Ancient DNA and the human past

I've been questioning and discussing that Vitamin D/light skin hypothesis with my MD and Scientist friends for 30years...it just doesn't make sense on human evolutionary time scale, there has to be something else at work...

 

Sure........blame the Russians.

 

assigning names of modern populations to ancient peoples was clearly an error, those who comprehend what's being discussed know they're not talking about today's russians...those who aren't reasonably versed in genetics will take such comments literally...

 

that's physically and mathematically impossible...

 

Genes for lighter skin appear to have evolved separately in Neanderthals and modern humans - selected for by the same conditions - a northern climate with less sunlight as well as diet.

 

the genetic evidence doesn't support that, it contradicts that.
the change from dark to light skin was recent, in the last 10K years....so for at least 20-30k years since the arrival of modern man in the northern latitudes there was no change in skin colour and they survived with less sunlight and the same diet ....there's something else at play here that's been overlooked or as yet not identified...

 

Not according to studies I've read but I am certainly willing to entertain any more recent information you have.

I did some interesting research on ancient migrations and this subject came up as a side.

 

A couple of articles that may shed light on this:

https://www.newscientist.com/article/dn22308-europeans-did-not-inherit-pale-skins-from-neanderthals/

https://www.sciencemag.org/news/2015/04/how-europeans-evolved-white-skin

 

very good articles but not sure how much light that sheds on the issue, it seems to confirm what i saying, it's not as simple as some would make it out...there are a number of contradictions

pale skin is advantageous in northern latitudes-homo sapiens and and some neanderthals had dark skins for a very long period of time without any ill effects, for sapiens at least 20-30years and for some neanderthals perhaps a couple of hundred thousand...what was the sudden drive for beneficial adaptation, why so late?

vitamin D-the Inuit dark skinned, gain their Vitamin D from their food, whereas the Sami of northern europe are light skinned and they also gain large amount of Vitamin D from their food

-both of these people keep themselves covered because of the cold or protection from clouds of biting insects that inhabit northern latitudes in summer, where is the benefit in pale skin if it never sees the sun?...

-the sami use Reindeer milk about 27% being lactose intolerant, 80% of inuit are lactose intolerant and they don't milk the Caribou...

-vitamin D deficiency is also found in equatorial regions where clothing is often optional and sunshine is in abundance...

-is it possible that pale skin may tag along on a gene that indicates lactose tolerance but not of any benefit to the individual...this has been observed in domestication in animals, a trait that is desired is accompanied by traits that were not intended....

-animal domestication for behaviour came with curly tails, floppy ears and unusual colour patterns though the later three traits weren't the objective...so in breeding for docile behaviour other physical traits appear to have tagged along

-sexual selection must play a part but how much?

-is skin colour an advantageous adaptation to prevent skin damage from intense sunlight in equatorial regions where all sapiens originated ...then possible lost when it was no longer required ?...like whales with remnant legs, some have vestigial legs but they have no need of them but they don't hurt the whales chances of survival either...

-blond hair and blue eyes appear to have arrived at approximately the same time as light skin that much seem clear

-blond hair isn't exclusive to light skinned northern europeans, it's also found in dark skinned people of the south west pacific but connected to a different gene than it is in europeans

I've don't have any hard answers just lots of questions and contradictions

 

Don't forget that for most of the time they were intermingling, Neanderthals and humans were living mostly in the Near East with a more moderate climate. Neanderthals actually migrated to northern Europe during an inter-glacial period where they evolved lighter skin and reddish complexions which were quite different to skin tones in the Middle East.

Modern humans were really not able to live in northern Europe until the last glaciation really started to recede perhaps 10 to 15,000 ya. You are correct that we don't have a great genetic timeline for the development of lighter skin but that time period is not out of line with what we would expect for selection of favorable traits.

Indeed......well, you could look at the founder effect in the genetic makeup of both Sami and Inuit. I would not be too far-fetched to say that the north-Asian gene set that the Inuit brought with them to North America may have been somewhat prohibitive to adaption of light skin whereby the Same more adaptive to change do to a more European background with less influence from Asian gene pools. Still, you make some good points. I don't think we can get the full story without understanding the genetics better.

