Tătăroaice – Petre Iorgulescu-Yor (source). Today,
the steppes north of the Black Sea lie within the European world—politically,
culturally, and demographically. Not so long ago, they were home to nomads of
Central Asian origin.
A new study shows that Europeans underwent strong
selection for white skin, non-brown eyes, and non-black hair … during historic
times!
Here we present direct estimates of selection acting on functional alleles in three key genes known to be involved in human pigmentation pathways—HERC2, SLC45A2, and TYR—using allele frequency estimates from Eneolithic, Bronze Age, and modern Eastern European samples and forward simulations. Neutrality was overwhelmingly rejected for all alleles studied, with point estimates of selection ranging from around 2-10% per generation. Our results provide direct evidence that strong selection favoring lighter skin, hair, and eye pigmentation has been operating in European populations over the last 5,000 y. (Wilde et al., 2014)
If true, this finding would contradict other recent findings. Two studies have found a much earlier time frame for the whitening of European skin: 11,000 to 19,000 years ago (Beleza et al., 2013) and 7,600 to 19,200 years ago (Canfield et al., 2014). Two studies of ancient DNA indicate that non-brown eyes were already in existence 7,000 years ago in Spain (Olalde et al., 2014) and 8,000 years ago in Luxembourg (Lazaridis et al., 2013). Moreover, the genes responsible are the same as the ones in above quote.
So who is right and who is wrong? All of these
studies are probably right, but only for some early Europeans and not for all.
In the latest study, the samples come from a very small part of Europe—the
steppes north of the Black Sea:2
Ancient DNA was retrieved from 63 out of 150 Eneolithic (ca. 6,500-5,000 y ago) and Bronze Age (ca. 5,000-4,000 y ago) samples from the Pontic-Caspian steppe, mainly from modern-day Ukraine. […] We also genotyped the three pigmentation-associated SNPs in a sample of 60 modern Ukrainians (28) and observed an increase in frequency of all derived alleles between the ancient and modern samples from the same geographic region (Table 1 and Fig. S1). This implies that the pigmentation of the prehistoric population is likely to have differed from that of modern humans living in the same area.
[…] Inferring natural selection based on temporal differences in allele frequency requires the assumption of population continuity. To this end we compared the 60 mtDNA HVR1 sequences obtained from our ancient sample to 246 homologous modern sequences (29–31) from the same geographic region and found low genetic differentiation (FST = 0.00551; P = 0.0663) (32). Coalescent simulations based on the mtDNA data, accommodating uncertainty in the ancient sample age, failed to reject population continuity under a wide range of assumed ancestral population size combinations. (Wilde et al., 2014)
The authors are placing the burden of proof on the wrong null hypothesis when they state that their simulations “failed to reject population continuity.” The null hypothesis should be population discontinuity. For example, Swedes and Greeks differ in skin tone and eye color, and if we compare their autosomal DNA we get a comparable FST of 0.0084 (Genetic History of Europe, 2014). Admittedly, FST is different with mitochondrial DNA.
I suspect the authors ruled out population
discontinuity because their FST
seemed incompatible with a non-European population giving way to a European one.
If so, they forgot one thing. They were comparing a population of the present
with one that existed some 5,000 years ago. If you go farther and farther back
in time, any human population will look more and more ancestral to a
present-day population. This is especially so in northern Eurasia, where a
population ancestral to both Europeans and Amerindians existed some 20,000
years ago. Yes, the FST
does seem incompatible with a non-European population giving way to a European
one, but this is because the ancient DNA comes from a non-European population
that was closer to the time of common origin for all northern Eurasians.
This ancient DNA may come from a mixed
European/Central Asian population or an intermediate and now extinct population, perhaps similar
to the Lapps. If we look at the derived (European) alleles for the three genes
in question (HERC2, SLC45A2, TYR), the frequencies fall halfway between those of Europeans and
Asians (see Table 1 in the paper). In any case, this population does not have to be of non-European origin to be noticeably darker in skin color. As shown by the recent Mesolithic findings from Luxembourg and Spain, there used to be apparently native dark-skinned populations in the heart of Europe.
