Saturday, 8 February 2014

A little less brown and not necessarily blue-eyed


 
 
The skin color is about right. Not so sure about the eyes (source: Spanish National Research Council (CSIC)). There seems to have been a succession of changes to hair, eye, and skin color within a relatively restricted area of Europe. These changes then spread outward, the changes to eye color being apparently the earliest.


Ancient DNA has been retrieved from another Mesolithic hunter-gatherer, who is dated to 7,000 years ago and comes from La Braña-Arintero, Spain. We again see a strange combination of dark skin and light eyes. If we look at the three genes that produce white skin, only one of them, TYRP1, had the derived ‘European’ allele. The other two had the ancestral allele. So this Mesolithic individual was a bit lighter-skinned than the one from Luxembourg, dated to 8,000 BP, who had ancestral alleles at all three loci:
 

Of the ten variants, the Mesolithic genome carried the ancestral and non-selected allele as a homozygote in three regions: C12orf29 (a gene with unknown function), SLC45A2 (rs16891982) and SLC24A5 (rs1426654). The latter two variants are the two strongest known loci affecting light skin pigmentation in Europeans and their ancestral alleles and associated haplotypes are either absent or segregate at very low frequencies in extant Europeans (3% and 0% for SLC45A2 and SLC24A5, respectively). We subsequently examined all genes known to be associated with pigmentation in Europeans, and found ancestral alleles in MC1R, TYR and KITLG, and derived alleles in TYRP1, ASIP and IRF4. (Olalde et al., 2014)


Media reports describe the two Mesolithic individuals from Spain and Luxembourg as blue-eyed, although this is not what either study actually found. All we know is that their eyes were not brown. They had blue, gray, hazel, or green eyes:
 

[The individual had] the associated homozygous haplotype spanning the HERC2–OCA2 locus that is strongly associated with blue eye colour. Moreover, a prediction of eye colour based on genotypes at additional loci using HIrisPlex24 produced a 0.823 maximal and 0.672 minimal probability for being non-brown-eyed (Supplementary Information). The genotypic combination leading to a predicted phenotype of dark skin and non-brown eyes is unique and no longer present in contemporary European populations. Our results indicate that the adaptive spread of light skin pigmentation alleles was not complete in some European populations by the Mesolithic, and that the spread of alleles associated with light/blue eye colour may have preceded changes in skin pigmentation. (Olalde et al., 2014)


These findings seem to conflict with previous estimates of the time frame when European skin became white: 11,000 to 19,000 years ago according to Beleza et al. (2013) and 7,600 to 19,200 years ago according to Canfield et al. (2014). I would argue that this was indeed the time frame when European skin became white; however, white skin was initially confined to a geographic area that covered only part of Europe, essentially the plains of the north and east.

It also appears that the changes to hair, eye, and skin color did not happen simultaneously. First came the diversification of eye color and then the diversification of hair color. Parallel to these changes, and extending over a longer time, was the whitening of skin color. 

The most surprising—though least commented on—finding is that this Mesolithic hunter-gatherer had the ancestral allele for KITLG. According to Beleza et al. (2013), this gene was involved in the first stage of skin lightening that affected the common ancestors of Europeans and East Asians some 30,000 years ago. It looks like this first stage, like the second stage over 10,000 years later, affected Europeans only within part of Europe. The Mesolithic hunter-gatherers from Spain and Luxembourg thus seem to have belonged to a population that was peripheral to the evolution of white skin and multi-hued hair and eyes.


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 

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

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

40 comments:

barakobama said...

There is no such thing as white(light) skin genes. There are genes associated with light skin in Europeans. The three main ones are JUST AS POPULAR IN NEAR EASTERNS AS IN EUROPEANS except for the one in gene SLC45A2 which is still around 50% in near easterns.

There are other factors to creating light skin in Europe. How do you explain skin color difference between northern and southern Europeans and how do you explain skin color differences between southern Europeans and near easterns if they all have these genes?

