direct evidence that strong selection favoring lighter skin, hair, and eye pigmentation has been operating in European populations over the last 5,000 y.
As the authors summarized that a combination of selective pressures associated with living in northern latitudes, the adoption of an agriculturalist diet, and assortative mating may sufficiently explain the observed change from a darker phenotype during the Eneolithic/Early Bronze age to a generally lighter one in modern Eastern Europeans, although other selective factors cannot be discounted.
The selection coefficients inferred directly from serially sampled data at these pigmentation loci range from 2 to 10% and are among the strongest signals of recent selection in humans.■
(Source: bonoi.org)
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