Historical background
The hypothesis of population discontinuity becomes
even more plausible if we look at the history of this region. Today, the
steppes north of the Black Sea lie within the European world—politically,
culturally, and demographically. Not so long ago, they were home to nomads of
Central Asian origin. The latest of them, the Tatars, held sway until the 18th
century.
The Tatars intermixed extensively with Slavic wives
and concubines, so much so that they now look almost as fair as other
Europeans. But they were originally quite swarthy, as attested by medieval
sources. In a 14th-century romance, The
King of Tars, a Tatar Khan converts to Christianity and turns white in the
baptismal water. Two other chronicles of the same period describe how a Tatar
Khan's Christian concubine bears him a son white on one side and black on the
other. When baptized, the child emerges from the water white on both sides
(Hornstein, 1941; Metlitzki, 1977, p. 137).
Medieval writers often noticed this difference in
skin color. Genoese notaries usually described Tatar slaves as olive-skinned
(Plazolles Guillen, 2012, p. 119). Florentine acts of sale give the following
numerical breakdown of Tatar slaves by skin color: black 2, brown 18, olive
161, fair 11, reddish 5, white 45 (Epstein, 2001, p. 108). During a trial, a
slave tried to regain her freedom by claiming to be Russian and, hence,
Christian. Her owner rebuked her, saying: “You’ve lied to me. You look more
like a Tatar, not at all like a Russian” (Plazolles Guillen, 2012, p. 119).
The Tatars were preceded by other nomads of Central
Asian origin. The Scythians (8th to 2nd century BC) were likewise described as
dark-skinned. Hippocrates wrote: “The Scythian race are tawny from the cold,
and not from the intense heat of the sun, for the whiteness of the skin is
parched by the cold, and becomes tawny” (Hippocrates).
One can find references to the contrary (Scythians, 2014). Keep in mind that the word “Scythian” was often used in the ancient
world to encompass all northern peoples:
To the ancient Greeks the Scythians, Sarmatians, Germans, and Goths were the remote northern races of antiquity. Geographically near to one another, they were often grouped together under the term “Scythians,” which by the third century B.C.E. no longer had an ethnic or national connotation and had come to designate the peoples of the remote north. (Goldenberg, 2003, p. 43)
The term “Scythian” may also have subsumed different peoples north of the Black Sea, some of whom came from Central Asia and others from areas farther north and west.
Conclusion
Because this region is on the periphery of the
European world and has been exposed to migrations from Central Asia, population
change is a likelier explanation for the findings of Wilde et al.
These findings are nonetheless interesting. Together
with the ancient DNA from Mesolithic hunter-gathers in Spain and Luxembourg, we
have further proof that many early Europeans were brown-skinned. Indeed, this
seems to have been the physical appearance of all Europeans during their first 20,000
years in Europe. Only later, within the time frame of 20,000 to 10,000 years
ago, did some of them become white.
This may seem surprising to those who believe that
white skin is an adaptation to weak sunlight at high latitudes. It was thought
that Europeans became white because their ancestors no longer needed dark pigmentation
to protect themselves against sunburn and skin cancer. Meanwhile, light
pigmentation became necessary to maintain synthesis of vitamin D. There was
admittedly the example of dark-skinned peoples who have long lived at similar
latitudes in Asia and North America, but that counterfactual was attributed to the
availability of vitamin D from a marine diet, such as among the Inuit of
northern Canada.
Wilkes et al. do, in fact, address the apparent
contradiction between their findings and the hypothesis that ancestral
Europeans became white to maintain adequate production of vitamin D in their
skin. In their Discussion section, they suggest that the shift from hunting and
gathering to farming led to a decrease in dietary vitamin D (from fatty
fish and animal liver). The main problem with this explanation is that farming
came late to many parts of Europe: about 2,000 to 3,000 years ago for East Baltic
peoples and less than 3,000 years ago for Finnish peoples (and
incompletely at that). This leaves a very narrow time frame for evolution from
brown skin to white skin. Ultimately, this question will be resolved with
retrieval of ancient DNA from these populations.
