.jpg/800px-Ethiopian_Manuscript_Paintings_(2400615763).jpg?uselang=fr)
Ethiopian manuscript paintings (source: A. Davey).
Ethiopians have a self-image that is lighter-skinned than their actual selves.
If the prevalence of SLC24A5 is higher in Ethiopia than the degree of admixture
from lighter-skinned peoples across the Red Sea, this discrepancy may be explained
by social selection for lighter skin.
.jpg?uselang=fr){kind=link}
Greg Cochran has been asking why the “European”
allele for SLC24A5 has been so successful, not only in Europe but also
elsewhere. He seems to be hinting that this allele has a selective advantage
that is unrelated to skin color.
I posted the following comments at his website. References
have been inserted for this post.
***************************************************
SLC24A5 is one of three genes involved in the
whitening of European skin, the other two being SLC45A2 and TYRP1. This
whitening occurred over a relatively short time and long after the entry of
modern humans into Europe some 40,000 years ago. Sandra Beleza’s team estimates
that all three genes “went white” between 11,000 and 19,000 years ago (Beleza et al, 2013). Victor Canfield’s team, working only with SLC24A5, estimates
between 7,600 and 19,200 years ago (Canfield et al., 2014).
So, yes, white European skin is not an adaptation to
weaker sunlight; otherwise, it would have evolved much earlier. Are we looking at
some pleiotropic effect then? In that case, this effect would involve not only
SLC24A5 but the other two genes as well. Perhaps, but I’d like to see the
evidence.
No, I’m not going to invoke sexual selection to
explain the apparent success of the “European” allele for SLC24A5. Sexual
selection, especially sexual selection of women, occurs under very limited
circumstances. I believe that there was
an episode of very intense sexual selection of women, but this episode was
confined to northern and eastern Europe during the time frame of 10,000 to
20,000 years ago, i.e., the last ice age (Frost, 2006; Frost, 2008).
How then do we explain the much greater geographic
and historical success of this allele? The answer is part of the larger one of
why lighter-skinned folks have done better than darker-skinned folks. Mean
temperature is inversely correlated with technological complexity, even going
back to the hunter-gatherer stage of cultural evolution. This is partly because
colder environments created a greater need for heat conservation (by means of tailored clothing and insulated shelters) and
partly because their food resources were more dispersed and typically available for short
periods of time. There was thus strong selection in such environments for time budgeting, forward
planning, and the ability to manage storage technologies (ice cellars) and
untended facilities (traps, snares). Northern hunters were pre-adapted for
technological complexity and thus better able to exploit the sort of complex
cultural environments that developed much later in time (Hoffecker, 2002, pp.
6-12).
Is this the whole story? You point to Ethiopians as
an example where SLC24A5 seems to be present at a higher frequency than
Caucasian admixture. This discrepancy can probably be explained by social
selection for lighter skin, as indicated by an Israeli study that found
light-skin preference among Falasha children (Munitz et al., 1987). This preference may be learned, although
there is evidence that people are predisposed to associate lighter skin with
certain good qualities (as a result of a mental algorithm that uses skin tone
for identification of women and young infants) (Frost, 2011). For whatever
reason, social selection for lighter skin is a reality in Ethiopia, and it
probably has had some impact on the prevalence of SLC24A5.
Question from ‘RS’: Sexual selection, especially sexual selection of women, occurs under
very limited circumstances. So you are equally attracted to all women?
Sexual selection is not the same thing as sexual
preference. In other words, what you prefer is not necessarily what you will
get. It all comes down to the law of supply and demand.
Sexual selection occurs when too many of one sex
have to compete for too few of the other. Normally, the males have to compete
for the females. The reverse is rare in nature. It happens when (1) males die
much earlier than females do and (2) the costs of providing for a second mate
are too high for almost all males. In human hunter-gatherers, the ratio of men
to women on the mate market declines as one moves away from the equator. It
reaches its lowest point in open steppe-tundra environments, where almost all
food is obtained by men through hunting and where male mortality is high
because men have to pursue mobile herds of game over long distances in a cold
environment that offers few alternate sources of food.
Steppe-tundra covered most of northern and eastern
Europe during the Late Pleniglacial (25,000 to 10,000 BP). I use the term “last
ice age” in order to be better understood. There was a series of ice ages
during the Pleniglacial (70,000 to 10,000 BP), but modern humans had to adapt
only to the last one. To date, it looks like the most visible features of
Europeans (white skin, multi-hued hair and eyes) evolved during the time window
of the Late Pleniglacial. If the estimates by Beleza and Canfield are to be
believed, the time window is somewhere between 20,000 and 10,000 BP.
These estimates seem to conflict with the recent
findings of brown-skinned Mesolithic Europeans from Spain (7,000 BP) and
Luxembourg (8,000 BP). I would argue that the changes to hair, eye, and skin
color took place within a relatively restricted geographic area (essentially
the plains of northern and eastern Europe) and later spread outward. It’s silly
to argue that these changes must have originated in the Middle East, since the
Middle East was inhabited by an African-like population until at least 12,000
BP. This population (the Natufians) shows no biological continuity with later
Middle Easterners.
References
Beleza, S., Murias dos Santos, A., McEvoy, B.,
Alves, I., Martinho, C., Cameron, E., Shriver, M.D., Parra E.J., and Rocha, J.
(2013). The timing of pigmentation lightening in Europeans. Molecular Biology
and Evolution, 30, 24-35.
http://mbe.oxfordjournals.org/content/30/1/24.short
Canfield, V.A., A. Berg, S. Peckins, S.M. Wentzel,
K.C. Ang, S. Oppenheimer, and K.C. Cheng. (2014). Molecular phylogeography of a
human autosomal skin color locus under natural selection, G3, 3, 2059-2067.
http://www.g3journal.org/content/3/11/2059.full
Cochran, G. (2014). Shades of pale, January 27, West
Hunter
http://westhunt.wordpress.com/2014/01/27/shades-of-pale/
Frost, P. (2011). Hue and luminosity of human skin:
a visual cue for gender recognition and other mental tasks, Human Ethology
Bulletin, 26(2), 25-34. http://media.anthro.univie.ac.at/ISHE/index.php/bulletin/bulletin-contents
Frost, P. (2008). Sexual selection and human
geographic variation, Special Issue: Proceedings of the 2nd Annual Meeting of
the NorthEastern Evolutionary Psychology Society. Journal of Social,
Evolutionary, and Cultural Psychology, 2(4), pp. 169-191.
http://www.jsecjournal.com/articles/volume2/issue4/NEEPSfrost.pdf
Frost, P. (2006). European hair and eye color - A
case of frequency-dependent sexual selection? Evolution and Human Behavior, 27,
85-103.
Hoffecker, J.F. (2002). Desolate Landscapes. Ice-Age
Settlement in Eastern Europe. New Brunswick: Rutgers University Press.
Munitz, S., B. Priel, and A. Henik. (1987). Color,
skin color preferences and self color identification among Ethiopian and
Israeli born children, in M. Ashkenazi and A. Weingrod (eds.), Ethiopian Jews
and Israel. (pp. 74-84). New Brunswick (U.S.A.): Transaction Books.
Dr. Frost did you ignore the avalanche of genetic studies coming out on Europeans by Lazaridis et. al, Olalde et al. and others?
ReplyDeleteSo we now know that europeans are a mix of three diverged ancient populations: Early european farmers, Western hunter gatherers (who appear to have been brown, but blue-eyed) and Ancestral north eurasian.
How does this connect to your theory of hair/eye color diversification?
This theory makes pretty solid sense with respect to the Ethiopians. The politically-dominant Semitic-speaking groups like the Amhara have borrowed most of their belief system from the civilizations of ancient Yemen. This is how the Queen of Sheba legend became so integral to Ethiopian culture despite the fact that the Sabaean kingdom was situated on the Arabian side of the Red Sea.
