...I happen to follow the blog of one of the most ardent promoters of the sexual selection hypothesis (so ardent as to be quite controversial) and even he does not make the extreme claim that vitamin D has been completely debunked.
But he (Peter Frost) has released another blog post that makes the case even more strongly against the vitamin D hypothesis, as some of the counter evidence was finally released and found wanting (and suspiciously aided someone in advancing their career in probably politically correct circles), and Frost understands this stuff better than I do, so it's looking more and more like Tyler was right and that we can't add vitamin D to the sexual selection hypothesis, as interesting as it might have been, so kudos to Tyler on this. While Frost seems to accept that most of the whitening was relatively recent--possibly as recent as 11,000 years ago--the vitamin D hypothesis requires an even more recent lightening:
When Europeans turned white
http://evoandproud.blogspot.com/2012/10/when-europeans-turned-white.html
Beleza et al. (2012) generally confirmed Norton’s preliminary finding but found evidence that Europeans had lightened through a 2-stage process. Around 30,000 years ago, not long after entering Europe, the ancestors of today’s Europeans and East Asians lightened in skin color through a new allele at the KITLG gene. But the real whitening came much later, between 19,000 and 11,000 years ago among ancestral Europeans only, through new alleles at TYRP1, SLC24A5, and SLC45A2. This finding strikes down the two leading explanations for the whiteness of European skin:
1. As modern humans spread north from Africa and into higher latitudes with less solar UV, their skin had to lose pigmentation to maintain the same level of vitamin-D synthesis. Europeans therefore began to turn white once their ancestors entered European latitudes some 40,000 years ago (Loomis, 1970; Murray, 1934).
This explanation might account for the initial loss of pigmentation circa 30,000 BP, when ancestral Europeans probably became as light-skinned as Amerindians. But it cannot explain the much greater loss of pigmentation more than twenty thousand years later.
2. Some writers, like Sweet (2002), have suggested that the transition from hunting and gathering to farming increased the body’s need for vitamin D (because cereals contain phytic acids that immobilize calcium and phosphorus within the body and because a high-meat diet seems to reduce vitamin-D requirements). In Europe, however, this transition began only 8,000 years ago and did not reach northern Europe until 7,000-3,000 BP. ...
White skin was not climatically advantageous. It was visually advantageous, as were two other unique color traits....
White European skin evolved relatively fast during the last ice age, specifically from 19,000 to 11,000 years ago. This was also probably the same time frame for the evolution of European hair and eye colors. Anyway, that’s my bet.
These color traits—white skin and a diverse palette of hair and eye colors— are not adaptations to a cooler, less sunny climate. They are adaptations by early European women to intense mate competition, specifically a shortage of potential mates due to a low polygyny rate and a high death rate among young men.
On the other hand, while the sexual selection hypothesis is the primary hypothesis, it has not yet been able to conclusively explain everything (see
http://johnhawks.net/weblog/reviews/genetics/pigmentation/kenny-melanesia-blond-2012.html, for example), so there seems to possibly be something else at work too. Unfortunately, I forget what the other hypotheses were at this point that Frost hasn't already essentially debunked. LOL Mysteries are fun, though, so maybe I'll look into it again some day, or just wait for Peter Frost or John Hawks or Tyler to provide the answer.
One thing I don't recall seeing an explanation for, but maybe I'm just forgetting, is how could lack of polygyny account for most of the whitening when the Celtic peoples were supposedly very polygynous, like most or all pastoral societies, yet are some of the whitest? Frost mentions that red female hair is more highly valued in Celtic culture than other societies, though still less than blonde (
http://evoandproud.blogspot.com/2012_03_01_archive.html), but that doesn't seem enough to counter the polygyny on the face of it. Perhaps the so-called "Celtic" peoples were mostly pre-pastoral hunter-gatherer monogamous societies, perhaps pre-Celtic, counter to the current trend of scientific opinion? There is a minority of scientists who think this.
It's pretty refreshing that someone like Frost can make some politically incorrect hypotheses and provide rather strong evidence and even partially (though not fully) defend Rushton and not yet get pillaried, though maybe he just hasn't hit the libtards' radar screen yet.
Topic: Lighter Skin In Europeans due to agriculture? (Read 21173 times)