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by xenophonf 1175 days ago
> the genetic signature for a certain natural skin pigmentation

Such a thing does not exist:

> Our understanding of the genetics of melanin formation and distribution within cutaneous and follicular tissues has recently greatly expanded through the power of genome-wide association studies (GWASs) using large databases such as those of the UK Biobank (22) and 23 and Me (51). This research has provided new insights into the biology of skin and hair color and underscores the highly polygenic nature of these two traits, with complex epistatic interactions apparent between the genes involved.

(https://www.annualreviews.org/doi/10.1146/annurev-genom-0831...)

Again, there's no biological basis for "race":

> People today look remarkably diverse on the outside. But how much of this diversity is genetically encoded? How deep are these differences between human groups? First, compared with many other mammalian species, humans are genetically far less diverse – a counterintuitive finding, given our large population and worldwide distribution...

> Early studies of human diversity showed that most genetic diversity was found between individuals rather than between populations or continents and that variation in human diversity is best described by geographic gradients, or clines. A wide-ranging study published in 2004 found that 87.6% percent of the total modern human genetic diversity is accounted for by the differences between individuals, and only 9.2% between continents. In general, 5%–15% of genetic variation occurs between large groups living on different continents, with the remaining majority of the variation occurring within such groups (Lewontin 1972; Jorde et al. 2000a; Hinds et al. 2005). These results show that when individuals are sampled from around the globe, the pattern seen is not a matter of discrete clusters – but rather gradients in genetic variation (gradual geographic variations in allele frequencies) that extend over the entire world. Therefore, there is no reason to assume that major genetic discontinuities exist between peoples on different continents or "races." The authors of the 2004 study say that they ‘see no reason to assume that "races" represent any units of relevance for understanding human genetic history. An exception may be genes where different selection regimes have acted in different geographical regions. However, even in those cases, the genetic discontinuities seen are generally not "racial" or continental in nature but depend on historical and cultural factors that are more local in nature’ (Serre and Pääbo 2004: 1683-1684).

(https://humanorigins.si.edu/evidence/genetics/human-skin-col...)

1 comments

It must. If you take a baby born to two sub-Saharan African parents and a baby born to two Northern European parents, and keep them in boxes with identical stimuli from birth, they will have drastically different skin tones. If that's not genetic, then what is it?

I'm not saying it wouldn't be an unbelievably complex signature, but it would be a signature nonetheless.