ReplyDeleteThere doesn't seem to be an environmental impediment to having light brown skin at Ethiopia's latitude, provided it can tan deeply. Yemeni Arabs on the other side of the Red Sea - presumably closely related to the unmixed Semitic ancestors of the Amhara and Tigray - have much lighter unexposed skin than most Ethiopians. But it has a protective capacity to darken when people labor outdoors.
It would be interesting to know when exactly the SLC24A5 gene reached the Horn of Africa. It could certainly have done so around 3000BP with Semitic-speaking migrants from Arabia. But it's also possible that it happened several thousand years earlier via gene flow from North Africa (we know from their artwork that the Egyptians had acquired the deep-tanning light brown type of skin by the dawn of the Old Kingdom). This question may partly hinge on whether the non-Semitic branches of Afro-Asiatic evolved in Northeast Africa (as Greenberg hypothesized) or Southwest Asia.
Social selection for more Near Eastern-like traits might also help explain the prevalence of narrow noses and orthognathous traits among Ethiopians and Somalis - features that often make their skulls difficult to distinguish from those of North African/Mideast populations. There is, however, some evidence that these traits were present in East Africa much earlier - namely the Capsian remains found by Louis Leakey in the 1930s. Whether these people were migrants from Southwest Asia or locally-evolved ancestors of the long-faced Nilotic groups has always been hotly contested. In any event, they are now generally believed to be younger than the Natufians - and much younger than Leakey originally hypothesized.
Peter Frost you should not assume la Brana-1 and Loschbour had brown skin. It is not entirely known what causes European light skin. It could have become dominate separately all over Europe. The three main light skin mutations WE NOW KNOW ARE NEAR EASTERN NOT EUROPEAN.
ReplyDeletePeter for one think both Mesolithic Europeans tested for pigmentation genes(La Brana-1 and Loschbour) did not have A/A in SNP rs1426654(in gene SLC24A5) they had the ancestral alleles G/G. Both European farmers(Otzi early copper age 3,300BC and Stuttgart early Neolithic 5,500BC) had derived A/A alleles in rs1426554(in gene SLC24A5).
Loschbour(La Brana-1 may have been close) had 100% distinctfully European ancestry a form that laz 2013 found may only exist in Europe today. In northern Europe it is very high in at least north-eastern Europe Mesolithic ancestry is the majority.
Stuttgart and Otzi though had majority near eastern ancestry with some European hunter gatherer blood. Today rs1426654 A/A is just as popular in the near east as it is in Europe. This "light skin" mutations is near eastern not European.
It was probably first selected in the near east and spread to Europe with farming where it may have been selected again(in hyprid near eastern-European farmers). It is very popular in all west Eurasians. I think the reason why it is not around 99% in North Africa and south Asia could be because of non west Eurasian admixture.
I have not been able to read Olalde 2014 but I have hear la Brana-1 like Loschbour had none of the three main mutations associated with European light skin in genes SLC24A5, SLC45A2, and TYR. I have heard Otzi had SLC24A5 and TYR or SLC45A2 and I know that Stuttgart had SLC24A5 and TYR. Of course I am talking about the genotypes within those genes.
The only one of the three that is more popular in Europeans than in near easterns is rs16891982 G/G which according to SNPedia if Europeans have C/C they are 7x more likely to have black hair. Loschbour, La Brana-1, and Stuttgart had ancestral rs16891982 C/C.
Most Europeans don't have all three but most do have the ones in SLC24A5 and SLC45A2(except SLC45A2 is less popular in southern Europe).
All three of those light skin mutations are probably a sign of near eastern not European ancestry. THERE ARE OTHER FACTORS TO EUROPEAN LIGHT SKIN!!!!!!!!!!!!!!!!!!!!!!!!
The reason Europeans have light skin may be so complicated that it will never be discovered. I would bet you my life that a European with out any of those three mutations will have the same skin tone as an average person from his population. Same goes for Ethiopians with any of those three light skin mutations.
Peter, today light skin, light hair, and light eyes ALL correlate very well with Mesolithic European ancestry. Light hair almost always means light eyes and light skin. The three forms of paleness in Europe are almost always connected.
I don't see how mixing between light eyed-dark haired-dark skinned hunter gatherers and brown eyed-dark haired-and olive skinned farmers=blonde haired-blue eyed-north eastern European and Scandinavian. How did light eyes switch from being connected with dark hair-skin to being connected with light hair-skin?
La Brana-1 and Loschbour had very unexpected results and are hard to explain. One answer could be that Mesolithic west Europeans didn't survive well while Mesolithic east Europeans via Indo European and Uralic migrations did.
I think it is important to remember Neolithic northern European farmers(like Gok4) are not the main ancestors of modern ones. Same goes for Mesolithic north Europeans. It is much more likely Mesolithic east Europeans are the source of most hunter ancestry in modern north Europeans.
Peter where were near easterns ancestors 12,000 years ago? Hiding in some cave? Sure the Natufians biologically were not like modern near easterns. But Stuttgart is prove distinctfully near eastern ancestry existed there during the Neolithic. The European hunter gatherers originally came form the near east. Near easterns ancestors have been living there for over 50,000 years.
ReplyDeleteThat hypothesis you made before that near easterns descend from Europeans who migrated there 20,000 years ago it not true.
There is a perfectly feasible way to reconcile the fact that a) the genes for lighter skin originated among Neolithic farmers in West Asia, and b) that the lightest pigmentation is now found among the Europeans who derive the biggest chunk of their ancestry from the old hunter-gatherers.
ReplyDeleteIt is that once these genes got to Northern Europe, they were able to exert a more dramatic effect on phenotype than they did in the Near East, either because of less solar radiation or more aggressive sexual selection, or both.
Let's suppose a group of brown-skinned hunter-gatherers acquired the skin-lightening genes from olive-complexioned farmers somewhere in present-day Germany. Once these mutations percolated into Northern Europe, a selective sweep could have turned them pale between, 7000 and 5000 years ago. Because their environment allowed for fairer skin than the Mediterranean basin, they eventually became fairer than the population from which they derived the alleles in the first place.
Again, it's important to remember that were talking about a few genes, not the thousands of SNPs that distinguish the Mesolithic North European ancestral cluster from others. The bulk of those autosomal genes could have evolved locally in association with a very different phenotype.
We see this phenomenon in Northeast Asia. The Ainu are difficult to distinguish genetically from mainland Northeast Asians even though their phenotype is (or until recently was) drastically different from that of Koreans and northern Chinese. Evidently, the classic "Mongoloid" features depend on relatively few genes that arose after the Northeast Asian genetic cluster diverged from others. Presumably the Northeast Asian cluster was originally associated with an Ainu-like phenotype. So the Ancient North European cluster might likewise have once been associated with a look very different from present-day Icelanders or Finns.
What I think Peter is suggesting is that a selective sweep originating in, say, the highlands of Anatolia, Iran, or the Caucasus radiated outward in all directions with the spread of farming. If this is the case, the Natufians, like the European hunter-gatherers, may have contributed more to the overall genetic makeup of later peoples than their morphology would suggest.
"Once these mutations percolated into Northern Europe, a selective sweep could have turned them pale between, 7000 and 5000 years ago."
ReplyDeleteIf the studies saying the farmers and HGs hadn't mixed much by 4000 BC are correct that leaves c. 3,500 years for complete fixation even in the remotest mountain valleys before the Roman, Greek, Egyptian, and Chinese written records talk about red hair, light eyes and pale skin.
That sounds possible - just - but why the red hair?
And why does the red hair phenotype seem to have mostly disappeared in the interim, surviving mostly along the northwest fringe of Europe furthest from the farmer's starting point?
Red hair pigment is produced by a different gene or set of genes than blond/brown coloring. It's also supposed to date back further.