I have heard that the light skin mutation in gene KITLG is most popular in literally black or dark brown skinned Papuans. People confuse west Eurasian with European and east Eurasian with east Asian. European is not a race it gets so annoying when people assume it is. Europeans and east Asians having common ancestors 30,000 years ago, what? Isn't MA-1 and multiple mtDNA U samples from Europe that are over 30,000 years old, and 40,000 year old mtDNA B sample in China good enough evidence to prove their common ancestors lived much longer ago?

Another bad assumption you make Peter is that these mutations can perfectly predict skin color. We don't know who was darker skinned La Brana-1 or Loschbour. You should say I think one was darker than the other.

All we know is that both la Brana-1 and Loschbour probably had black hair and light eyes. The skin color is unknown. A good guess would be dark but there is also a good chance no one has discovered the real cause for European light skin.

When someone finds a light haired Mesolithic Russian missing the so called European light skin genes, I will say I told you so.

Anonymous said...

The pic is down.

Anonymous said...

Peter - The most surprising—though least commented on—finding is that this Mesolithic hunter-gatherer had the ancestral allele for KITLG.
"barakobama" - I have heard that the light skin mutation in gene KITLG is most popular in literally black or dark brown skinned Papuans.
Yes the derived allele is also at fixture for Oceanians and almost certainly in Australian Aborigines.

See - http://openi.nlm.nih.gov/detailedresult.php?img=2685456_pgen.1000500.g004&req=4 for a figure showing the derived KITLG allele at 100%, fixture, in Papuans (as in Europeans)while slightly lower frequencies in East Asians.

A lot seems to have been made of Europeans and East Asians sharing the derived alleles... but if southern South Asians and Papuans who are essentially as dark as West Africans also share the derived allele, how much can it explain?

Papuans and Australian Aboriginal people (and other isolated "black" peoples like the Andamanese) seem like a really good check for a lot of pigmentation genetics. They participate in most of the allele sweeps that set all Eurasians apart from Africans and most of the allele sweeps that set East Asians apart from Africans (and Europeans to a lesser extent), yet have as dark skin as Africans.

I red an interesting article on pigmentation genetics this week -http://www.redorbit.com/news/science/1113066376/rock-pigeon-pigmentation-human-medical-research-020714/

"A team of American researchers has discovered mutations in three genes that determine feather color in domestic rock pigeons, according to a new study in Current Biology. The same genes direct the pigmentation of human skin – meaning the findings may have implications for medical research. ...

The study team learned that coding and regulatory distinctions in the interactions among the genes Tyrp1, Sox10 and Slc45a2 affect multiple color phenotypes, or appearances, in pigeons. In one instance, scientists learned that a “reddish” mutation in Tyrp1 arose just once and was spread all through the species by selective mating. Different forms of Tyrp1 make pigeons blue-gray, red or brown.

Variations of Sox10 make pigeons red, regardless of what form Tyrp1 takes, the researchers found. Also, Slc45a2 makes the pigeons’ colors either very strong or look washed out."


The paper can be seen here http://www.cell.com/current-biology/abstract/S0960-9822(14)00021-9#ResultsandDiscussion

In the population of pigeons, the Tyrp1 variants look to be of similar effect in lightening as the SLC45a2 variants, but biased towards reducing black rather than red pigment.

Sox10 is an interesting gene, because it isn't selected for general human pigment variation and mutations seem to result ina condition called Waardenburg Syndrome that is responsible for most blue eyed, dark skinned people that presently exist on earth.

Note - although it is hard to judge, when the very striking dark skin, light blue eyes phenotype does occur, it seems it isn't actually because of "European blue eyes" alleles combining with dark skin alleles (as we might naively suggest), just a mutation in Sox10, leading to Waardenburg Syndrome.

http://tinyurl.com/pvrszfs for some people with Waardenburg Syndrome, showing how it can result in the dark skin, light eyes combination (many show characteristic some characteristic facial dysmorphology as well, perhaps because this gene has a wide role in more processes than most of the pigment genes we know to vary in humans).

genetiker said...

You're confused Peter. The KITLG SNP for which Veddoids and their Caucasoid and Mongoloid descendants have the derived allele is rs642742. That SNP is missing in the La Braña 1 genome. It was another KITLG SNP, rs12821256, that was found to have the ancestral allele.