Notes
1. Although Wilde et al. mention hair color, they
did not study the main hair-color gene, MC1R.
2. Razib Khan has a great map of the ancient DNA
samples.
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
Epstein, S.A. (2001). Speaking of Slavery. Color, Ethnicity, & Human Bondage in Italy,
Ithaca: Cornell University Press.
Genetic History of Europe. (2014). Wikipedia
http://en.wikipedia.org/wiki/Genetic_history_of_Europe
Goldenberg, D.M. (2003). The Curse of Ham. Race and Slavery in early Judaism, Christianity, and
Islam, Princeton: Princeton University Press.
Hippocates. On
Airs, Waters, and Places, part 20. Translated by Francis Adams
http://classics.mit.edu/Hippocrates/airwatpl.20.20.html
Hornstein, L.H.
(1941). New analogues to the King of Tars, Modern Language Review, 36,
433-442.
Khan, R. (2014). Descent and selection is a bugger:
Black Kurgans, March 12, The Unz Review:
An Alternative Media Selection
http://www.unz.com/gnxp/descent-and-selection-is-a-bugger/
Lazaridis, I., Patterson, N., Mittnik, A., Renaud,
G., Mallick, S., et al. (2013). Ancient human genomes suggest three ancestral
populations for present-day Europeans, BioRxiv,
December 23.
http://biorxiv.org/content/early/2013/12/23/001552.full-text.pdf+html
Metlitzki, D. (1977). The Matter of Araby in Medieval England, New Haven and London, Yale
University Press.
Olalde, I., M.E. Allentoft, F. Sanchez-Quinto, G.
Saintpere, C.W.K. Chiang, et al. (2014).
Derived immune and ancestral pigmentation alleles in a 7,000-year-old
Mesolithic European, Nature, early
view
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature12960.html
Plazolles Guillen, F. (2012). “Negre e de terra de
negres infels …”: Servitude de la couleur (Valence, 1479-1516), in R. Botte and
A. Stella (eds.) Couleurs de l’esclavage
sur les deux rives de la Méditerranée (Moyen Âge – xxe siècle),
pp. 113-158, Paris: Karthala.
Scythians. (2014). Wikipedia
http://en.wikipedia.org/wiki/Scythians
Wilde, S., A. Timpson, K. Kirsanow, E. Kaiser, M.
Kayser, M. Unterländer, N. Hollfelder, I.D. Potekhina, W. Schier, M.G. Thomas,
and J. Burger. (2014). Direct evidence for positive selection of skin, hair,
and eye pigmentation in Europeans during the last 5,000 y, Proceedings of the National Academy of Sciences, published ahead of
print.
http://www.pnas.org/content/early/2014/03/05/1316513111.full.pdf+html 
24 comments:
Dr. Frost, central asians aren't some ancient wellspring from which all eurasian populations sprang, so it is erroneous to assume they had ancestral variants of skin color, eye color etc.
In fact central asians are some of the most highly admixed groups on planet earth, comparable only to latin america. The tatars themselves were mixes of european, south asian, and east asian populations. It was before in the beginning of the 000's that many researchers like Spencer Wells were looking at DNA from living central asians and concluding that europeans, east asians, south asians and other eurasians are descended from them, having gone separate ways. In fact, now we now that exactly the opposite happened.
More pertinent to the issue at hand in your post: During the eneolithic and bronze age (5000 - 4000 BC) central asia was populated very sparsely. The group that was being studied in this paper could not have been central asian because central asians didn't even exist yet. It is only later that migrations brought wheat farmers from the middle-east, pastoralists speaking indo-european from europe (of which the Tatlamakan desert dwellers were the earliest attested descendants), and finally and most gruesomely turkic-mongol warriors from east asia, who bequethed their languages to the people of turkey and central asia.
We are talking about a period before these migrations happened. When eurasian populations, still unadmixed, were living far away from each other.