ReplyDeletePeople can carry the red hair gene without showing it because their brunet genes mask the rufosity. You need at least partial loss of brown-black pigment before you can really see its effects. Phenotypic "carrot-tops" would only have appeared after the diminution of brunet coloring.
In most cases where red hair was described in the ancient world, blond or light brown hair was noted as well. These traits spread rapidly during the Bronze Age primarily because the peoples who had them in high frequency were in often aggressive warrior nomads in possession of horses and chariots. The Indo-European nomads spread across the steppes all the way to Xinjiang - hence the light-haired Tocharian mummies. They also made episodic incursions into the Near East - hence the blond and red-haired Libyans on Egyptian wall reliefs.
Because red hair tends to be associated with very pale, freckling skin, it may have diminished in frequency in some areas due to people possessing it being at higher risk of skin cancer.
But just because classical writers took note of its presence in various populations doesn't mean it was in the majority. They simply payed special attention to it because it looked exotic. They were also using the description in a relative rather than an absolute sense. Red and blond hair were more common among Celts, Germans, and Slavs than among the Romans and Greeks themselves. It's just like the Herodotus quote about the ancient Egyptians that Afrocentrists always take out of context. What he meant was that they were comparatively darker and curlier-haired than the Greeks (just as Egyptians are today), not that they were literally black.
"Red hair pigment is produced by a different gene or set of genes than blond/brown coloring."
ReplyDeleteIt's not caused by a pigment. It's caused by a partial depigmentation i.e. it's a gene for dark hair that doesn't work.
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"It's also supposed to date back further."
Quite.
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"People can carry the red hair gene without showing it because their brunet genes mask the rufosity."
Yes, genes that add pigment override genes that don't work hence why genes for things like red or blond hair or blue eyes are effectively recessive as you need two copies to get the effect.
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"You need at least partial loss of brown-black pigment before you can really see its effects. Phenotypic "carrot-tops" would only have appeared after the diminution of brunet coloring."
Again it's depigmentation not a different pigmentation.
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"In most cases where red hair was described in the ancient world, blond or light brown hair was noted as well."
Which is what you'd expect from depigmentation.
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People keep talking about this like there are multiple airbrushes with different colors in them. White skin is (or at least can be) the *absence* of pigment not a different pigment.
So if you have genes that add a dark pigment to hair, eyes and skin you don't need genes that add different pigments to create light hair, light eyes and light skin - you just need mutated version of the same genes that don't work.
Which is why - if it was advantageous - it would have been much faster for Europeans to become lighter through this form of loss of function partial albinism.
It's not caused by a pigment. It's caused by a partial depigmentation i.e. it's a gene for dark hair that doesn't work.
ReplyDeleteWrong. Red hair is caused by pheomelanin.
Anonymous,
ReplyDeleteI am not nearly as good at writing my thoughts as you are. You described(in your first post after my last post) what I have been thinking for a while. There are still some things which are not constant with that hypothesis.
>We no one fully knows why Europeans are so pale skinned!! The three mutations Peter keeps mentioning are near eastern not European. Only s16891982 G/G(in gene SLC45A2) is more popular in Europe than in the near east. Actually it is dominate in Europe and if a European has C/G or C/C SNPedia states he/she is 7x more likely to have black hair.
>La Brana-1 and Loschbour may have had the real mutations(or whatever causes it) for European light skin.
>light hair almost always means light eyes their distribution is connected same with the distribution of light skin in Europe. Mesolithic west Europeans La Brana-1 and Loschbour had light eyes ad black(maybe brown) hair, which is surprising.
>Light hair-eyes-skin correlate very well with Mesolithic ancestry and skull shape.
Made by Fanty
http://img1.picload.org/image/lroorlw/whg-stuff.jpg
>Modern north Europeans are probably not mainly descended from Neolithic farmers of northern Europe(Swedish Funnel beaker farmers are prove for at least Sweden), or Mesolithic north Europeans(Loschbour, Motalas, Gotland hunter gatherers, mtDNA from Karelia all evidence). Instead may be mainly descend from Indo Europeans and Uralics who got their WHG from far eastern Europe. Of course there may be some Mesolithic and Neolithic north European ancestry left and Mesolithic north-east European may have survived very well. So the paleness may be from Mesolithic or Neolithic east Europeans.
>Where did the mutations for light and red hair come from? They are close to non existent in Sardinians(nearly identical to Stuttgart and Otzi). Why are north Europeans eve paler skinned than Sardinians? Maybe there are unknown reasons which came from the hunter gatherers.
Mesolithic (west)Europeans did not have any of the three most strongly associated mutations with Euro light skin and all were brought with farming from the near east. If modern Europeans have so much WHG ancestry and for some it is majority why are these mutations just as popular or more so than in Neolithic Europeans and modern near easterns? I think selection could be a reason looking at their percentages in mixed near eastern and south Asian or sub Saharan African populations can tell whether it became dominate in hyprid European-near easterns by selection.
The selection stuff makes sense but I think it may be more complicated. The only real way to solve this is more ancient DNA. In my opinon light hair and skin(we know light eyes already existed) may be of Mesolithic European origin or from hybrid hunter(WHG and ANE) and EEF people.
ReplyDeletePigmentation genes from Andronovo people in Siberia from 1,800-1,400BC show they were mainly blonde haired and light eyed. Actually samples of Indo Iranians spanning almost 2,000 years from ~1,600BC-~300AD their hair and eye color are very close to modern north-east Europeans and Scandinavians. There is only one sample labeled as dark brown haired and that same sample was showed to have mainly east Asian ancestry. They were an extremely fair people.
They had migrated there from modern day Russia. Probably had that pigmentation all the way back to at least 3,000BC. The Corded ware people(who were dominated by a brotherclade in R1a) were also probably mainly light haired and eyed. The Rise project will probably prove those features had reached modern north-east European and Scandinavian frequencies by at least 3,000BC.
I doubt blonde hair went from 0% in 6,000BC to over 60% in 3,000BC or even 4,000-5,000BC. It had to of existed in either the near eastern farmers or European hunter gatherers. Today almost every person with blonde hair has blue eyes. And we know the hunter gatherer also did.
It doesn't make sense that at the most far north-east Europeans are something like 50-70% Mesolithic European descended. Yet they have close to 90% light eyes. Did those features become selected after farmers and hunter gatherers mixed? That makes sense to me unless east European hunter gatherers were 100% light eyes which is very unlikely.
I think the two features that haven't been found in hunter gatherers light skin and light hair probably did become more popular in some population during or after the Neolithic.
It's not caused by a pigment. It's caused by a partial depigmentation i.e. it's a gene for dark hair that doesn't work.
ReplyDeleteTechnically, the reason why red hair is red is that it contains a higher ratio of pheomelanin pigment ("twilight melanin" - which reflects mainly red light and absorbs other wavelengths) to eumelanin (which reflects and absorbs the spectrum evenly).
However, the absolute amount of melanin in red hair (pheomelanin + eumelanin) is in fact lower than blondes (or at least, all but the whitest haired of blondes). So it is correct to say depigmentation is the reason.
So redheads are both more depigmented in hair relative to other folks (not surprising given they are the lowest for skin pigmentation) and have different pigmentation.
Re European changes on OCA2 (and pigmentation in general), one of the elements I've found interesting is that Europeans have less albinism than other populations. Albinos having many problems with deafness and so on, which would have a clear fitness hit.
So there might have been natural selection for a variant of OCA2 whose descendants aren't likely to mutate into albinos. And this variant could've been a "stable depigmented" variant. Like, if you have a variant that's awesome, but a lot of its descendant variants are f*cked up, then selection could ultimately favor the less awesome variant.
Men tend to die younger than females and the population where this phenomenon is most pronounced (as now) is Russia, where men tend to die young. By coincidence, or not, Russian girls are very white and very beautiful.