And you can't cordon off the northeast from the rest of Europe. For most of the Upper Paleolithic, the whole of Europe was steppe, not just the northeast.

My analyses of the La Braña 1 genome indicate that La Braña 1 was autosomally predominantly Aryan, and that the Kurgan hypothesis is therefore false.

Anonymous said...

"The Mesolithic hunter-gatherers from Spain and Luxembourg thus seem to have belonged to a population that was peripheral to the evolution of white skin and multi-hued hair and eyes."

Interesting thought.

.

@anon

very interesting.

I think some of Razib Khan's posts mentioned KITLG mostly effecting hair color but I may have misremembered it.

hair color site:scienceblogs.com/gnxp

Anonymous said...

@genetiker

"And you can't cordon off the northeast from the rest of Europe. For most of the Upper Paleolithic, the whole of Europe was steppe, not just the northeast."

Wasn't it that most of Europe was part of the mammoth steppe with a southern forest zone?

http://img571.imageshack.us/img571/6525/7dt9.png

(although the forest zone doesn't include Luxembourg the two ecozones might have had different selection pressures on phenotype i guess.)

barakobama said...

Genetiker your admixtures are interesting but why do you give labels like Aryan? What is Aryan no one really knows. The Amerdian in La Brana-1 may really be ANE ancestry and his Meditreaen farmer ancestry.

barakobama said...

Which KITLG mutation was La Brana-1 missing? How did you gene get his raw data?

genetiker said...

Mammoth steppe is a synonym for steppe-tundra. During the LGM, from 25 to 15 ka, the north was steppe-tundra and the south was forest steppe.

See this page.

It says that

"Ice sheets covered northern Europe and Scandinavia. Most of the rest of northern Europe resembled semi-desert, with a mixture of tundra and grassland elements (steppe-tundra). In southern Europe, vegetation resembled a semi-desert steppe, with scattered pockets of trees in moist areas."

For other time periods, see this page. On the maps there you'll see "dry steppe" instead of "forest steppe".

genetiker said...

I don't use PC terminology or David Reich's ridiculous neologisms.

No apologies.

Average Joe said...

My analyses of the La Braña 1 genome indicate that La Braña 1 was autosomally predominantly Aryan

How do you define "Ayran?"

Average Joe said...

Sorry, I mispelled Aryan.

genetiker said...

Aryans were the Y R1 and mt U inhabitants of Upper Paleolithic Europe.

They spoke languages ancestral to the Aryan (Indo-European) languages that we know today.

And they had their own distinctive set of religious beliefs.

barakobama said...

"Aryans were the Y R1 and mt U inhabitants of Upper Paleolithic Europe.

They spoke languages ancestral to the Aryan (Indo-European) languages that we know today.

And they had their own distinctive set of religious beliefs."

That's just a hypothesis. Your generalizing mtDNA U and RO has been found in Upper Palaeolithic Europe. Y DNA I, C-V20, and F-96 were likely the main haplogroups of Mesolithic Europeans. R1a I think likely existed in far eastern Europe and central Asia(with a related MA-1 like people).

genetiker said...

Stop regurgitating Maciamo's crap and learn to think for yourself.

barakobama said...

I consider what others say and look at it myself and sometimes agree. How do you explain such a basal form of Y DNA F in Europe? People used to say that about Y DNA C-V20 and now we know it is pre-Neolithic.

genetiker said...

I never said anything about F.

Anonymous said...

The original home of Nordic man is in the Tropics:

http://i.imgur.com/PGzhdgF.jpg

Davidski said...

genetiker,

Thanks for the comedy relief, but if La Brana and Loschbour were so called Aryans, then why didn't they have the same markers for blond hair, fair skin and R1a as the Kurgan people from South Siberia?

Secondly, obviously there were no Indo-Europeans in Europe during the Neolithic, because Neolithic people didn't speak Indo-European languages, but they did leave traces of their non-Indo-European languages everywhere except the southern Russian steppe and forest steppe. See here at 28:45...

http://www.youtube.com/watch?v=vFZhWfL0ocY&list=PLAXoDomeFLX90fTHi0W8lYBtEoZHSBH2i&index=13

So the steppe theory is doing better than ever, and should be confirmed with the first Copper Age genome from Russia. La Brana was just a close Mesolithic cousin of the so called Aryans, who left very few direct descendants in Europe, unlike the so called Aryans.

barakobama said...

