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Freckles come from a mutation in genes.
"The presence of freckles is related to rare alleles of the MC1R gene, though it does not differentiate whether an individual will have freckles if they have one or even two copies of this gene. Also, individuals with no copies of the MC1R do sometimes display freckles. Even so, individuals with a high number of freckling sites have one or more of variants of the MC1R gene. Of the variants of the MC1R gene Arg151Cys, Arg160Trp, and Asp294. His are the most common in the freckled subjects. The MC1R gene is also associated with red hair more strongly than with freckles. Most red haired individuals have two variants of the MC1R gene and almost all have one. The variants that cause red hair are the same that cause freckling.Freckling can also be found in areas, such as Japan, where red hair is not seen. These individuals have the variant Val92Met which is also found in Caucasians although it has minimal effects on their pigmentation. The R162Q allele has a disputed involvement in freckling.
The variants of the MC1R gene that are linked with freckles started to emerge in the human genotype when humans started to leave Africa. The variant Val92Met arose somewhere between 250,000 - 100,000 years ago, long enough for this gene to be carried by humans into central Asia. Arg160Trp is estimated to have arisen around 80,000 years ago while Arg151Cys and Asp294His have been estimated to arise around 30,000 years ago. The wide variation of the MC1R gene exists in people of European descent because of the lack of strong environmental pressures on the gene. The original allele of MC1R coded for dark skin with a high melanin content in the cells. The high melanin content is protective in areas of high UV light exposure. The need was less as humans moved into higher latitudes where incoming sunlight has lower UV light content. The adaptation of lighter skin is needed so that individuals in higher latitudes can still absorb enough UV for the production of vitamin D. Freckled individuals tend to tan less and have very light skin which would have helped the individuals that expressed these genes absorb vitamin D"
> http://hmg.oxfordjournals.org/content/10/16/1701
A study showing you find high level percent of mutation in this gene in the population Dutch, Swedish, Irish, Brittish... :
> https://mathildasanthropologyblog.wo...mcr1-variants/
BTW, some Neanderthals were redhead and had freckles but it seems you found dark haired and blond Neanderthals as well.
> http://news.bbc.co.uk/2/hi/science/nature/7062415.stm
"The Out-of-Africa model proposes that modern humans originated in Africa and migrated north to populate Europe and Asia. These migrants most likely had a functional MC1R variant and, accordingly, dark hair and skin as displayed by indigenous Africans today. As humans migrated north, the absence of high levels of solar radiation in northern Europe and Asia relaxed the selective pressure on active MC1R, allowing the gene to mutate into dysfunctional variants without reproductive penalty, then propagate by genetic drift." Studies show the MC1R Arg163Gln allele has a high frequency in East Asia and may be part of the evolution of light skin in East Asian populations. No evidence is known for positive selection of MC1R alleles in Europe and there is no evidence of an association between MC1R and the evolution of light skin in European populations."
If homo sapiens migrated from africa and had a mutation of MC1R by low exposure to the sun, how do you explain Neanderthal had this mutation in genes also ? for me that's not coming from Africa in particular.
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Originally Posted by Dick
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