ReplyDeleteThe cause of the scarcity of Russian menfolk is violence, caused by wars (in the past) and alcohol.
Alcohol, may be, has something to do with the whitening of the northern peoples.
I have no references to support this idea.
"Wrong. Red hair is caused by pheomelanin."
ReplyDeleteIt's not caused by increasing Pheomelanin it's caused by *reducing* the regular amount of Eumelanin i.e. partial de-pigmentation.
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"I doubt blonde hair went from 0% in 6,000BC to over 60% in 3,000BC or even 4,000-5,000BC. It had to of existed in either the near eastern farmers or European hunter gatherers."
De-pigmentation can be additive.
Light eye color is (mostly) not a pigment it's lack of melanin so if you add extra de-pigmentation genes to someone who already has grey or green eyes they turn blue.
Similarly if you add extra hair de-pigmentation to someone who already has light hair then it can turn blond.
So say the WHG were originally South Asian looking but at some point started to look like this.
http://25.media.tumblr.com/tumblr_lznk2olY6A1r8vrhxo1_500.jpg
and then the IE added genes that added *extra* de-pigmentation to both hair and eyes then red hair turns blond and grey or green eyes turn blue.
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"So redheads are both more depigmented in hair...and have different pigmentation."
Yes, I tend to oversimplify.
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"Re European changes on OCA2...one of the elements I've found interesting is that Europeans have less albinism..."
Yes. To me that would fit with Europeans going the partial albino route first - for the UV - because it was fastest and then working back from there to clear the negative aspects with the changes to the SLC genes being one of those improvements.
Spageti,
ReplyDeleteYes, I have been following the "avalanche" with keen interest. The main problem is that many of the mtDNA haplotypes in question are not selectively neutral. This is particularly the case with haplogroup U, which is linked to body heat production. Farmers have a very different profile of heat production than do hunter-gatherers. They are more sedentary and less prone to expenditure of energy in sudden bursts. The virtual disappearance of haplogroup U was probably due to natural selection for a different regime of heat production and expenditure.
This was confirmed by Melchior's study in Sweden. The genetic transition took place not only between late hunter-gatherers and early farmers, but also between early farmers and somewhat later farmers.
We also see the disappearance of haplogroup U in areas where the archaeological record shows cultural continuity during the transition to farming. In some areas, farming was adopted in proto-historic times, such as by the Finnish and Baltic peoples. These groups are clearly descended from indigenous hunter-gatherers, yet they look little different from other populations of northern Europe.
I don't doubt that there was a movement of farmers into Europe, but the evidence for population replacement is only strong in central Europe. Even there, the "replacers" themselves seem to have been replaced not long after. Moreover, these Middle-Eastern farmers seem to have been recent European immigrants to the Middle East who displaced the Natufians around 12,000 years ago.
Barak,
So you're saying that these Mesolithic hunter-gatherers became fair-skinned in a way completely different from that of other Europeans. And this other way has completely disappeared since then.
Sounds like Occam's chainsaw massacre.
Wouldn't occam's chainsaw massacre be a better name for an extremely precise and to the point use of occam's razor, literally a theory with the minimum detail adhering to all facts and possiblities. Like, holy shit, that guy just Occam Chainsaw Massacred the other debator. Or Copernicus Occam Chainsaw Massacred the heliocentrists.
ReplyDeleteI think a much better sarcastic term is Steve Sailer's Occam's Butterknife, which implies an ineffective and harmless kitchen cutlery.
So you're saying that these Mesolithic hunter-gatherers became fair-skinned in a way completely different from that of other Europeans. And this other way has completely disappeared since then.
ReplyDeleteBeleza et al 2013 (skin color genetics in Cape Verde) leaves substantial unexplained variance. And East Asian skin color is unexplained.
It's not necessary for any difference to have "disappeared", but the alleles we know about may explain less than we think.
People need to stop to think '' humans change of the environment and mutations happens''. Don't there a causal explanation to mutations, it simply happen. Why there albino people?? Why there the albinos in many other species?? The order of things need to be inverted,
ReplyDeletepeople with mutations change of the environment, light skinned ones move to tempered climate or mountains and not, people on tempered climate suffer mutations, adaptative or not. Seems lamarckism process.
Albinos are only ''error'' or extreme mutation, without any aparent effect to adaptation. Light Skinned, in my opinion, derivative to 'albino mutation spectrum', also do not have any aparent effect. If there light skinned people with intolerance to lactase, so, the effect of light skin to its kind of adaptation is not causal. If there dark skinned people that do not have intolerance to lactase, so, skin color and milk adaptation is not causal. Should be, more light skinned people developed mutations to adapt to milk drinking but, on a type of social environment in tempered areas, people with light skinned tend to be more cooperative, introvert and more conscious. So, by the social necessity of this kind of tempered areas need, the people with less of this traits of personality was less selected.
10.000 anos before, i believe that human beings already could thinking like a modern animal.
Asian light skin was developed like any mutations, without a linear causal explanation.
Dr. Frost, since I am Turkish, that must mean my ancestors migrated from the arctic 15,000 years ago!! That is amazing and something I did not know, although I will have to wait and see for verification. I always thought I was a dark, squat, Mediterranean sand-nigerino but apparently I am an arctic warrior.
ReplyDeleteTruth be told I would have preferred if they had stayed in Europe. Idiots.
The sexual selection theory has one annoying embedded feature: it applies to hunter/gatherers living in difficult conditions, per definition, and that means that whatever they select for, their numbers will stay small.
ReplyDeleteTherefore the population's densities are a strong constrain in Peter's theory and that must constrain the Time necessary to spread these genes in return.
The fact is that if we can still find 7000 years old individuals who still have a dark skin, the small number of white skin genes have still had not enough time to spread to the entire European population, i.e, Europeans are too dispersed, but again, it's what you expect from a population of hunters gatherers, by definition.
And even Otzi the 5000 years old iceman, wasn't he also sort of bronze-skinned?
Now we are 5000 bc and these genes havn't still made it to the entirety of Europe.
But the clock is ticking. By the time of Julius Cesar, Gaul was populated by 10 millions white skinned celts.
How do you jump from a population of few hundred thousands heterozygous individuals, to an homozygous population of 10 millions in barely 5000 years?
Is it even possible with sexual selection only?
"How do you jump from a population of few hundred thousands heterozygous individuals, to an homozygous population of 10 millions in barely 5000 years?
ReplyDeleteIs it even possible with sexual selection only?"
It might have sped up the spread of partial albinism (the red hair phenotype) - if that is what happened.
Spageti,
ReplyDeleteA razor makes a sharp surgical incision. A chainsaw massacre makes a bloody mess.
Anon,
East Asian skin color followed a different evolutionary trajectory, probably because East Asians were reproductively isolated from Europeans with the onset of the last ice age around 25,000 to 20,000 years ago.
If Western European hunter-gatherers evolved an alternate form of skin depigmentation, I would expect to find some traces of it today. It's not as if they were an isolated population in the middle of the ocean. They were a subpopulation within Europe.
Gottlieb,
Yes, mutations happen randomly all the time, but some kind of selection is needed to make them more and more prevalent. Otherwise, they will remain rare oddities, as is the case with albinism (although the rate of albinism is unusually high in some societies, apparently because of some kind of social selection).
Spageti,
The Middle East seems to have been inhabited by an African-like population until 12,000 years ago. It was replaced by a population of European origin (although this replacement may have happened earlier in present-day Turkey). If we look at ancient DNA from Tell Halula (9,000 years ago) in northern Syria, it looks mainly European with some sub-Saharan lineages.
The word "Turk" is a political/historical construct. Before the 1920s, it was somewhat pejorative and most Turks preferred to call themselves "Ottomans" or simply "Muslims." Most of the Turkish population is ultimately of European origin, and a large proportion is of recent European origin, i.e., less than one thousand years ago. Large numbers of Christian Europeans "turned Turk" or were forcefully brought to Turkey as slaves or concubines.