Anonymous Nordic man is from the tropics, what? This is a joke right? Nordic stands for Denmark, Sweden, Norway. The language formed I think the iron age it is not a distinct race.

genetiker said...

Davidski,

I never said anything about Loschbour.

You forgot to mention that the Kurgan people had blue eyes. La Braña 1 also had blue eyes, and the Y Q proto-Aryan ancestors of Amerindians carried the blue eyes allele of rs12913832 too.

You assume that blond hair and fair skin were universal traits among Aryans, and that they were universal going all the way back to 8,000 years ago. You have no grounds for such an assumption. The Mal'ta genome shows that proto-Aryans originally had none of these traits.

Your insistence that only R1a men spoke Aryan languages is a load of Slavocentric nonsense. It's as clear as can be that R1b men spoke centum languages and that R1a men spoke satem languages.

It was only the Mediterranean agriculturalists that didn't speak Aryan languages. The Aryan Nordic hunter-gatherers that were there first and whom they partially displaced did speak them. What the linguists have seen as substrates is in fact just the influence of the languages of the Mediterranean immigrants on those of the Nordic natives. The languages of the northeast show the least influence from the Mediterranean languages because the northeast was the last place to receive Mediterranean immigration, and it received the least of it. The Baltic languages, and not the Slavic languages, remain the closest to the original Aryan languages, because the Baltic areas received even less Mediterranean immigration than the Slavic areas, and received it later.

The genomes of Copper Age Russians might prove that they were R1, but they will of course not prove that Copper Age Western Europeans weren't also R1.

The Y haplotype of La Braña 1 has no bearing on his autosomal DNA, and the degree to which that DNA is shared with modern Europeans.

Davidski said...

You didn't watch the video I linked to, did you?

The Baltic region has non-Indo-European substrate influences (potentially linked to the high frequency of N1c there), and the only part of the world where they are lacking is the forest steppe of what is now Russia (where R1a peaks at over 70%).

Moreover, at the moment there's nothing tying R1b to the Kurgan cultures. It might have initially been a marker of related ANE-derived groups like the Bell Beakers, Tyrrhenian language speakers, Hurrians and/or Kura-Araxes people, before being Indo-Europeanized in Central Europe during the Bronze Age. We'll see.

And there's certainly no evidence that the hunter-gatherers of Western Europe spoke anything close to Indo-European. You just pulled that out of the proverbial, because for some odd reason you think that anyone with a high level of the "North European" component must be an Indo-European.

Unfortunately, I've got a feeling we'll be seeing a lot more champagne humor like this from you over the coming months, but not for much longer than that, because those ancient genomes from Russia are on the way.

szopeno said...

You know, on my way to work I came to idea being an addendum to the "sexual selection" theory of white skin and blue eyes appearance.

In warmer areas 12 year old child can essentially live partially on its own. 14 year old child can go and gather food.

On the other hand, in colder areas 14 year-old boy has dim chances of succeeding in hunting.

Therefore, it would seem to be advantageous for young boys to appear "young", so they a) evoke maternal/paternal feelings form olders b) do not seem like a threat to older men c) therefore, have larger chances to survive a prolonged period of dependency on others for providing food.

Does that make sense? I mean in context that paler skin and hair is often associated with children.

Lisa Evans said...

If we are just throwing out ideas, then how about pale skin and hair were selected because it allowed people to very quickly check themselves and each other for ectoparasites?

In the warmer regions, people can just leisurely check themselves any time of the day, or anytime they feel something. In northern regions, people wear lots of clothing where bugs can hide, and they have to wear those clothes all day for much of the year. Only briefly could they be removed in the coldest winter months.

The ability to see fleas and ticks quickly and in very low light (such as inside around a fire) might be extremely advantageous.