These findings may be of some value in resolving the question of Indo-European language origin. There has long been a competing school of thought that traces the earliest branches of IE (sometimes called "Indo-Hittite") back to the Neolithic agricultural population of Anatolia. The population sampled in this study may well have derived from these Asia Minor agriculturalists, who were still in the process of acquiring the fairer phenotype that later came to be associated with the Indo-Europeans who adopted pastoral nomadism and spread across much of Central Asia during the Bronze and Iron Ages.
The combination of sparse populations and successive violent conquests that defined the history of the steppe region would have created more opportunities than usual for the rapid radiation of genes affecting physically obvious traits like pigmentation. The fair traits apparently so common among the Tocharians in Xinjiang and their kinsmen in the Altai region probably arose as quickly as they were swamped by the later Turkic-Mongolian-Tungus migrations.
Just for clarification, exactly how dark does this study suggest these early Kurgan people were? Are we talking about something as exotic as the Mesolithic European hunter-gatherers that caused such a stir earlier this year? Or simply olive-tan like the modern Near Easterners?
Exactly! Light pigmentation was already present long before in LBK Central Europe and blue eyes in Mesolithic Western Europe, so comparing Wilde et al. (2014)'s 'Skeletal material from 150 Eneolithic and Bronze Age individuals from the west and north Pontic region', and Bouakaze et al.(2009)'s '25 archeological human remains from southern central Siberia dating from the Bronze and Iron Ages' that 'most probably had typical European pigment features, i.e., blue or green eye color, light hair color and skin type, and were likely of European individual ancestry', we may conclude that their purported Indo-European continuity isn't at all that obvious! Instead, the selective sweep identified in the Pontic area must have been induced by immigrants from areas where those mutations were already present at saturation level, ie. in the west, what of course again severely compromises the Kurganist house of cards of a Pontic Indo European expansion.
"Only later, within the time frame of 20,000 to 10,000 years ago, did some of them become white."
Europeans have a V shaped dental arch, and a narrow face. The first known case of impacted wisdom teeth was 13,000 to 11,000 BCE in southwestern France. So obviously two separate selection pressures on something other than appearance resulted in alterations in appearance as a side effect. The convergence of the side effects on changes in appearance proves it.
These Kurgans do not show a close relationship to early European farmers in terms of mtDNA. They're most similar to early Bronze Age Central Europeans (Unetice Culture), but also not that far from modern Central Europeans.
http://polishgenes.blogspot.com.au/2014/03/pca-of-ancient-european-mtdna.html
In any case, I don't think this population had a single origin. I bet many of the females had local east Balkan and southern steppe origins, but the others, as well as the males, came from somewhere further north or east, and were more similar to the Andronovo Kurgans who were almost fixed for R1a.
Good for you, Peter!
Just one comment - you noted that "The authors are placing the burden of proof on the wrong null hypothesis when they state that their simulations 'failed to reject population continuity.' The null hypothesis should be population discontinuity."
Really, it's only because we are so habitually frequentist in our statistical reasoning that we assume there needs to be a null hypothesis to begin with. The fact that people can argue about which hypothesis should be null, and therefore what the results are, belies the claim that frequentism is "objective." The fairest way to examine the situation would be with Bayesian methodology, but using an uninformative prior. Then it would be easy to see how well each side fit the data rather than trying to give primacy to either side.
What we really need now are complete genomes from across time and space of the Kurgan cultural horizon, and especially from the early sites near the middle Volga, like Khvalynsk.
http://news.bbc.co.uk/1/hi/health/8570542.stm
rickets
well written & well thought out - i apologize if i'm misreading this, but 2009 research & your 2014 link list .0084 as the Fst/distance between Greeks & Swedes (NB: for comparison, they list .0057 between Greeks & Palestinians) http://en.wikipedia.org/wiki/Fixation_index
I'm new to this & assume that the Fst stat varies between who & what SNPs are sampled, but that it's a good "ballpark" distance indicator! is there any adjustment when comparing samples across time? & can a more Bayesian approach be used (setting the null at what we expect, etc.)
The FSTs are based on the mtdna panels. Comparing FSTs from different sets of genes is not useful.
@ anonymous: thanks for the FST info - much appreciated.