Ben,
First, the European steppe-tundra had high bio-productivity and a correspondingly large human population. There is no comparison with present-day steppe-tundra, which is farther north and much less productive.
In any case, I don't follow your reasoning. A low population density would be a constraint on the production of mutant alleles, but it would not constrain selection for these alleles. Nor would it impede the spread of new mutant alleles. This was a highly mobile and large panmictic population, so new alleles would have spread rapidly.
Did Otzi have brown skin? As I remember (I don't have the reference at hand), Otzi had the 'European' allele for SLC24A5.
Finally, it's easy to go from a few hundred thousand to ten million in 5,000 years. Only 10,000 French immigrants came to New France, and now their descendants number at least 10 million in Canada and the United States.
"If Western European hunter-gatherers evolved an alternate form of skin depigmentation, I would expect to find some traces of it today."
ReplyDeleteYes, and if it existed - and it is only an if - and there were any surviving traces they would only likely be found the furthest away from the farmer's start point in Southeast Europe i.e. somewhere in the northwest corner - like Ireland, Scotland, Norway etc or remote clusters of their diaspora in Anzac or the US.
.
"he main problem is that many of the mtDNA haplotypes in question are not selectively neutral. This is particularly the case with haplogroup U, which is linked to body heat production."
Another possibility for the increase of mtDNA H after the collapse of LBK might be to do with the spread of SLC24A5 via the remaining LBK females i.e. neither the HGs or IE had it before they over-ran the LBK.
"...Nor would it impede the spread of new mutant alleles. This was a highly mobile and large panmictic population, so new alleles would have spread rapidly"
ReplyDelete'Rapidly' but not everywhere, since this 7000 years old European guy still didn't have a white skin and 5000 bc is pretty late.
"Did Otzi have brown skin?" Wikipedia says he was similar to southern Europeans.
"Finally, it's easy to go from a few hundred thousand to ten million in 5,000 years. Only 10,000 French immigrants came to New France, and now their descendants number at least 10 million in Canada and the United States"
Not so fast. The French immigrants were farmers with families of 8 kids. Typically not the kind of environment where you theory applies.
Actually you have not mentioned that point: what happen when farming came to the Europeans? did the sexual selection for white skin relaxed completely, or did it continue as strong as before?
7000 years ago, What would forbid the Europeans with dark skin to have 8 kids as well?
If Western European hunter-gatherers evolved an alternate form of skin depigmentation, I would expect to find some traces of it today. It's not as if they were an isolated population in the middle of the ocean. They were a subpopulation within Europe.
ReplyDeleteMy point here isn't related to East Asians.
It's that if a lot of the skin color difference between Europeans and Africans is unexplained, and we have ancient populations who are more "European" than any recent population, they could have some "fairness" alleles at higher frequency than modern populations (even if this doesn't make them fairer overall).
''Gottlieb,
ReplyDeleteYes, mutations happen randomly all the time, but some kind of selection is needed to make them more and more prevalent. Otherwise, they will remain rare oddities, as is the case with albinism (although the rate of albinism is unusually high in some societies, apparently because of some kind of social selection).''
Yes i know but i'm not talk about the process, like you said, mutations are aleatory. What i try to explain, my opinion, is, the order of events seems misunderstood by many people, is not metamorphosis based on adaptation but only, selection, darwinian way of life.
Therefore, don't there ''people migrated by area X to area Y and mutations happen'', but people with mutations or mutants (people with aparent mutations like albinos and not father of albino kid with one of the two pairs of genes) migrated to...
Adaptation is like instinct, desire to live, when my skin is very sensible to sun of this land, i will search the land where i not die with skin diseases.
"So you're saying that these Mesolithic hunter-gatherers became fair-skinned in a way completely different from that of other Europeans. And this other way has completely disappeared since then.
ReplyDeleteSounds like Occam's chainsaw massacre."
What I am saying is whatever really causes true European light skin(not what you see in the near east) has not been discovered and may have existed in La Brana-1 and Loschbour. The real cause(or all the causes) to creating European light skin(especially in the most Mesolithic descended region which is northern European) has(or have) not been discovered.
There are three mutations most associated with European light skin and you mention them oftenly. The problem is all of them are just as popular in very brown skinned near easterns as they are in snow white Baltics, except for rs16891982 G/G or G/C(in gene SLC45A2)which is 100% in CEU(I think Utah white Americans) and the vast majority is G/G while a small minority is G/C. I have a distribution map of it and in a few populations in southern Europe are around 50-60% but in almost all Europeans it is close to 100%. According to SNPedia if a European has G/C or C/C they are 7x more likely to have black hair. I don't know how these genes work but are they connected skin and hair pigmentation?
Still rs16891982 G/G or G/C(in gene SLC45A2) is around 50% in near easterns. The mutation in gene TYR is not even 50% in most European populations and is just as popular in near easterns. I doubt it makes a big effect on skin color.
Maybe rs16891982 G/G or G/C(in gene SLC45A2) makes a big effect on skin color but that's all I can think of. Why are northern(most Mesolithic) Europeans lighter than southern(more near eastern) Europeans and why are near easterns much darker than both if they all have basically the same percentages of these "white skin" genes? Obviously there is some unknown reason.
No offense Peter, but you can forget all those age estimates for the three main white skin mutations because their not European and they don't cause white skin. We now have prove in ancient DNA that it was near eastern farmers who brought those mutations to Europe. They cause skin to be paler but how much paler black to dark brown? You cant explain the light skin in Europe with those mutations.
Peter this is a continuation of my last post about why all the causes of European light skin have not been discovered. Here are some more reasons why I think La Brana-1 and Luschbour's skin color is unknown and why it is inaccurate to call them brown skinned.
ReplyDeleteMaju agrees
http://forwhattheywereweare.blogspot.com/2014/01/la-brana-1-carried-very-rare-y-dna.html?showComment=1391020766375
Like I said in my last post we now know through ancient DNA all three of those mutations are near eastern not European. We also know that blue eyes and black hair(probably also brown) existed in Mesolithic (west)Europe and were popular.
Here are some things that are hard to explain if you believe Mesolithic Europeans were brown skinned and blue eyed(WHAT!!). It gets very annoying when people ignore these facts. Trust me pigmentation genes from more Mesolithic European especially eastern and blonde hair will pop up. Which would be great evidence they did not have dark skin.
>Today light hair-eyes-skin have very similar distributions in Europe. The lighter haired and eyed people are also the lighter skinned people.
>In Europe today generally the lighter the hair the lighter the eyes. If you have blonde hair there is close to 90% chance you will also have light eyes. If you have black hair you most likely(over 60%) will have brown eyes.
>Today Mesolithic European ancestry almost perfectly correlates with light eyes. It also is very similar to the distribution of light hair(maybe not counting Insular Celts who have ~40% light hair including 10-15% red but also have close to 80% light eyes) and light skin.
>The most Neolithic or just near eastern descended Europeans have vast majority dark hair, dark eyes, and also have darker skin than more Mesolithic descended Europeans. Sardinians who are nearly perfect matches to early European farmers have the lowest amount of light hair and eyes in Europe.
Peter could you explain how blonde hair descends from near eastern farmers(many think so) if nearly 90% of modern blondes have light eyes? We know the farmers were brown eyed and the hunter gatherers were blue eyed(of course not 100%). How do you explain redheads also have overwhelmingly light eyes and how that could be descended from near eastern farmers? So if you agree both blonde(aka light) hair and red hair existed in Mesolithic Europe how could they also have had a deep shade of brown skin?
Trust me I know redheads are the palest(non albino) people on the planet. When I compare my skin to other white people theirs looks brown. Our skin is literally white and can barely tan.