This ability would be especially useful when people began keeping domesticated animals (and opportunistic rodents) in and near their homes. The farmers and herders moving into the coldest regions would benefit most from light skin and hair for this reason. If multiple waves of deadly rat/flea/tick transmitted pathogens swept through an area, then selection would be rapid.

The hunter gatherers wouldn't have benefitted from light features as much, because they didn't store grain or live with domestic animals besides dogs. The fact that domestic animals also have strange pigmentation might be via a similar mechanism.

When the need to hide is removed, evolution favors alternative coloration. Large changes in pigmentation on a single animal (such as black and white spots on cows or goats) or variable coloration within sibling groups prevents the parasites from adapting, while allowing them to be easily seen by birds, or people.

genetiker said...

Davidski,

It would not be surprising to see influences from Uralic languages in parts of the Baltic region given the high frequencies of N there. That doesn't change the well-known fact that Baltic languages are closer to the original Aryan languages than Slavic languages. The Wikipedia article on Lithuanian states that

"The Lithuanian language is often said to be the most conservative living Indo-European language, retaining many features of Proto-Indo-European now lost in other Indo-European languages."

This page says that

"Lithuanian... is the most archaic among all the Indo-European languages spoken today, and as a result it is very useful, indeed, indispensable in the study of Indo-European linguistics."

And this page says that

"Lithuanian has been an especially important language for scholars seeking to reconstruct the Proto-Indo-European tongue because Lithuanian appears to be strikingly conservative in its grammar and its acquisition of vocabulary. The language has changed remarkably little in perhaps 7,000 years. (Some scholars point out--only half in joke--that a Lithuanian peasant can often understand simple phrases in Sanskrit.) For whatever mysterious reason, this language preserves some very old features which have disappeared from practically all the other languages of the Indo-European language family."

The fact that there's no link between R1b and the Kurgan cultures tells us nothing about what language R1b men spoke, or whether the Kurgan hypothesis is correct.

You say that there's no evidence that Western European hunter-gatherers spoke Aryan languages. What you don't seem to get is that there's no direct evidence for what language any prehistoric people spoke, anywhere on earth, and there never will be any. The languages spoken by prehistoric peoples can only be determined by inference, and inference tells us that R1b men spoke centum Aryan languages just as certainly as it tells us that R1a men spoke satem Aryan languages.

It's not the high level of the Nordic component in the globe13 analysis that indicates that La Braña 1 was predominantly Aryan, it's the high level of Indianid component in the globe4 analysis, and the high level of the Aryan Nordic component in the MDLP World-22 analysis. The high level of the Indianid component tells us that La Braña 1 had DNA in common with Amerindians, and we know that the Caucasoid admixture in Amerindians is from Y Q proto-Aryan males. The Aryan Nordic component which is modal for La Braña 1 was also modal for Mal'ta 1 and Afontova Gora 2, both of which had Aryan or proto-Aryan Y chromosomes. The map for the Aryan Nordic component shows that it goes down into India, so we know that it was carried by Aryans. And note that the Aryan Nordic component peaks in Latvians and Lithuanians, which is consistent with the unique status of the Baltic languages as being the most conservative.

You again mention the Russian genomes. You failed to comprehend that those genomes cannot disprove the presence of Aryan languages elsewhere in Europe at the same, or at earlier times.

Peter Fros_ said...

Please leave out the "Aryan" stuff. There are other blogs for that sort of thing.

Barak,

It's not clear to me why you feel it's important that the Mesolithic hunter-gatherers of Western Europe were light-skinned. As you argue yourself, they must have become light-skinned through a very different suite of genetic changes. They thus tell us nothing about the evolution of white skin among the ancestors of present-day Europeans.

Barak and others,

The light-skin KITLG allele is confined to lighter-skinned Eurasian populations. On the range map, I see populations from Iran and Afghanistan, but nothing from the Indian subcontinent. There are also two points from PNG and Melanesia. The last two cases seem unusual, although there is considerable skin color variability in both régions. Yes, there are relatively light-skinned Papuans. I don't think this information invalidates the role of this derived allele in lightening skin color.

Genetiker,

I'm confused by your comment. Are you saying that the La Brana individual had the derived light-skin allele at KITLG? My reading of the paper is that it had the ancestral allele, i.e., for dark skin.

