Did we inherit red hair, blue eyes and pale skin from Neanderthals?

All Eurasian people apparently inherited various Neanderthalian genes relating to the immune system (e.g. HLA types), including genes that increased the risk for some autoimmune diseases such as type-2 diabetes and Crohn’s disease. Physical features inherited from Neanderthal by Europeans and Middle Easterners include prominent eyebrows, big eyes, strong jaws and wide shoulders. 70% of East Asians also inherited mutations in the POU2F3 gene, which is involved in keratin production and may be responsible for straightening hair.

According to the Canadian anthropologist Peter Frost, the current level of hair colour diversity in Europe would have taken 850,000 years to develop, while Homo sapiens has been in Europe no longer than 45,000 years. This is evidence enough that genes for fair hair were inherited from interbreeding with Neanderthals.

DNA tests demonstrated that Neanderthals possessed fair skin, and at least some subspecies had reddish hair too.

Homo sapiens apparently did not inherit the whole light skin, light eyes and light hair package at once, but through continuous interbreeding with various Neanderthal subspecies in Europe, the Middle East and Central over tens of thousands of years. It has been confirmed that Mesolithic (Western) Europeans had blue eyes, but dark skin and dark hair.

There are several genes influencing skin colour. Among them, the BNC2 gene, which influences saturation of skin colour and is responsible for freckling, was confirmed by Sankararaman et al. (2014) to have come from Neanderthal. It is found at varying frequencies in all Eurasian populations and is most common among Europeans (70% have at least one copy of the Neanderthalian version, against 40% for East and South Asians). Mutations in the SLC24A5 gene, responsible for 40% of skin colour variations between Europeans and sub-Saharan Africans, appear to have been spread to Europe by Neolithic farmers from the Near East and especially by the Proto-Indo-Europeans from the Pontic Steppe during the Bronze Age (more info). Mutations for blond and red hair have yet been not found in ancient European DNA samples prior to the Bronze Age, except in Northeast Europe. So it seems that fair skin and blond or red hair were originally passed on to Homo sapiens in the Middle East or Central Asia, rather than in Europe.

As for the genes for light eyes, there is a relatively high likelihood that they were inherited from Neanderthals too, rather than having emerged independently in Europeans fairly recently. It hasn’t been proven yet that Neanderthals had blue, green or hazel eyes because only one Neanderthal sample has been fully sequenced at present. But the statistical probability that such mutations would arise and be positively selected in Neanderthals, who evolved for 300,000 years in the high latitudes of Europe, is far higher than in European Homo sapiens, who have lived for only 45,000 years in Europe, and less than 30,000 years in northern Europe. Not all Neanderthal groups would have been blue eyed, though. Neanderthals were much more genetically diverse than modern humans, who all share a recent ancestry three times earlier in time than Neanderthals subspecies between themselves. If blue eyes indeed originated in Neanderthal, different Neanderthal populations could have passed blue eyes genes several times to Homo sapiens in Europe, the Middle East or Central Asia. It’s not even granted that the two main genes, OCA2 and HERC2, were passed at the same time or to the same people. They might only have converged later in Europeans. Another alternative is that only one of these genes came from Neanderthal while the other arose in Homo sapiens.

Mesolithic Europeans from Spain and Luxembourg have been confirmed to have possessed the HERC2 mutation for blue eyes (see Olade et al. (2014) and Lazaridis et al. (2014)). This mutation is also found in parts of Asia settled by the Proto-Indo-European speakers belonging to the paternal lineages R1a and R1b, including the Altai, southern Siberia, Central Asia, Iran and the Indian subcontinent. Since the the Proto-Indo-Europeans carried very different paternal lineages from Mesolithic Europeans (Y-haplogroups C, F, K and I), and only shared a few very old maternal lineages, like haplogroups U4 and U5, their HERC2 mutation could have been inherited from a common Paleolithic ancestor or passed on by two different groups of Neanderthals to separate tribes of Homo sapiens during the Upper Paleolithic period.

Source: Eupedia