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Alan
09-01-14, 23:13
http://2.bp.blogspot.com/-ad3mZyyUew0/Us6_OzZjb2I/AAAAAAAAJdw/PU1DxDNAei8/s1600/F1.large.jpg
From the paper:
Adjustment for undercounting is substantial, increasing the estimated age for the combined samples to 12.4 (95% confidence interval 7.6−19.2) kya. If mutation rates in recent humans are lower than predicted from the human-chimpanzee divergence (Scally and Durbin 2012), true ages will be even older. Our adjusted dates overlap those previously reported (Beleza et al. 2012) and are also consistent with the lower limit for the origin of A111T set by the finding that the Alpine “iceman” dated to 5.3 kya was homozygous for this variant (Keller et al. 2012).
Taking the 12.4ky estimate and multiplying by two (for the slower autosomal mutation rate) yields an estimate of 25ky, so it seems that this allele did not accompany the earliest modern human colonists of West Eurasia but emerged in some region and spread from there. It will be interesting to see (through ancient DNA) by what processes of migration, admixture, and selection this transpired.



G3 doi: 10.1534/g3.113.007484

Molecular Phylogeography of a Human Autosomal Skin Color Locus Under Natural Selection

Victor A. Canfield et al.

Divergent natural selection caused by differences in solar exposure has resulted in distinctive variations in skin color between human populations. The derived light skin color allele of the SLC24A5 gene, A111T, predominates in populations of Western Eurasian ancestry. To gain insight into when and where this mutation arose, we defined common haplotypes in the genomic region around SLC24A5 across diverse human populations and deduced phylogenetic relationships between them. Virtually all chromosomes carrying the A111T allele share a single 78-kb haplotype that we call C11, indicating that all instances of this mutation in human populations share a common origin. The C11 haplotype was most likely created by a crossover between two haplotypes, followed by the A111T mutation. The two parental precursor haplotypes are found from East Asia to the Americas but are nearly absent in Africa. The distributions of C11 and its parental haplotypes make it most likely that these two last steps occurred between the Middle East and the Indian subcontinent, with the A111T mutation occurring after the split between the ancestors of Europeans and East Asians.



http://dienekes.blogspot.de/2014/01/slc24a5-light-skin-pigmentation-allele.html

"The distributions of C11 and its parental haplotypes make it most likely that these two last steps occurred between the Middle East and the Indian subcontinent,"

Looks to me more like between West Asia (minus Arabia) and western part of South_Central Asia (minus India).

In one sentence: It reminds me to the distribution of Caucasus_Gedrosia.

Maleth
01-08-14, 22:44
first men absolutely "black": I don't know...

absolutley black I dont know but very dark yes, I presume so. According to today's understanding and our knowledge to where we all originate from is in an area with one of the highest UV indexes you can find on the globe. Its not just about UV disposition but also general cloud cover (which is minimal) and also terrain reflection of UV. (I think of one being able to get a suntan when skiing for example)


Researchers suggest that human populations over the past 50,000 years have changed from dark-skinned to light-skinned and vice versa as they migrated to different UV zones,[4] (http://en.wikipedia.org/wiki/Human_skin_color#cite_note-Jablonski2011AN-4) and that such major changes in pigmentation may have happened in as little as 100 generations (~2,500 years) through selective sweeps (http://en.wikipedia.org/wiki/Selective_sweep). http://en.wikipedia.org/wiki/Human_skin_color

As we all know there are different skin tones in subsaharan African from Black to very dark brown, but essentially must have been very dark in relation to the wonderful mechanics of nature to help humans survive in what could have been very tough climatic conditions, and the relatively amazing short time to adapt to the other opposite extremities to be able to conquer most areas around the globe. The adaptation of Plants is equally fascinating conquering places that are hot but humid, hot and dry, cold and dry and cold and wet.

LeBrok
02-08-14, 01:09
absolutley black I dont know but very dark yes, I presume so. According to today's understanding and our knowledge to where we all originate from is in an area with one of the highest UV indexes you can find on the globe. Its not just about UV disposition but also general cloud cover (which is minimal) and also terrain reflection of UV. (I think of one being able to get a suntan when skiing for example)

http://en.wikipedia.org/wiki/Human_skin_color

If not invention of clothing, white and swarthy people couldn't be able to live in Saharan Africa or Arabian Peninsula, where is hot and dry. Bedouins are usually wrapped up in cloths from head to toes.

