How Europeans evolved white skin (2015) • Hacker News Board

Re: How Europeans evolved white skin (2015)

#31

Post by zeotroph » Sat, Mar 17, 2018, 5:14 PM UTC

defen wrote: post #21

Milk does not naturally contain very much vitamin D, so that's a silly reason to expect lactase persistence to have evolved. A much simpler explanation is that it massively increases the calories available to pastoralist populations. SLC24A5 is an interesting gene - I don't think Vitamin D is the full story. It's an SNP that is alone responsible for 25-40% of skin tone difference between Europeans and West Africans,…

> vitamin D

That is the driving force for lighter skin (unless your diet is mostly fish, such as the Inuit). Skin gets darker again when migration towards sunnier climates happens: while UV light is essential for the synthesis of D3, it also destroys folic acid / vitamin B9 [1], which is essential when the neural tube of a fetus is being formed.

And since this mutation is so very visible, maybe here sexual selection plays a role, just like it is suspected with blond hair?

1: https://www.sciencedaily.com/releases/2014/03/140321095240.h...

Re: How Europeans evolved white skin (2015)

#32

Post by gumby » Sat, Mar 17, 2018, 5:15 PM UTC

alejohausner wrote: post #3

So vitamin D is the driving factor: either you lose melanin, or become lactose tolerant, or you die. With dark skin, you can't make enough D from sunlight. If you can't drink milk, you can't get it from diet. Either way, ancient Northern Europeans had to mutate into pale-skinned milk drinkers, because their land is not very sunny. Cool.

If you click on the study you'll see that this point is really an artifact of the summary article, not the actual study.

Re: How Europeans evolved white skin (2015)

#33

Post by gumby » Sat, Mar 17, 2018, 5:17 PM UTC

amriksohata wrote: post #4

I'm struggling to understand this, tallness? Didn't that only happen to some European countries in the past hundred years? Because of diet? The ability to digest milk? The Hindu civilisation is one of the oldest in the world and milk and cows are very much a first class thing, suggesting it's not jsut Europeans that could digest milk, but other culture for a very long time. Maybe I'm reading this wrong but how does t…

> suggesting it's not jsut Europeans that could digest milk, but other culture for a very long time.

The same flood of people moved into Europe, the Indian subcontinent and Persia around the same time, bringing genes, language, religion etc with them.

(They presumably went elsewhere too with less success.)

> Maybe I'm reading this wrong but how does this explain the colour difference between black people and Asian people?

It doesn't; you're reading the summary title correctly but that doesn't reflect what the study actually says.

The study finds evidence that the general european population acquired a light skin and some other traits due to an influx of people carrying a bunch of genetic, linguistic and cultural traits who arrived about 4500 years ago. (Some of those same people are believed to have also headed around the same time in India and Persia, among other places). The study notes that there were already light skinned people in scandinavia around the same time.

So it doesn't explain "how", just points out evidence that most European dwellers (including those in the British Isles) were dark skinned until fairly recently, unlike the dioramas one finds in museums.

Re: How Europeans evolved white skin (2015)

#34

Post by Profragile » Sat, Mar 17, 2018, 5:21 PM UTC

giardini wrote: post #19

I was surprised to see the article state "The modern humans who came out of Africa to originally settle Europe about 40,000 years are presumed to have had dark skin, which is advantageous in sunny latitudes." "presumed"??!! I've always thought there was some scientific evidence for this and not mere presumption. Is there not some evidence about the skin coloration of our African ancestors of different periods?

No, because there is NO WAY Europeans came directly from Africans. There is no similarity, no common language, nothing to suggest that there was a close relationship between Africans and Europeans. On the other hand, Europeans have much more similarity with certain Arabic tribes.

Re: How Europeans evolved white skin (2015)

#35

Post by lerie82 » Sat, Mar 17, 2018, 5:24 PM UTC

so basically the more youre in the sun, the darker your skin gets, thanks science.

Re: How Europeans evolved white skin (2015)

#36

Post by quotemstr » Sat, Mar 17, 2018, 5:33 PM UTC

drb91 wrote: post #27

_emacsomancer_ wrote: post #22

Earlier quoted context omitted.