Spageti,
Yes, Central Asians are highly admixed. That's why they would be a plausible candidate for a population whose pigmentary characteristics are halfway between those of Europeans and those of East Asians.
"Central Asians didn't exist yet". Sorry, but you're wrong.
Anon,
Probably as dark as Razib Khan, although the only way to know for sure would be to revive this ancient DNA (as in Jurassic Park).
Rokus, Anon, and Davidski,
I've always been skeptical about the Kurgan theory of Indo-European origins. In any case, I don't believe that the original Indo-Europeans were the source of European white skin.
Anon,
I agree. Given the quality of the data, we can argue only the relative merits of these two models: fast evolution or population replacement. At this time, it's impossible to rule out either one.
Panjoomby and Anon,
Yes, ideally, we need Fst's for the mtDNA sequences in question. In general, Fst's are higher with mtDNA because of the higher mutation rate. So the Fst's found by Wilkes et al. should be consistent with replacement of a Central Asian population by a Slavic European population.
The Kurgan mtDNA is closer to Central European mtDNA, both modern and Bronze Age, then Central Asian mtDNA, both modern and Bronze Age. See here...
http://i129.photobucket.com/albums/p217/dpwes/Wilde_Brandt_mtDNA2.png~original
http://i129.photobucket.com/albums/p217/dpwes/Wilde_Brandt_mtDNA_PCA2.png~original
So there's very little doubt that these Kurgan groups contributed to the modern European mtDNA gene pool, along with groups from the Atlantic fringe, like the Bell Beakers, and the remnants of early Neolithic farmers across Europe.
Out of these three, the Kurgans had to be the Indo-European speakers, while the others contributed non-Indo-European substrata, like farmer loan words, to modern European languages.
The only question here is whether the Kurgan groups tested by Wilde et al. were homogenous, and became lighter over time due to positive selection and mixing with the other Europeans, or whether they were a mix of more northerly and lighter Proto-Indo-Europeans and brunet farmers from the east Balkans and southern steppe.
The fact that the Middle Bronze Age Andronovo Kurgan groups of South Siberia were already very fair and had higher frequencies of blond hair and blue/green eyes than most modern Europeans, supports the latter scenario. So in other words, the Proto-Indo-Europeans might have come from some ancient Hyperborea north of the steppe, and were much lighter than the people they dominated to the south, who then joined them in the expansion deeper into Europe.
Needles to say, the Proto-Indo-European expansion was very likely a male driven phenomenon. So the fact that the Andronovo and related groups carried extreme frequencies of R1a, coupled with the fact that ANE proxy Mal'ta boy also belonged to R, and ANE seems to have entered most of Europe after the Neolithic, basically means that what we're looking at here is a Y-DNA R/ANE/Indo-European invasion of Europe during the Copper Age, which first started with a drive into Ukraine and the east Balkans, where a lot of brunet farmer females lived. Kind of like this...
http://upload.wikimedia.org/wikipedia/commons/2/20/Kurgan_map.png
Characteristics of hair skin and eyes, which came from sexual selection of women and are related to oestrogenisation, may have been differentially selected once the steppe tunda period ended. The Spain and Luxembourg studies both finding a blue eyes and dark skin combination is very hard to explain otherwise
The hair skin and eyes traits spread outside the steppe tunda area, but white skin was maybe selected against for a time because there was more male-male competition and white skin went along with oestrogenisation. The gorilla-like Luxembourg man shows traits of robustness
I think maybe white skin going with oestrogenisation somehow is the explanation.
Anon,
Probably as dark as Razib Khan, although the only way to know for sure would be to revive this ancient DNA (as in Jurassic Park).
The frequencies for these genes basically match modern Levantine populations, Syrians and Palestinians.
The genes in question are
- the European variant at SLC45A2, what gives much of the skin pigment difference between Europeans and non-European Middle Easterners,
- a couple of genes one of which affects eye pigment mainly and the other which has very low impact on skin pigment (and have a more questionable selective relationship to skin pigment).
So from this data, probably more dark as Salma Hayek (if she lived in relatively cloudy Ukraine her whole life) than dark as Razib Khan (or any Bengalis).
