Perhaps we will find a plague from when blue eyes spread, but this was way after they were common in Europe.
While all blue-eyed people share a common ancestor, Cheddar Man shows that the previous estimates of it arising in the past 10,000 years was wrong. Not too long ago it was thought the trait originated 10,000 years ago near the black sea, but the date is much earlier than that. It was probably some place after those people turned left after leaving Africa unlike skin color which is a unique combination of multiple genes, that did become in Europe later but most of the mutations probably traveled with those people from Africa.
When you have multiple genes in play plus a mutation tracing it becomes harder.
That connects people from what is now around borders of Russia, China, Mongolia and Kazakhstan with European migrants?
We can extend the discussion to the migration of people across the world, but unless you are claiming that the specific populations that resulted in these traits were from the Enets, Nenets, or the Huns it is immaterial. There were migrations but not until much later.
Note I did read your cite, and while the origin of the a few of the light-pigmentation alleles would require revision after my cite above,
Siberian and East Asian populations shared 38% of their ancestry with a 45,000-yr-old Ust’-Ishim. If you go that far back North Eurasians (ANE) are the ancestors of Western Siberians, Europeans, and indigenous Americans, so to claim it directly for the mutations that arose in later Europeans becomes problematic.
But note the opening paragraph of your above cite:
(emphasis mine)
And also note:
Note that 14,000 BP number is in Hamburg, and note Figure S.1.1. Nothing in this paper conflicts with my claims.
The authors are quite clear about the speculative nature of some of their claims. But they are also speculating it was selected for and not drift from the start.
Note the “may have” portion showing that this is a speculative claim. They are working off the presumed “selected for” theory, but can you explain why you think this is hard proof of that?
Your cite actually calls out my claims that both hair and eye color could have been due to drift.
The researchers seem completely aware of and in fact go to great lengths to point out the speculative nature of their claims.
So you are not saying that Siberia was only populated about 10 000 years ago, and you are not saying that Siberia was re-populated after people were pushed out by the last glacial maximum?
Ok, I think we may have been talking past each other. Now, I am not quite sure where the relevance of Ust’-Ishim is. To one of the hunter-gatherers of 13 000 BC, Ust’-Ishim was twice as far in the past as that hunter gather is to us. Ust’-Ishim was from about 45 000 years ago, as opposed to 14-15 000 years ago for this particular lot. You of course know that Siberia is big. I mean, utterly huge. Its more than twice the size of Europe, excluding Russia. Given an area that size and a time span that long, we would expect a lot of variety.
There was a selection in a population that arose from a mixture of dark and light skin genes. The Western hunter-gatherers were dark skinned. The light-skinned variants are pretty old, and did not come with the WHG lot. Scandinavian Hunter-gatherers are generally modeled as a mix of Eastern and Western hunter-gatherers. And these genes did not come from the Western lot.
It is quite true though that the selection appears to have continued and the SHGs and later demonstrate higher allele frequencies than the EHGs.
I suppose you could hypothesize that the genes were present at very low frequencies and only experienced selection once in Scandinavia. This does not seem like a likely explanation though, given that they seem to have appeared with the migration of a people from the east and down through the norther coast of Scandinavia which presumably had experienced the same latitude and environmental pressures for a significant period beforehand. Presumably far longer than the amount of time the Scandinavian selection took.
We could also look at my first cite which has a section titled : “Phenotypically informative markers in hunter-gatherer populations (pages 50-54)” where they report in the “Pigmentation” section that EHG had, from what I cant see from the figures, SLC24A5 completly fixed in the EHG population, and SLC45A2 at ~75 %. Only slightly less than todays northern europeans.
Interestingly, they report the blue eyes allele at 50 % in the EHG samples, which I hadn’t noticed before.
Admittedly, I am not sure which samples or what coverage they are basing this on, since the paper is the genomic history of southeastern Europe they don’t seem to reference the sources for the EHG and SHG that I can see.
When looking, I did find another interesting tidbit though: The blue eyes allele has shown a extreme and persistent north - south gradient in allele frequency that has been persistent through the last 8 000 years, leading to speculations that it may be advantageous in the north and disadvantageous in the south.
Since the zombie has been resurrected, I would like to add something. The simple story of blue recessive, brown dominant is too simple. I have light blue eyes, my wife has hazel. If you look more closely, her eyes are mainly blue with some scattered flecks of brown. Our two sons have blue eyes, but our daughter has brown eyes. If you look more closely, her eyes are not pure brown but densely flecked with brown.
Since I erased given the above correlation had already been noted I am quoting it to point out the potential contribution to why the gene spread.
The article I had -
The genes for light eyes and genes for alcohol dependency/overuse disorder are linked
a tight genetic linkage between the OCA2 gene and a nearby gene encoding a cluster of γ-amino butyric acid (GABA) receptor genes, including the GABRG3 gene (See Figure 2). GABA receptors have been implicated in alcohol tolerance and alcohol dependency,14,15 and surveys for genes associated with alcoholism identified GABRG3.16,17 GABA is a major inhibitory neurotransmitter, so a mutation in a brain GABA receptor that reduced its ability to respond to GABA might impair an inhibitory response to alcohol. This would explain why people with such a mutation might continue drinking when others stop. One hypothesis is that the OCA2 blue-eye mutation resulting in blue eyes occurred on a chromosome that already carried a GABRG3 mutation. Since the OCA2 and GABRG3 genes are separated by only about 0.2% of the length of chromosome 15, the chromosomal coupling of a blue-eyed variant of OCA2 and an alcohol tolerant GABRG3 variant has been maintained in most descendents of the first blue-eyed human.
Individuals with light eyes apparently tended to also be individuals who “might continue drinking when others stop” … facilitating ancient hook ups!
Those of us who are lactose intolerant can generally consume some milk, and before lactase persistence emerged many people did. Consume too much and they would get gassy and some diarrhea. Unless of course it was also at a time of famine. Then that diarrhea would be enough to push you over the edge and kill you. The combination of famine with lactase persistence in a population that was already drinking milk is what turbocharged its spread.
I’m glad this thread was bumped, because i missed some of the older posts, too.
Oh, that’s two different cites! I have seen milk paint, it was commonly used on historic buildings around here. But the evidence it was used before the domestication of dairy animals is amazing!
Still, i doubt anyone was moved to make cheese too keep their painting materials around.
This:
Seems more likely to me as a path for lacrosse intolerant adults to develop cheese. There are a lot of other complex processes to render foods safe to eat, and hard cheese are generally nutritious even if you can’t produce lactase.
In fact, before reading this thread, i had assumed it was linked to skin color, which is more obviously differentially advantageous by latitude.
Speaking as a blue-eyed individual who hates to get drunk, and stops drinking long before others stop, this is not a very strong link. There may be some statistical correlation, but those traits don’t go hand in hand.
Oh sure. But when you say that traits are linked, that can mean a wide variety of things, from “slightly increased chance of occurring together” to “mediated by the same gene, and almost always occur together”.
I’m just saying I’m pretty sure it isn’t the latter.
No, it’s not quite like that - you make the paint, and then in some desperate time you figure out ‘hey, I can also eat this stuff’ - or at least the precursor stuff - casein glue is basically (heh!) curds+alkali. But you wouldn’t make cheese to preserve your casein, better to dry the curds out completely and make casein powder.