It is not just random that Mesolithic ancestry correlates with light skin-hair-eyes. If blonde hair, red hair, and light skin originated in Neolithic Europeans why aren't southern Europeans(especially Sardinians) full of it?
I guess you could say that for some reason the Neolithic ancestors of north Europeans got light skin from the farmers and brought to a new extreme(through unknown mutations) kept the light eyes of the hunter gatherers and developed light hair which became very popular and for some reason connected with the light eyes of the dark skinned hunter gatherers.
We know Neolithic Swedish are not the ancestors of modern ones(at least not even close to majority). They had little difference with modern Sardinians, Stuttgart, and Otzi. It makes sense all Neolithic north-west Europeans were like that. Maybe a mass migration of very pale people from eastern Europe(Indo Europeans and Uralics) spread their features during the metal ages. Maybe north-east Neolithic Europeans developed extreme paleness during the Neolithic. While south Europeans have other forms of Neolithic ancestry and have the pale(not as pale) skin and almost no light hair and eyes.
Peter could you please give me a logical explanation for why pale skin and light hair developed during the Neolithic?
"Beleza et al 2013 (skin color genetics in Cape Verde) leaves substantial unexplained variance. And East Asian skin color is unexplained.
ReplyDeleteIt's not necessary for any difference to have "disappeared", but the alleles we know about may explain less than we think."
Exactly for this reason I think Loschbour and La Brana-1 should be classified with unknown skin color.
Ben,
ReplyDeleteBy "brown" I don't mean the olive skin of many southern Europeans. I mean chocolate brown. Razib (who is of Bengali origin) pointed out that these Mesolithic Europeans were darker-colored than he is.
Sexual selection relaxed considerably, but not completely after the last ice age (there is always some degree of sexual selection). The period of intense sexual selection ended when the steppe-tundra disappeared from Europe.
Barak and others,
Ancestral Europeans went through two stages of skin lightening: a first stage around 30,000 years ago, which involved the gene KITLG, and a second stage around 19,000 to 11,000 years ago, which involved the genes TYRP1,SLC24A5, and SLC45A2. The first stage may have been an adaptation to weaker sunlight. The second stage was part of a larger phenotypic change that was driven, I argue, by sexual selection. You're free to disagree with me on the causation, but this timeline of pigmentary change is what the current evidence tells us.
Both you and anon raised the point that we have not located all of the genes responsible for the difference in skin color between northern Europeans and West Africans. True, but that difference encompasses at least three evolutionary events: the two stages of depigmentation in ancestral Europeans and the darkening of West Africans from a more Khoisan-like ancestor. I'm only talking about the depigmentation that happened in Europe between 19,000 and 11,000 years ago, and that difference is explained by allelic changes at three genes.
There is a tendency in this debate to see "Europeans" as a homogeneous entity. If Mesolithic Europeans were brown-skinned in Luxembourg and Spain, they must have been brown-skinned all over Europe. Therefore, according to this argument, white skin must have initially appeared outside Europe. I think it's more likely that white skin first appeared in northern and eastern Europe and later spread to the rest of the continent and then beyond.
Peter I don't understand why you think mutations in SLC24A5, SLC45A2, and TYR=snow white north European. We know it doesn't because Iraqis have the same amount of these mutations except for the one in SLC45A2 which is around 50% in the near east and 100% in most of Europe. The one in TYR doesn't even reach 50% in Europeans and is just as popular in near easterns. These mutations are near eastern not European and ancient DNA has proven that.
ReplyDeleteDid you even read the evidence that I gave? You keep pushing this 11,000-19,000ybp stuff. You base on age estimates(who knows how accurate) on three mutations that may only cause a little paling of European and near eastern skin.
How would Razib know what skin color La Brana-1 and Loschbour had? Does he have a time machine? No so he doesn't know what their skin color was. People have to much faith in these three mutations.
I think you are making an assumption west Africans went from Khosian bronze to what they are now. Papuans who are east Eurasian have just as dark skin as almost all sub Saharan Africans. If anything I think the ancestors of all humans over 100,000 years ago had the skin color of west Africans or darker.
Can you please read my previous post. It seems you don't consider who lived where at what time. For example Neolithic farmers of Sweden were most related to Sardinians and Basque not the main ancestors of modern Swedes. So just because farmers in northern Europe today are very pale and Mesolithic like doesn't mean they were in the Neolithic. There has been a lot of population change in Europe since the Neolithic.
@barak
ReplyDelete"The real cause(or all the causes) to creating European light skin(especially in the most Mesolithic descended region which is northern European) has(or have) not been discovered."
I think they likely have been discovered but they won't be noticeable except in rare individuals.
If MC1R or IRF4 have a depigmentation effect but everyone who's been studied *also* had the other skin lightening alleles then how would you know they had that depigmentation effect?
(Actually you probably would because people like that almost certainly have disproportionate skin problems in places like Australia.)
That those genes have a depigmentation effect would only be obvious in individuals who have them but not the SLC ones i.e. they'll be just as white without them - or more likely **whiter** like the almost translucent Scots you see if you've ever spent time in a Scottish regiment.
.
(obviously whatever the cause of the initial lightening it doesn't effect whether or not it spread by sexual selection after)
You do have to admire Frost, he keeps pushing his theories even though the recent evidence makes them a lot more unlikely than other theories.
ReplyDeleteWelp, we'll see with more data.
http://www.youtube.com/watch?v=UI2cNs6m4cQ
ReplyDeleteSkin color in chimps is probably almost completely unrelated to skin color in humans. There could be a number of reasons why many have pale pinkish skin under their fur.
ReplyDeleteI know that Loschbour had rs12203592 T/T(in IRF4 gene) and I have heard La Brana-1 did to. I also know the mutation is associated with sensitivity to the sun, freckles, and brown hair. I have no idea how it works and if it really makes a big effect on pigmentation. Since Loschbour and La Brana-1 were missing both SLC(TYR is at highest 50% in Europe and near east) means mutations in IFR4 doesn't effect the same way.
In the 8-plex eye color predictor if some one has rs12913832 G/G(in gene OCA2/HERC2) and rs12203592 T/T(in IRF4 gene) they have blue eyes. If someone has those two plus rs16891982 they are green eyed. Loschbour fits as blue and green eyed.
According to SNPedia rs12203592 T/T(in IRF4 gene) is very rare in CEU(Utah white Americans) combined with C/T it is maybe around 30%. I think their CEU are samples from white Utah Americans so probably mainly north-west European. Both T/T and C/T existed in Tuscans Italians, Mexicans, and African Americans from south-west USA. Mexicans(get it from Spain) and African Americans(get it from Britain) probably get it originally from Europe.
There's a new study in "Nature" by Benjamin Vernot and Joshua Akey suggesting that "Neandertals were a source of adaptive variation for loci involved in skin phenotypes" in Eurasian populations.
ReplyDeleteNot sure what genes they're referring to. But such an admixture event would obviously antedate the Mesolithic hunter-gatherers by tens of thousands of years. If Neanderthal admixture contributed to de-pigmentation in modern Eurasians, the process must have begun at least as early as the entry of Cro-Magnons into Europe, and possibly as early as the first modern forays into the Mideast and Central Asia.
I doubt the Neanderthal thing I think they were talking about east Asians.
ReplyDeleteI have read Peter many times associating all forms of paleness in Europeans with women. He has made the point many times those features became popular because of sexual selection towards women.
Every statistic I have seen comparing hair and eye color between men and women isn't constant.
http://blogs.discovermagazine.com/gnxp/2007/07/how-swarthy-are-the-sami/
http://www.haar-und-psychologie.de/haarfarben/hair-colors-eye-colors-germany.html
There was another study on Icelanders and Ducth. Every single one(even the one form the 1930's) showed that women have a higher percentage of brown eyes, men have a higher percentage of blue eyes, and women a higher percentage of green eyes. It seems men may also have a higher percentage of blonde hair than women. I think many Americans assume more women have natural blonde hair because so many dye their hair blonde. Hair color statistics should be taken at a young age because hair color gets older with age, it may effect one gender more than the other.