Brown skinned people with blue eyes are not so common even in mixed race people. You would look twice if you saw such a person. I don't think there have been so many old bones looked at for the blue eyes and brown skin combination to be popping up twice; but it has. So at this point it seems to me the selection for white skin did not go along with selection for blue eyes for thousands of years. I'm confident the selection for blonde hair and blue eyes is sexual.
Years ago Peter mentioned the possibility white skin prevented spousal abuse in monogamous living, and also inhibited sexual arousal to a certain extent. One can't help noticing that tanned skin is the look for young women, but wasn't in a previous era. So we have the evidence before us of how blue eyes could have been selected for, while white skin selected against in women.
"The gorilla-like Luxembourg man shows traits of robustness"
Like Cro-magnon skeletons, very solid bones, no sign of rickets.
http://upload.wikimedia.org/wikipedia/commons/a/a9/XrayRicketsLegssmall.jpg
http://en.wikipedia.org/wiki/Rickets
"Vitamin D insufficiency was found in 40% of non-Western immigrants in the Netherlands, and in more than 80% of Turkish and Moroccan immigrants."
Davidski,
We need a comparison between Kurgan mtDNA and Scythian mtDNA (I'm not convinced that Kazakhstan is an adequate proxy). Again, a population can be brown-skinned without being genetically distant. We see this with the Mesolithic samples from Spain and Luxembourg.
Sean,
Minor correction: the Spanish and Luxembourg individuals had non-brown eyes. We don't know whether they were blue-eyed. My explanation is that whitening of skin color began after eye color began to diversify. These two individuals would thus be descended from a demographic expansion out of northern Europe that took place at an earlier time, i.e. at an early phase of the period of intense sexual selection.
Anon,
The authors say nothing about SLC24A5, which is the third gene involved in the whitening of European skin. So it would be difficult to say how dark the Kurgans were.
Anon,
Vitamin D levels are normally low in Middle Eastern populations, even when they live there and are regularly exposed to the sun. Different human populations have different vitamin D metabolisms.
The authors say nothing about SLC24A5, which is the third gene involved in the whitening of European skin. So it would be difficult to say how dark the Kurgans were.
Sure, my point is that the frequencies of the genes we do know about are more like Lebanon than Bengal.
The West Eurasian variant of SLC24A5 (high frequencies in Middle East plus Europe and quite high frequencies outside Europe) is already known as present in Oetzi, so its odds of being present within this Kurgan population at high frequency is fairly good.
SLC24A5 could have a non-West Eurasian frequency in this population though, we will have to wait and see.
"Vitamin D levels are..."
The reason I wonder is Cro-magnon (and Neanderthals) are described as particularly robust which I assume implies particularly sturdy bones?
A different course of inquiry could be this:
oestrogenisation made women more caring for the children in Europe and allowed/forced an increased paternal investment on offspring.
Do oestrogenisation make women more caring for children and cuckolding less frequent?
Because, if she cuckolds her male provider, she should do it with another male provider and, in ancient time, the previous children would be in a dangerous situation (or at least very disadvantaged).
Maybe it is a chance, but fairy tales talk about the fairy princess menaced by their darker haired/skinned sisters.
First of all Peter, most of Europe left pre history around 2,000 or less years ago. The oldest ancient writings i know of describing the physical features of north-west Europeans(i.e. Celts and Germans) describe them as stero typical tall, light haired, light eyed, and snow white skinned. All writtings i know of comparing skin color of Europeans to west asians or north Africans always say the European group(whether Romans, Iberians, Iyrllians) is lighter. By the time Europe left pre history the genetic makeup was almost no differnt in every region as today, you already had most of the major modern ethnic groups.
Your interpretation of MA-1 boy is incorrect. He was not mixed central asian-European, that's what i thought at first when i only knew about his admixture results. Actualley he is most related to Mesolithic Europeans, he was like their ancient eastern brother. He was also a pure west Eurasian, not intermediate between modern Eurasians. His population contributed ancestry to many modern populations(America, Siberia, south asia, west asia, and Europe) unlike their western brothers who only contributed ancestry to Europeans and possibly a tiny winy bit to some people in Asia and north-west Africa.
