Why Is There White Skin?

As a child I spent my summers in Fallon Nevada with my grandmother. Practically every day all day was dedicated to swimming in a pool, canal, river or reservoir under the blazing desert sun. By the end of the summer my tan would rival that of my Paiute friends. “Healthy” , they would say. Acquiring that tan, a badge of honor, was often painful but was the price to be paid, in the 40s and 50s, by a fair haired boy to  be able to play outside almost naked.

In Jr High, I learned about evolution so I inevitably asked; “What is the reproductive advantage of white skin?”. Not knowing that my ancestors came from where there is little sunshine, no satisfactory answer was out there. Over the decades bits of the story cobbled together. Black skin protects against sun damage among which is the destruction of folic acid in the blood stream.  OK there is a reproductive advantage of black skin. White skin, in allowing the sun to penetrate, more readily produces vitamin D which helps keep bones flexible thus aiding in surviving child birth.. OK a reproductive advantage for white skin.  So skin color is probably sun, folic acid and vitamin D in a circle dance. Not complete, I’m sure, but sufficient. Then a dermatologist told me that white skin is a mutation and left it at that.  Such a mutation would obviously be passed on in Northern Europe but not in Southern India because of the differing reproductive effects.

So now there is a story coming together still leaving some quibbles as to the expansion of Homo Sapiens into Europe being so rapid and so late. Homo Saps made it to Australia across vast stretches of continent and ocean before they made it to Europe. That said to me that the mutation didn’t arrive until maybe 40,000 years ago when Homo Saps started encroaching on Europe and Siberia. Neanderthals had been in Europe for at least 200,000 years before that. It follows that they must have had white skin. This is all paleo anthropology which is at most 5% science and the other 95% story telling.

Several years ago DNA analysis of a Neanderthal specimen showed evidence that he may have been a redhead. Aha! Now there’s more to the story reminiscent of Jane Auel’s “Clan of the Cave Bear” series. Homo Saps and Neanderthals interbred! The accepted science at the time denied that possibility, but in the last few years DNA evidence is showing that all humans outside Africa have some DNA.  from Neanderthal and/or Denisovan, a Neanderthal cousin.  Another example of the fact that the meal scientist most enjoy feeding each other is crow.  Europeans have the most Neanderthal DNA of any region, which gives me some pleasure when I see a white bigot exhibiting his prejudices by deprecating some one else’s family tree.

How did all this happen? is the next obvious question. However it happened and it must have happened many times, the pregnant woman had to give birth and raise her child amongst Homo Saps so that he/she could pass on lighter skin. Over time, as Homo Saps moved into the lands of little sunshine, the offspring with the lightest skin would have a reproductive advantage. Even if that advantage was only 1 or 2% over 10,000 years the entire population would have white skin like the Neanderthals with an occasional throw back or black sheep.

The story (hypothesis) that makes most sense is that the mutation for white skin occurred in Neanderthals and then was passed on to Homo sapiens

I entertain myself with imaginary movie  scenarios. One involves an ebony beauty intent on gathering clams along the North shore of the Black Sea  She surprises a redheaded hunk bent at the same task. After exchanging smiles, she indicates that he has something that she needs. He willingly obliges not knowing or caring that in 10,000 years his species will be gone, at least partially, because it no longer will have a reproductive advantage in Europe. However some of his DNA will  survive to wreak havoc upon the planet. Once again it seems that a common language is not necessary to exchange some very important favors. When said face to face, this line elicits laughs and sometimes a wistful smile accompanied by a far away look. If I could capture the emotions and images behind those smiles, I would truly have a movie.

That is the story as I imagine it. If I have to eat crow,  and you have evidence, be sure and inform me and I’ll send you a photo of me enjoying the repast.

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