" If Neanderthal admixture contributed to de-pigmentation in modern Eurasians, the process must have begun at least as early as the entry of Cro-Magnons into Europe, and possibly as early as the first modern forays into the Mideast and Central Asia."
ReplyDeleteI was wondering if the admixture might be that early but different aspects of it were differently selected for or against over time.
For example, straight hair and depigmentation alleles from early on but the depigmentation alleles mostly selected against *until* they reached further north.
@barak
ReplyDelete"Skin color in chimps is probably almost completely unrelated to skin color in humans. There could be a number of reasons why many have pale pinkish skin under their fur."
There's no need for pigmentation under fur. White skin isn't a pigment it's a lack of pigment.
.
"According to SNPedia rs12203592 T/T(in IRF4 gene) is very rare in CEU(Utah white Americans)"
If the SLC genes were an improvement over the early depigmentation method (if it existed) then you might expect the frequencies of IRF4 and MC1R to have gone down.
http://www.youtube.com/watch?v=UI2cNs6m4cQ
ReplyDeletewow, without the fur you can really see the muscle on them
conan the chimp
Almost every week now I've regretted the tone I took with Chris Crawford back when he was a regular here. It used to be you could read comments by impressive people who, even if they disagreed with the post were not dogmatists who thought they knew it all. Come back Chris.
ReplyDeleteBarak,
ReplyDeleteIt's not enough to reject evidence you don't like. You have to provide reasons why you reject that evidence.
I disagree with the evidence that most of the European gene pool comes from Middle Eastern farmers. In my opinion, this evidence is flawed because it rests on the assumption that the haplogroups in question are selectively neutral. They aren't, particularly in the case of haplogroup U. We also have good archaeological evidence for cultural and biological continuity in many régions of Europe, particularly those where the transition to farming took place in proto-historic times.
Yes, all of this makes me an outlier, but at least I'm justifying my position.
In the case of the whitening of European skin color, we have estimates from two research teams (Beleza and Canfield) that closely agree with each other (as well as an earlier effort by Heather Norton). These estimates may be wrong. Perhaps the methodology was unsound. Perhaps the data were not representative. But you cannot just wave your hands and make that evidence go away simply because you don't like it.
Peter, those three mutations are not the only things whiting European skin plus they are near eastern not European. That's why I don't trust the age estimates. Stuttgart is good evidence those age estimates still may be young. I bet genomes from the near east dating back even 15,000 years ago will have rs1426654 A/A(in gene SLC24A5) and maybe the others.
ReplyDeleteSo we know light eyes were probably pretty popular in Mesolithic (west)Europe but why are they still popular today in hybrid European-near eastern-ANE people. Swedish-Norwegian-Finnish have over 85% light eyes and ~72% blue eyed yet Swedish-Norwegian score ~42% WHG, ~40% EEF, and ~16% ANE. Finnish score ~47% WHG, ~33-34% EEF, and ~18-19% ANE. Both have a very high amount of Stuttgart related ancestry but then why are they dominated by hunter gatherer light eyes? Irish are even a better example they have around the same eye color as Scandinavians but have much more EEF than WHG.
Why is rs1426554 A/A dominate in Europe today if so many have high amounts of Mesolithic ancestry? Why is rs16891982 G/G or C/G(in gene SLC45A2) so dominate in Europe today and less popular than the near east which is where it probably originated and spread from. Is selection the reason for all of this. Did it happen separately across Europe?
"I disagree with the evidence that most of the European gene pool comes from Middle Eastern farmers. In my opinion, this evidence is flawed because it rests on the assumption that the haplogroups in question are selectively neutral. They aren't, particularly in the case of haplogroup U. We also have good archaeological evidence for cultural and biological continuity in many régions of Europe, particularly those where the transition to farming took place in proto-historic times.
ReplyDelete"
Peter, the fact is that the vast majority of European mtDNA no matter where in Europe is of near eastern origin. Sami and other ethnic groups may be acceptations because of founder effects(mtDNA V is probably not native to Europe). There were many subclades of mtDNA haplogroups which were found to be exclusively European so people assumed they had been there since like the Upper Palaeolithic because of age estimates. Now we know though that all of those haplgroups came to Europe from the near east with farming. H1 and H3 seem super European but they are not.
We now that mtDNA U5 and U2 have been in Europe for over 30,000 years and also U4 has probably been in Europe since the Upper Palaeolithic. Combined these haplogroups reach at average 15% or so in Europe.
Laz 2013 proved most Europeans have mainly near eastern ancestry. The only places you may find mainly Mesolithic ancestry are in north-eastern Europe and Scandinavia. Who knows hunter gatherer ancestry may be higher that WHG-EEF-ANE thing estimates. Plus there is some WHG in EEF.
@barak
ReplyDelete"Laz 2013 proved most Europeans have mainly near eastern ancestry."
He didn't show that at all.
WHG + c. 90% of ANE + c. 50% of EEF is "European."
Personally i wouldn't call it European yet but Hyperborean (or some other suitable word for the crescent of land from Europe to Siberia that made up the mammoth steppe.)
Europeans are more like what's left of the Hyperboreans.
Well, that's the problem with Frost's theory, isn't it?
ReplyDeleteThree points that contradict each other:
1) earliest farmers migrating to europe from near-east had european version of SLC24A5.
2)These farmers were later partly replaced by people more similar to mesolithic europeans hunter-gatherers, who according to the Lazaridis paper, had the ancestral version of the SLC24A5 gene. Both Loschbour, and La Brana. Separated by about 1,000 years and from different parts of europe, north Spain and Netherlands.
3) There is no evidence that modern near-easterners are descended from back-migrants from Europe.
So either separate light-skin mutations happened in the tundra steppe and the near-east, or the mutations is significantly older than 19,000 years.
The thousand years or more of primogeniture and monogamy in Europe presumably also led to sexual selection of females with the first born having the pick of the brides. I remember reading about how European skulls have gotten more neotenous over the course of the medieval period. When the Pope compared the Angles to Angels perhaps that was just in comparison to others who where still relatively ugly at the time so Angles would not look the special to us today. Selection for female traits would create a more domesticated population primed for modernity.
ReplyDeleteFemale selection is not the answer for everything!!!!!!!!!!!!!!!!!!!!!!!!
ReplyDeleteI am getting sick of hearing about it. Women are more brown eyed and green eyed than men and from what I read hair color percentages are pretty even. People assume light hair and eyes are feminine traits probably because of our culture. I doubt the same stero types will be shown in all ancient writers. From what I have read from ancient Romans and Greeks where eye and hair color is mentioned they never associated any with males or females it was just different hair and eye color. A Lithuanian told me in his country the style is for women to dye their hair black and tan their skin. That's kind of the opposite from America but what it shows is paleness is not always associated with women.
Are pale women like 1,000 times more attractive? Why would over 1,000's of years European men keep overwhelmingly pick fairest women? It seems unlikely to me that selection of pale women is the answer.
Peter you keep mentioning baby like faces in Europeans what do you mean? I have never noticed that. Its okay to think of other possibilities besides female selection. You also have to consider who certain Europeans descend from. Whatever pigmentation changes occurred in pre Neolithic Europe should have little effect on southern Europeans. You should definitely not except Greeks or Sardinians to have these baby faces.
@barakobama
ReplyDeleteStudies on EYE color in European /African admixed populations have shown NO correlation with either overall genetic ancestry or skin color (when the known alleles causing the color changes are excluded from the analysis).
The entire basis of your argument stems from the fact there are not existant populations with light eyes and dark skin (besides those with recent admixture). Therefore, you suggest that these West Eurasian hunter gatherers must have had light skin. This is despite the fact that they do not have the alleles with the strongest signals for light skin, as revealed in numerous studies.
