Pale Skin Blue Eyes Light Brown Hair Origin

Part 2

Many people have proposed that interbreeding between Homo-sapiens & Neanderthals was the main reason why Europeans today have light skin , eyes & hair , However one thing that people seem to forget was that Neanderthals were typically dark-skinned with brown eyes.

The SNP-mutations from Neanderthals showed their genetic pigmentation profile to be the same as Melanesians and Yoruba people:

In 2007 however there was a report published which stated that researchers obtained 2 samples of Neanderthals in Croatia that had the genes for red hair (known as the MC1R gene) but it soon turned out that these Neanderthal samples did not carry the same MC1R mutation responsible for red hair in modern Europeans (the mutation in question is known as Arg307Gly).

Surprisingly the highest introgression for this Neanderthal derived MC1R variant was found in Taiwanese aboriginal people and Cheyenne Native Americans. Europeans have the lowest introgression for this gene, Mongolians have the highest.

The 2007 report further stated that only 1% of the entire Neanderthal population would've had red hair , the other 99% had dark hair & skin as usual.

About 5 years later in 2012 another report was published which claimed that 3 samples of Neanderthals had the genes for light skin (known as the SLC24A5 gene which alters the A111T protein) , the researchers in the report also claimed that this gene was strong enough to have caused pale skin , the study soon followed with a lot of criticism , one author for Discover-Magazine wrote:

"This is artlessly rendered. If light skin in Europeans was due to a single gene of large effect then ~20 of African Americans would have nearly white skin (assuming dominant effect, it would be 4% if it was recessive).

There are two candidate genes which come to mind as possibilities for what might make Europeans white in the mind of this researcher. The first is SLC24A5 , a locus which is nearly disjoint in frequency between Europeans and Africans. This locus alone can explain 25-40% of the between population difference in pigmentation.

But this locus does not make you white; otherwise I would be white! I'm a homozygote for the "European" variant of the SNP at this locus which differs across populations, as are both my parents.

The total frequency of the "European" variant in South Asians is probably comfortably above 50%. A better candidate would be a SNP on SLC45A2 which is present in high proportions in European populations (~90 percent within Europe, ~10 percent in South Asia). But observe that this allele on SLC45A2 is not sufficient for light skin."

According to the author In order for humans (and homonins) to lighten they need to at least carry all the dipigmentation genes. The samples mentioned in the report above however did not.

Despite all the criticism the discovery of this SLC24A5 gene in Neanderthals has proven 2 things:

1) That light skin may have been present in certain species of humans 30 000 years ago long before homo-sapiens had these genes.

2) And that light skin was also super rare (as would be expected from recessive genes)

So how & why did so few Neanderthals had the genes for light skin/hair?

From one study we know that at least 8% of Neanderthal DNA comes from unknown species, hints of unknown groups from Asia and Africa has left genes in both Denisovans and modern humans.

Reports also show that Neanderthals shared 17% of their genome with Denisovans. The only genes left of Denisovans today is found among Melanesians , Which might explain why Melanesians also shared so many SNP-mutations with Neanderthals (shown above).

It's also unclear whether there is a correlation with the admixture of Denisovans and red/blonde hair found among Melanesians and Neanderthals , although it seems very likely to be the case.

But so far It seems that just like the Melanesians , people of European /Caucasians decent most likely received their recessive genes from another (unknown) species of humans that has yet to be discovered.

edit on 11-4-2017 by ancienthistorian because: (no reason given)

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Source: https://www.abovetopsecret.com/forum/thread1167966/pg1

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