Maleth
04-08-14, 21:07
If not invention of clothing, white and swarthy people couldn't be able to live in Saharan Africa or Arabian Peninsula, where is hot and dry. Bedouins are usually wrapped up in cloths from head to toes.

what an interesting subject! I wonder how long lets say people have been covering their body? In fact it seems odd (since you mentioned it) that Berbers have covered most of their body compared to subsaharan Africa who (before recent) seemed to cover much less.

I know I did read somewhere that its thought that the initiation of wearing clothes have something to do with loosing body hair. (however if this was so why aren't African tribes and others that sparsely wear any clothing very hairy?) However I personally believe that wearing of clothes in hot climates have something to do with the whitening of the skin. (meaning less UV rays directly on much of the skin....besides all the other factors that were already debated). This can take a whole debate in its own right.

LeBrok
05-08-14, 03:31
what an interesting subject! I wonder how long lets say people have been covering their body? In fact it seems odd (since you mentioned it) that Berbers have covered most of their body compared to subsaharan Africa who (before recent) seemed to cover much less.

I know I did read somewhere that its thought that the initiation of wearing clothes have something to do with loosing body hair. (however if this was so why aren't African tribes and others that sparsely wear any clothing very hairy?) However I personally believe that wearing of clothes in hot climates have something to do with the whitening of the skin. (meaning less UV rays directly on much of the skin....besides all the other factors that were already debated). This can take a whole debate in its own right.
I don't think there was ever much incentive to wear cloths for black people in Africa except for some decorative and ceremonial purposes. The first need came in Near East during winter time, not mentioning need for clothing in Europe and Central Asia. To keep warm people used animal skins exclusively till invention of textiles in Neolithic. Neandertals wear animal skins too, and probably as long as they lived in northern latitudes, for about half a million years.

Wearing cloths to keep warm/alive, is an eloquent proof that Out of Africa (Sub Saharan Africa in particular) theory is the correct one. Only in natural habitat animals adapt to survive just with their own skin.
Without clothing we would need to wait couple of millions of years to grow long fur to be able to advance North (Taming fire came handy to keep warm at night too). I wonder how hairy Neanderthals were? Probably a lot. Some Europeans are very hairy with substantial "coat" of hair on their back and all over their body. Probably a gift from Neanderthals. :)


http://24.media.tumblr.com/tumblr_md6f3mYPxL1qlvpiuo1_500.jpg




As extra cover helped people to expand North, and likewise the extra cover allowed white people to settle Near East and North Africa.

Maleth
05-08-14, 10:18
I don't think there was ever much incentive to wear cloths for black people in Africa except for some decorative and ceremonial purposes.

The climate permits it. Not much fluctuation in temperature, just a wet and dry season. So full absorption of UV rays on bare skin as most of the living is done outdoors. Its also the closest part of the globe to the sun.


The first need came in Near East during winter time, not mentioning need for clothing in Europe and Central Asia.

Even North Africa could have been an initiation for body cover. There are defined seasons Hot/Warm May to October and cooler the rest of year (needing body cover). Temperatures in Dessert can go down to 0f/-18c in winter during the night!. Same with Near East. So covering the body would already help to trigger a reaction to the genetic command centre.

Obviously it gets more and more accentuated the higher the latitude were winters are longer and summers shorter. Wearing even heavier clothes for a longer period of time, the need to spend more time indoors compared to warmer areas and less UV rays around to higher latitudes. MUCH less exposure on the skin.

Will I be assuming too much if not only grains (vs meats), but body cover had alot to do with the whitening of the skin? I don't think anyone has ever mentioned that and its kind of common sense.


Without clothing we would need to wait couple of millions of years to grow long fur to be able to advance North (Taming fire came handy to keep warm at night too).

Ok maybe fur can keep a mammal warm, but there are a number of primates that did not totally shed their fur and been living in particular hot areas for thousands of years. That can explain a few things about the necessity of fur in the survival of species (like you said that unlike humans they don't wear clothes)



I wonder how hairy Neanderthals were? Probably a lot. Some Europeans are very hairy with substantial "coat" of hair on their back and all over their body. Probably a gift from Neanderthals. :)

If having body cover means the shedding off of body hair (as I read in some article) then its possible that they possessed smooth skin as body cover was a must. Just my opinion but I feel 'Generally speaking' is that people around the Med and Near east up to Pakistan seem to have much more body hair then say Nordics or Subsuharan populations. I wonder if that is a reminiscent of the past or a present climatic need.


http://24.media.tumblr.com/tumblr_md6f3mYPxL1qlvpiuo1_500.jpg

andrewqazx
13-01-15, 14:35
Light skin genes could originate from neanderthal mixing with cro magnons if there even was such a thing