I agree with you that these bronze age proto-Indo Europeans and Eneolithic people are most likely not the main ancestors of modern east Europeans. The alleles in SNP's rs12913832, rs16891982, and rs1042602 are too differnt.
Bronze and Iron age Indo Iranians in Siberia had almost complete opposite results in rs12913832 and rs16891982 to their supposed Yamna ancestors and Catacomb relatives. They had results that would be expected of modern Europeans, so in my opinion if there was some type of crazy pigmentation change in eastern Europe in the last 5,000 years it was complete by at least 4,000 years ago.
I am still very skeptical that skin color can be accurately predicted. Those three mutations YOU STILL CALL EUROPEAN, are as popular in near easterns as they are in Europeans(except the one in rs16891982 which is ~50% in near easterns and ~100% in Europeans) so i do not think they make an unbelievable effect on skin color. I know all the experts say they do and i trust them, but i think there are other mutations that if Europeans did not have they would be as dark as near easterns.
I am tending towards saying La Brana-1 and loschbour had dark skin but i am still not sure. If for example a genome from Mesolithic Russia finds that they had light hair and eyes but none of the mutations associated with European light skin, that will be prove there are unknown light skin mutations.
It is strange that these ancient Pontiac steppe people where down in all of them, even below near eastern and early European farmer averages. I think Mesolithic ancestry could be the reason. I have heard that the forest Neolithic and early Indo Europeans had very Mesolithic like skull shapes. This is defended by over 50% Mesolithic mtDNA U5-U4-U2e in bronze-iron age Indo Iranians(light) and similar percentages in Catcacomb and Yamna cultures(dark). Maybe some hunter gatherer groups in east europe were more brown eyed than in west Europe, and maybe La Brana-1 and Loschbour are blue eyed flukes(not normal for their people).
The last thing i will say Peter is that these ancient Pontaic steppe people were modern European. They had the same mixed hunter WHG/WHG and farmer EEF ancestry modern Europeans do. No where outside of Europe do you find an mtDNA gene pool like theirs.
"The authors say nothing about SLC24A5, which is the third gene involved in the whitening of European skin. So it would be difficult to say how dark the Kurgans were."
According to you Peter west asians should be as white as Europeans. Why are you so stubborn? These mutations are not European we have PROVE at least the ones in genes SLC24A5 and TYR came to Europe with farming from the near east.
Are west asians white skinned? NO. So obviously there are unknown light skin mutations in Europe. Do you have eyes or are able to reason Peter?
'The frequencies for these genes basically match modern Levantine populations, Syrians and Palestinians.
The genes in question are
- the European variant at SLC45A2, what gives much of the skin pigment difference between Europeans and non-European Middle Easterners,
- a couple of genes one of which affects eye pigment mainly and the other which has very low impact on skin pigment (and have a more questionable selective relationship to skin pigment).
So from this data, probably more dark as Salma Hayek (if she lived in relatively cloudy Ukraine her whole life) than dark as Razib Khan (or any Bengalis)."
What the hell? Why does everyone believe these light skin mutations are exclusivity European? If those three 'European' mutations Peter is so inlove with are the main causes to European light skin, we should expect Iraqis to be at least as dark as Iberians.
Comparsion
Iraqi Google images
https://www.google.com/search?q=iraqi+people&espv=210&es_sm=122&source=lnms&tbm=isch&sa=X&ei=YAguU9XOEqiQyAGxs4GwAQ&ved=0CAkQ_AUoAQ&biw=1024&bih=667
Guide to Spanish phenotype
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CCgQFjAA&url=http%3A%2F%2Fwww.theapricity.com%2Fforum%2Fshowthread.php%3F106927-Guide-to-Spanish-phenotypes-(by-regions)&ei=kwguU5z5AoThyQGks4CwDQ&usg=AFQjCNG1X2QJwXNqh5kai5DXemYQ83lnqg&sig2=OyLg5J_3O4ip3n4ToYo5DQ&bvm=bv.62922401,d.aWc
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