Still, on a general basis I think you can say that there is a fairly strong correlation between latitude one lives at and skin colour while still keeping in mind that admixture of populations muddies these waters to a degree that limits our understanding:

"Credit for describing the relationship between latitude and skin color in modern humans is usually ascribed to an Italian geographer, Renato Basutti, whose widely reproduced “skin color maps” illustrate the correlation of darker skin with equatorial proximity (Figure 2). More recent studies by physical anthropologists have substantiated and extended these observations; a recent review and analysis of data from more than 100 populations (Relethford 1997) found that skin reflectance is lowest at the equator, then gradually increases, about 8% per 10° of latitude in the Northern Hemisphere and about 4% per 10° of latitude in the Southern Hemisphere. This pattern is inversely correlated with levels of UV irradiation, which are greater in the Southern than in the Northern Hemisphere. An important caveat is that we do not know how patterns of UV irradiation have changed over time; more importantly, we do not know when skin color is likely to have evolved, with multiple migrations out of Africa and extensive genetic interchange over the last 500,000 years (Templeton 2002). "




https://www.ncbi.nlm.nih.gov/pmc/articles/PMC212702/

My understanding is that genes often are selected for and distributed in systems that we don't really understand that well so "tagging along" may well happen.

Asking questions and studying contradictions is a good thing. It interesting to me that the genetic advantage to lighter skin in northern climes and even eye-colour and hair seem to have popped up as a solution to problems of protections from UV and vitamin D deficiency multiple times in response to similar environmental conditions if that is what is happening.

As you say, I don't think we know the full story, by any means.

 

from one of your links "a study earlier this year of ancient DNA suggested that Neanderthals living in what is now Croatia had dark skin and brown hair." so even northern neanderthals had light skin, could sexual selection/isolation be a factor more than latitude?...even people of southerly latitudes of middle east have comparably light skin.

agreed but what is the main driver of this change or are there several some of which are unintentional and coincidental.




View attachment 79208

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC212702/

according to that graphic Europeans appear to be an outlier, other populations have been in northern latitudes for as long but never reached the European level of light skin

and are we even asking the right questions?.

the common assumption is pale skin is adaptation but what if dark skin is the adaptation?...and the adaptation isn't for vitamin absorption but primarily for protection from UV radiation...our earliest ancestors were covered in fur, as they became bipedal fur was a hindrance as it prevented heat regulation for running, we rely on sweating to cool our bodies, distance running was our competitive survival advantage in an environment filled with dangerous carnivores ...a light skinned hairless running ape in the plains of Africa would be in danger of fatal infection due to UV burns...looking at your graphic notice the return to darker skin of indigenous people in the Americas in the southern latitudes, maybe we have the process backwards...what if light skin is the default colour?...in northern latitudes with populations fully covered to stay warm UV burns aren't much of an issue so perhaps like whales losing their legs the extra skin pigmentation isn't required for UV protection, our diet supplied the required vitamin D ...and now sexual selection plays a greater role...

it's so complex, every explanation spurs more questions.

 

Yes, DEAR
But at what expense?
Black encourages the absorption of the heat of sun light.

Maybe a rethink.
Black just happened parallel with going hairless.
Why go hairless.

BTW I believe Neanderthal was the first ancient to have grandparents.
The rest of them before, didn't live so long, so could UV have been a factor?

I like Aquatic Ape theory myself.​

Subcutaneous fat. Only aquatic mammals got it as we do. Apes do not.

Atavism Happens​

 

How far back y'wanna go?
The precursors of "out of Africa"
migrated in from Asia.

And we don't have much on ancient Asian physical anthropology.
Bamboo replacing many stone implements not preserved like stone.
Chinese anthropologist like, "continuity through continuous hybridization"
vs the Western "species replacement".
They also claim their more modern H. erectus demonstrate
Asiatic cheek bone flattening.
I'd like to see more searching for the earliest Asian people like critter.



Remember, Denisovan is a hybrid.
Some this, some that, some not ID'ed = ultra ancient
Living in groups of 20 - 30 makes "outbreeding" a terrific cultural advance.
Or was it sexual selection/attractiveness of the stranger. The exotic.