By definition, "steppe-tundra" exists only on open plains. It's not just a matter of vegetation. It's also topography. For most of the last ice age, the South and West of Europe had a mixture of park tundra and boreal forest.

Nor am I saying that the humans on the steppe-tundra were cordoned off from humans elsewhere in Europe. There was probably a succession of demic expansions out of that region and into the rest of Europe, as well as into the Middle East.

Since I am held responsible for the comments on my blog, and since I don't use a pseudonym, I reserve the right to delete comments that use offensive terminology.

barakobama said...

Peter what I have been saying is there are some UNKNOWN causes to Europeans have light skin and La Brana-1 and Loschbour had them. I have given you prove more than a gazillion times that these mutations are near eastern not European. You and others center these mutations around Europeans and ignore their equal presence in near easterns(SLC45A2-).

To me La Brana-1 and Loschbour's skin color is unknown. Because I don't believe every mutation that causes light skin in Europe has been discovered. I see it as more likely they had dark skin, but I have no idea what shade it would be. I would guess it was a deep shade of brown like in south Asians and native Americans. There are so many possibilities though and that is why I think it is unknown what skin color they had and don't like to make assumptions which could be incorrect. I really dis agree with this thread which says a little less brown, I think you assume the science of skin color is totally figured out. I am sure the few Europeans without the near eastern mutation in gene SLC24A5 are not any darker skinned than other people in their population.

I have listed the reasons many times why dark skin in Mesolithic (west)Europeans is not constant with many statics in modern people.

I think the way to come closest to figuring out the pigmentation history of Europe and how La brana-1, Loschbour, and Stuttgart are connected is to take all the info you can from those old anthropologist from the 1800's and early 1900's. Also serious modern studies on pigmentation and the genes would be even better. I have noticed that dark skin is not very uncommon in north-west Europeans and many can tan very well. I can name quite a few who were born literally with brown skin(most though have dark brown eyes). I wonder if they are missing some of the near eastern light skin mutations which could have become dominate through natural selection. Maybe there are many random brown skinned people in north Europe because of the higher amount of Mesolithic ancestry. But what is strange is that there are probably more brown skinned people in south Europe.

We must be talking about a different KITLG mutations because the maps I saw showed they are 100% in Papuans. You should not assume that ever gene connected with skin color has been discovered.

barakobama said...

"Peter what I have been saying is there are some UNKNOWN causes to Europeans have light skin and La Brana-1 and Loschbour had them."

I meant may have had them.

Anonymous said...

Alright, I just looked back over everything barakobama has been saying. So, now I am pretty convinced. You can't really argue with that kind of proof.

There are some unknown causes to Europeans having light skin and La Brana-1 and Loschbour had them. Most northern europeans today also have them. This is why the extremely rare northern europeans without the near eastern SLC24A5 allele are not any darker than those having it. The fact that these people have never been seen is of no consequence. Lack of evidence is not evidence of lacking.

Light eyes and light skin and light hair go together. Modern people with light eyes also have the lightest skin and lightest hair. This fact is clearly undeniable evidence that the first people with light eyes also had light skin. Haven't you seen the statistics on this? They even go back to the 18 and 1900s, and come from places like Germany.

Heck, northeast asians have light skin too, and they don't even have the light eyes and hair yet. So clearly the skin comes first, then the hair and eyes. So if early european hunter gatherers had light eyes, then it is clear that they also had the difficult to detect alleles for light skin.

When the farmers moved in, they brought their own middle eastern light skin genes, but they just coincidentally drifted to 100% frequency. They have virtually no effect on skin coloration in people already carrying the mesolithic european skin lightening genes.

The fact that these genes haven't been discovered yet is just more proof that they exist. How else can you explain the fact that La Brana-1 and Loschbour might have probably had them?

Wake up people! Do you not even read the previous posts?! Facts are facts and proof is proof! We don't have a time machine, so how could anyone really know?! Please argue with me!

Gottlieb said...