Clearly, there is evidence that many additional loci have small additive effects on this trait, and these additional alleles are present in the genomes of modern light-skinned Europeans. However, there is absolutely no evidence that these missing loci originated in the Mesolithic European hunter gatherers, or are even present in the ancient genomes under discussion.
In fact, that those alleles with the largest individual effects are not found in these ancient people, yet are nearly fixed in the modern populations with the most ancestry from them, supports the notion that there was actually little selection for light skin color in the populations leading to these people. If they were already 70% as lightened as current northern Europeans, it is hard to imagine the cause of such an intense selective sweep. If these additional loci can not even be slightly detected (individually) in studies using ~1000 African/European admixed individuals with nearly a million SNPs, then selection on the phenotype must be very difficult.
Suppose 10 additional loci could collectively provide 70% of the variance, yet their changes are imperceptible individually and not highly linked. Selection for them must be through a different mechanism than observable skin color.
Another option is just a lack of selection for dark skin. This could allow hundreds of different mutations to slowly accumulate in the population; any 10 of these more rare variants in combination giving lighter skin. But in that case, by simple statistics, we would certainly find many admixed individuals today with all of the African variants of 'known pigmentation alleles' but with light skin. These people do not show up in the studies.
You should be able to compare this situation with other highly heritable traits such as height. Several association studies using SNPs failed to find highly significant associations with height. Later studies with higher resolution showed that ~45% of variability could be associated with SNPs. With whole genome sequencing, the significance will surely increase as the actual alleles causing the differences are discovered.
The major difference here is that you do not have large numbers of 'pure' super tall populations mixing with unrelated 'pure' super short populations. The alleles are likely very ancient, and the linkage between even nearby SNPs has been broken down. So, unless you hit upon the actual SNP causing the phenotypic change, you see no significance in GWAS.
Also, perhaps there are examples I am unaware of, but I have yet to see a single African/European admixed individual with all the known African pigmentation alleles, but with highly freckled skin. That might be interesting.
So. I think there is no reasonable reason to believe that the early European hunter gatherers had light skin. This is similar to some kind of argument saying that the world appeared yesterday, but filled with all sorts of fake signs of the past in our brains and physical surroundings. There is no way to prove that isn't the case, but that isn't science.
Perhaps you should start a church of skin pigmentation and say that skin color is based upon your faith in the church. Maybe that's true.
Can you please tell me the study you keep mentioning about European/African populations and pigmentation. I am willing to belive they were dark skinned but for many reasons I see it as impossible for Mesolithic Europeans to be dark skinned and have a high amount of blue eyes.
ReplyDeleteI am getting very pissed that no one seems to listen. The only one of those three (near eastern!!!)mutations most associated with European light skin are more popular in Europe than the near east. Why are near easterns so brown skinned if these mutations cause pale skin in Europeans? Obviously there are other reasons why Europeans have such light skin(especially the most Mesolithic descended ones). Those mutations definitely don't explain the even lighter skin in northern Europe.
Today in Europe hair color is directly associated with eye color. If you have light blonde hair there is an under 5% chance you will have brown eyes. Who had light eyes the farmers or hunters? Modern day Sardinians are the most Neolithic descended people in Europe and happen to also be the darkest haired and eyed Europeans.
Why is the distribution of Mesolithic ancestry so similar to the distribution of light hair-skin-eyes? Why is light skin's distribution so connected with the distribution of light hair-eyes? How do you explain these things? You cant.
Tell me how a people 8,000 years ago who had olive skin, over 90% brown eyes-dark hair mixing with a dark skinned, dark haired, blue eyes people can have descendants just a few thousand years later with snow white skin, majority blonde hair, and vast majority light eyes? Do you see how crazy that sounds?
I am sick of giving you stubborn people the same old argument. You are inlove with those three mutations. You ignore all the evidence in modern people of why dark skin in Mesolithic Europe makes no sense.
I would bet you my life that genomes from Mesolithic east Europe will have plenty of people with light hair and if a redhead is found it will be prove they had light skin.
Modern correlations are just that, correlations in modern people. In 5000 years it will probably be difficult for most people to believe that eye color was ever strongly correlated with skin or hair color. Things change.
ReplyDelete" 'Beleza et al 2013 (skin color genetics in Cape Verde) leaves substantial unexplained variance. And East Asian skin color is unexplained.
ReplyDeleteIt's not necessary for any difference to have "disappeared", but the alleles we know about may explain less than we think.'
Exactly for this reason I think Loschbour and La Brana-1 should be classified with unknown skin color. "
Beleza et al 2013 is an excellent paper analyzing the genetics of pigmentation in an admixed African/European population.
However, this study has several weaknesses, which arise for various reasons. Because of these weaknesses, the authors are very careful about the language they use, and about their conclusions.
Firstly, this is an association study using SNPs. This means that the genome was only sampled every 1000 basepairs on average. If the SNPs tested are not actually 100% correlated with the causitive allele, than the signal is weakened.
Secondly, this is a study using real people, with non-random ancestry proportions relative to each SNP. If this was a study on mice, then they would have selectively bred each suspected allele into the same reference strain for the analysis of pigmentation. With people, there is no way to do this. So all pigmentation alleles are initially linked to large blocks of other ancestry related SNPs. With large numbers, the relevant SNPs can be narrowed down (due to recombination events in different individuals) but the linked ancestry may take thousands of years to be broken up in each individual case. This accounts for most of the association of ancestry with pigmentation. The authors clearly note that at least half of the signal from 'generic ancestry' can be attributed to linkage to only the four genes with the most major impact. And as I mentioned, they were VERY careful in their wording. It would not be unreasonable to suggest that 90% of the ancestry component is from this.
Thirdly, pigmentation is strongly effected by the environment. As an example, I still have a noticeable light band around my wrist from a watch I haven't worn in 15 years. When I was a beach lifeguard as a teenager, I worked with an identical twin. She was quite dark, while her sister who worked at a bank was much paler. Tanning effects are impossible to control for in association studies, and that weakens the significance of results.
I could continue with this, but I don't have the time right now. I think it would be much more reasonable for any skeptics of the genetics of pigmentation to sit down and read some scientific reviews. And if you do not understand the shortcomings of any particular analysis, look it up or ask someone.
Sure, science is never 100%. And if evidence exists to the contrary, then I'm right with you. But choosing to ignore evidence because it just 'seems wrong' to you is a sign of delusion.
"Ethiopian manuscript paintings (source: A. Davey). Ethiopians have a self-image that is lighter-skinned than their actual selves"
ReplyDeleteDo you use Byzantine and Orthodox art to show that the people in Eastern Europe can "have a self-image that is darker-skinned than their actual selves" as well?
What byzantine and orthodox art are you referring to?
ReplyDelete
ReplyDeleteSherlock Holmes - "there is no such thing as a perfect crime"
theories abound - but can we look at the past through modern humans (genetics) - and all the data from multiple scientific disciplines. - You are
Imagine trying to view all the data without bias - .
http://realhistoryww.com/world_history/ancient/Dobruja_Thrace_1.htm
is albinism a better explanation than diet
additional explanations
did the change in earths axis impact skin
http://www.space.com/10527-earth-orbit-shaped-sahara.html
http://www.stevenmtaylor.com/essays/reclaiming-human-freedom-the-denial-of-autonomy/
the adaptability of all humans is remarkable,but civilization did not flow from the north down - artifacts(known) along the time line explain all... interesting
can excessive radiation from space be responsible for the genetic mutation in the
genes responsible for skin depigmentation
http://science.nasa.gov/science-news/science-at-nasa/2009/
mutation, albinism and radioactivity is this a missing piece to the puzzle
http://www.ncbi.nlm.nih.gov/pubmed/23850808