Some of this is tricky to untangle, because it's easy to intentionally or unintentionally conflate genetics/race, culture, and language, but at least culturally/linguistically the people of North India are related to the majority of the peoples of Europe. So Sanskrit, Hindi/Urdu, Bengali, Gujarati, Punjabi, Kashmiri, Assamese, Nepali etc. are all Indo-European languages, as are Latin, Greek, Russian, Danish, Icelandi…

Just to be clear, the Indo European migration is presumed to be a trade/culture migration—there’s not a lot (any?) evidence that this resulted in much increased genetic transfer. Furthermore, I was under the impression milk consumption generally spread from the middle east with rudimentary cheese production with rennet, reducing the lactase to an easier to digest level. This might have been after the europeans starte…

> Just to be clear, the Indo European migration is presumed to be a trade/culture migration

Not the case. You're making the "pots, not people" case, which ancient DNA evidence has thoroughly debunked. Changes in material culture usually do indicate large-scale population movements. Yamnaya remains from the Caucuses, for example, are genetically almost identical to the ones buried in the Corded Ware culture that spread through Europe ~5000 years before present. The Yamnaya, a steppe people, completely overran Europe, and today, contribute just over 50% of the ancestry of Western European populations and who spread Indo-European languages there and elsewhere.

The idea that prehistory was full of peace, love, and gradual and voluntary cultural change is ridiculous and indefensible, especially in light of modern genetic evidence, but also on the grounds of common sense.

Why wouldn't you expect to see large scale folk migrations? We have historical records of large-scale movements (e.g., Germanic tribes from Tacitus), and one would expect similar movements, of even greater scope and intensity, to have occurred in prehistory. This kind of movement was the norm, not the exception, in prehistory.

Post-1970s thought in this area seriously annoys me. It presumes a gradual, peaceful transition everywhere at all times despite stark evidence to the contrary. Read Ward-Perkins for a good rant on how fellow historians believe, against all historical and archaeological evidence, that Rome never fell. He's as frustrated and baffled by this thinking as I am.

Re: How Europeans evolved white skin (2015)

#37

Post by quotemstr » Sat, Mar 17, 2018, 5:39 PM UTC

amriksohata wrote: post #26

_emacsomancer_ wrote: post #22

Earlier quoted context omitted.

Some of this is tricky to untangle, because it's easy to intentionally or unintentionally conflate genetics/race, culture, and language, but at least culturally/linguistically the people of North India are related to the majority of the peoples of Europe. So Sanskrit, Hindi/Urdu, Bengali, Gujarati, Punjabi, Kashmiri, Assamese, Nepali etc. are all Indo-European languages, as are Latin, Greek, Russian, Danish, Icelandi…

Are you referring to the Aryan invasion theory? If so that's been debunked a long time ago

No it wasn't

Re: How Europeans evolved white skin (2015)

#38

Post by trhway » Sat, Mar 17, 2018, 5:42 PM UTC

alejohausner wrote: post #3

So vitamin D is the driving factor: either you lose melanin, or become lactose tolerant, or you die. With dark skin, you can't make enough D from sunlight. If you can't drink milk, you can't get it from diet. Either way, ancient Northern Europeans had to mutate into pale-skinned milk drinkers, because their land is not very sunny. Cool.

Milk is calcium. Colder climate - bigger body. That needs calcium. Thus milk and vitamin D, both are necessary. Thus pale skin and lactose. Either alone isn't enough.

Re: How Europeans evolved white skin (2015)

#39

Post by freehunter » Sat, Mar 17, 2018, 5:55 PM UTC

giardini wrote: post #19

I was surprised to see the article state "The modern humans who came out of Africa to originally settle Europe about 40,000 years are presumed to have had dark skin, which is advantageous in sunny latitudes." "presumed"??!! I've always thought there was some scientific evidence for this and not mere presumption. Is there not some evidence about the skin coloration of our African ancestors of different periods?

To say the least, it's kind of difficult to scientifically prove the skin color of someone from 40,000 years ago. Fossilized bones don't tell you if someone was black or white or whatever. We're not even entirely sure what skin color ancient Egyptians had.

Much of what we know about pre-history is educated guesses based on a tiny amount of evidence and a lot of critical thinking.

Re: How Europeans evolved white skin (2015)

#40

Post by _emacsomancer_ » Sat, Mar 17, 2018, 5:56 PM UTC

amriksohata wrote: post #26

_emacsomancer_ wrote: post #22

Earlier quoted context omitted.

Some of this is tricky to untangle, because it's easy to intentionally or unintentionally conflate genetics/race, culture, and language, but at least culturally/linguistically the people of North India are related to the majority of the peoples of Europe. So Sanskrit, Hindi/Urdu, Bengali, Gujarati, Punjabi, Kashmiri, Assamese, Nepali etc. are all Indo-European languages, as are Latin, Greek, Russian, Danish, Icelandi…

Are you referring to the Aryan invasion theory? If so that's been debunked a long time ago

The nature of the entry of Indo-Aryan speakers into India has been discussed in more nuanced ways, but the relation of Sanskrit et al. to European languages (and the unrelatedness of Indo-Aryan to Dravidian and Munda and so) is all well established and not under debate. Either Indo-Aryan speakers migrated into India from outside, or all of the other Indo-European groups migrated out of India. The latter, while not completely out of the question, is much less likely than the former.