Do not stop to think whether European rivers of Central Europe were major vectors of population dispersion across the continent as well as by mutations?
Luxembourg appears to be close to the Rhine as far as I know.
Another hypothesis could be the spread of genes by atlantica and Baltic coast , which together result in , almost pinkish , very clear Celtic fair skin that is present from the north of Portugal ( in more moderate levels ) to Estonia . These Celtic sea genes can be , at least , the phenotype '' '' northern European origin of light skin . If the distribution of light-skinned Celtic took the west - European coasts ( France, the Netherlands , northern Spain ) , why not through England itself ? England was connected to the mainland at that time . This type of skin , typically European , might have initially originated in northern Spain and spread throughout Western Europe and the Baltic coast .
Or , selection of mutations that result in clear skin , occur in parallel in different regions of the continent or elsewhere . I have the impression that the Slavs are more able to bake your skin to the sun than the British .
Evolutionary psychology and psychogenetic seem from many very elaborate hypotheses to explain what seems to me not to be too complex to understand . People started to select the clear skin among other attractions, specifically because they were beautiful (they are cute ) . Sexual attraction . Especially it. Relates to neoteny I do not know as well , but even the most manly man , falls in love when you see a puppy or a baby .
We are externalizing a series of complex assumptions that are based on logical selection patterns . However , we forget that human beings are quintessentially illogical.
Of course , our brain understands that the most beautiful people tend to be more healthy, intelligent ( not enough already be pretty) and good in bed. What is not necessarily true. We are animals and animals are anthropomorphically illogical beings .
In the past , the human being was extremely shortsighted , like other animals , the selection process is to give immediate survival because there was no medicine, modern life etc. .

Ben10 said...

Neoteny means that other characters, beside those immediately visible, may display youthful characteristics.
It would be interesting to discuss the following points for white skin/neotenic versus dark/non-neotenic, in a postglacial cool climate situation.

1) vitamin D availability from a white skin mother to her developing fetus.
2)How long can they each breast feed. One of my uncle (blond blue eyed) was breast fed until he was ten.
3)Age of first menarche, menopause, Andropause and general longevity of the types.
4)If the cerebral development of the neotenic fetus/infant is prolonged, that means profound differences in cognitive features vs non-neotenic.
5)Also, the retina is basically a outgrowth of the brain while the melanocytes and part of the facial bone structure are produced from neural crest, i.e., you touch them, you touch the development of the brain and vice versa.

Ben10 said...

Actually, we can also correlate the many different instinctive behaviors (brain hardwiring) of dogs of different breed, with the many different coat colors (melanocytes patterns derived from neural crest) and shape of dogs breeds (also mostly neural crest for the face).
Maybe it's just a coincidence, but at least it's consistent with the hypothesis that when brain functions coding for behaviors are modified, visible developmental features coming from neural crest derivatives, in particular melanocyte migration, are also modified.
So that perhaps it means that it is difficult to touch one without touching the other.

I have the example of my two dogs, one has a retriever behavior, the other a herding behavior. The farm dog actually bites the other dog to the leg like he was regrouping a sheep. The retriever is black and the farm boy is white, but I doubt that the humans who bred the dogs for their specific behaviors cared much for the coat color. To me, it came as a side effect of the behavior selection.

Anonymous said...

@PFrost

"It's not clear to me why you feel it's important that the Mesolithic hunter-gatherers of Western Europe were light-skinned."

It's not if they were. They must have been at one point. It's *when* the change occurred.

"they must have become light-skinned through a very different suite of genetic changes. They thus tell us nothing about the evolution of white skin among the ancestors of present-day Europeans."

or if it was Neanderthal admixture then maybe it tells us a lot.

.

@anon

"This is why the extremely rare northern europeans without the near eastern SLC24A5 allele are not any darker than those having it. The fact that these people have never been seen is of no consequence. Lack of evidence is not evidence of lacking."

If correct they will have been seen just not noticed as such.

.

"Light eyes and light skin and light hair go together. Modern people with light eyes also have the lightest skin and lightest hair. This fact is clearly undeniable evidence that the first people with light eyes also had light skin. Haven't you seen the statistics on this? They even go back to the 18 and 1900s, and come from places like Germany."

Hair, skin and eye colors do *tend* to follow patterns most of the time which as they are the result of varying levels of depigmentation is not too surprising as there may be *additive* effects.

Secondly there is an odd distribution: more blond and blue to the northeast, more red and green to the northwest. There is no explanation for this distribution from the current model

.

"Heck, northeast asians have light skin too, and they don't even have the light eyes and hair yet."

Quite. They don't have light hair and eyes. So why do Europeans?

.

"When the farmers moved in, they brought their own middle eastern light skin genes, but they just coincidentally drifted to 100% frequency. They have virtually no effect on skin coloration in people already carrying the mesolithic european skin lightening genes."

Iodine - among other things.

.

Even if La Brana was brown it still asks as many questions as answers.

Peter Fros_ said...

Barak,

The derived alleles at three genes -- SLC45A2, SLC24A5, and TYRP1 -- account for most of the whitening of European skin. The derived allele at SLC24A5 alone accounts for 25 to 40% of the skin color difference between Europeans and West Africans. If we limit ourselves to the difference between white skin and ancestral brown skin, the percentage would be higher.

But, yes, there is a small residual difference that seems to be due to other genes, apparently many different genes of small effect. Could these small-effect genes provide an alternate evolutionary pathway to white skin? Unlikely, since the selection pressure that would have mobilized all of those small-effect genes would have also mobilized some large-effect genes. Where are those large-effect genes? Or have they completely (and conveniently) disappeared?

Again, what difference does it make to you whether La Brana was brown, white, or unknown? You seem to be arguing that present-day Europeans are white because they are mostly descended from Middle Eastern farmers who had become white in the Middle East. So what is the relevance of this alternate (and hypothetical) evolutionary pathway towards white skin?

I'm just trying to understand your argument. (And please don't use caps. I can read lower-case letters).

Peter Fros_ said...

Anon,

"This is why the extremely rare northern europeans without the near eastern SLC24A5 allele are not any darker than those having it."

This is indeed surprising. Can you supply a reference?

If the derived SLC24A5 allele is of Near Eastern origin, we are faced with a paradox, since it swept to fixation at a time when the Near East was inhabited by people who were not ancestral to Neolithic Middle Easterners.


ben10 said...

pet cats have also a large variety of eyes color: green blue yellow...
what's the explanation?

Sean said...

"It also appears that the changes to hair, eye, and skin color did not happen simultaneously. First came the diversification of eye color and then the diversification of hair color. Parallel to these changes, and extending over a longer time, was the whitening of skin color"

That may because the highest intensity of sexual selection is required for white skin. Or, white skin may have have spread originally, because it induced care and provisioning.

Anonymous said...

Genetiker has no clue what he's talking about.

Anatolian, Indo-Iranian and Greek are far more important for reconstruction of PIE than Baltic, precisely because they were attested relatively close to the breakup of PIE, which originated on the steppe north of the Black Sea and the Caucasus. Yes, Baltic remained more conservative in some respects than the other branches because of its location. So?

Paleolithic continuity theories are rubbish, both linguistically and genetically as we conclusively know now.

Gottlieb said...

''pet cats have also a large variety of eyes color: green blue yellow...
what's the explanation?''

My explanation for this is too simplistic . It would be natural variation . What I 'm trying to understand is how is the mechanism of mutations . We know that most mutations are random , but there is no Lamarckian mechanisms to create potential environmental adaptations then other processes may occur.
We know that evolution is based on trials, errors and successes . Combinations that are over time diminish the quantity, where the non-adapted types are eliminated by natural selection . But how mutations occur ?
I think the mutations are as errors of the initial design . Think of an architectural project that over time , during construction will undergoing a transformation of its initial design . Mutations are errors , such as autism , schizophrenia , flat feet , very tall people. The human being is a mutation , a bug in the initial design for primates , which in turn are also bugs of its predecessors . God is apathy , inertia....
But in a super reality (extreme rational thinking) there not ''errors'' or ''successes''.

JayMan said...

So now Eastern Europeans had dark skin in the past, too?

Dr. Frost, I'd love to see your comments on this:

Dienekes’ Anthropology Blog: Dark pigmentation of Eneolithic and Bronze Age kurgan groups from eastern Europe