Moi

Look where the Lord
placed ​

 

You should look into this study: Ancient Fennoscandian genomes reveal origin and spread of Siberian ancestry in Europe. The Siberian admixture of northern Europe traces back to migrations from Siberia that began at least 3,500 years ago. This ancestry was subsequently admixed into many modern populations in the region, in particular populations speaking Uralic languages today. Ashkenazi Jews have lived in the region for more than 1,500 years to acquire this genetic makeup. Y-haplogroup N1c is the genetic maker for this ancestry, which is particularly common in Finland.

 

Fits Moi's Theory of the Altaic Language Group without "pure bred Altaics".
From what I understand of the grammar structure, it is relatively simplified
such as English evolved from the Danish guy trying to talk to his Saxon wife.
Their words were similar enough, etc. But, each other's grammar
Drop gender & cases, easy plurals and the importance of the preposition.
Simplified grammar that I apply to Altaic.


When the globe dried up , Younger Dryas episode,
survivors retreated to the great rivers, Nile, Indus, Euphrates, Yellow, Amazon, Mississippi, etc.
or went polar.
Various "peoples" settled polar and proto Altaic became their language.
They domesticated reindeer. The horse was not just a major step for future Turkic & Mongol types.

How does that fit with you @ThirdTerm

 

Hey mike.... I don’t want to intrude on your discussion ,and do not have a pony in this race

That said, they are pushing back the out of Africa dates much earlier than 50,000 years. They have found skulls in greece dared about 200,000 years ago
https://www.businessinsider.com/modern-human-skull-210000-years-old-in-greek-cave-2019-7

.... and if course, as you say, many other remains dated more than 40,000 years ago
Here is another from israel
https://www.independent.co.uk/news/...-outside-africa-israel-tel-aviv-a8177711.html

The idea of the original post that modern humans came out of africa less than 10,000 years ago seems dubious at best.

 

Correct.

What about the "humans" in Eurasia 50,000 years ago?
From Peking to Germany.
Did Asiatic Humans evolve "Asiatic Eyelids" in 50,000 years?


For a good time, consider
https://en.wikipedia.org/wiki/Dmanisi
1.8 Million Years ago. Give or take
Skulls with such diversity from one another that
had they been found at separate locations would not
have been considered the same "species".


@Lil Mike
Remember, They Cannot Be Trusted!
http://politicalforum.com/index.php?threads/can-they-be-trusted.513616/



psst, Continuity Through Continuous Hybridization
Who needs a stone age when you got bamboo?


And Simians did originate in Asia.

 

Ignore the above because i did not understand the original post

 

Well clearly there were multiple incursions of humans out of Africa earlier. That's where the Neanderthals and Denisovans come from. But the current theory suggests that the version of homo sapiens that settled the rest of the planet left Africa about 50,000 years ago and either killed off or interbred with the other human groups that had left earlier.

Of course, new data could change that theory.

 

I'm reminded of the "Ape Woman", found living wild in Russia in the 19thC. Recent DNA work on her ancestors revealed she was African, but not a modern one. She was from a group which migrated east around 100,000 years ago.

Apparently she had no common language with her 'captors', and to those who knew her, was very primitive.

 

No but the Folate theory has much more weight

 

Yes, lots of uncertainty to investigate
One interesting thing i had heard was that African populations have massive genetic diversity. ... much more than europe or Asia

 

I think the Bantu expansion has taken care of that. There are still vestigial populations like the Khosian and pygmy groups but a lot of that genetic diversity has been diminished.

 

Judge for yourself

https://www.bing.com/search?q=human...8-0&sk=&cvid=C2E1121AFBD640998CA99F0DCC51A4C0

 

Yea, but H. Erectus went extinct around 70,000 years ago at the latest. The majority of that species died off almost 300,000 years ago other than a few groups which had become isolated. So there are gigantic gaps if your theory is to be believed. As in at least 20,000 years at a minimum.

And the reason is not any kind of contact, it is called convergent evolution. Hench why the "Saber Tooth" have evolved, died off, then evolved yet again. At least 7 different times in fact. 5 times it evolved then vanished to return in reptiles. THen 2 more times in mammals.

Here below is Barbourofelis fricki, from 13.6 to 5.6 MYA.



Then you have Smilodon, which is what most people actually think of. It evolved at around 2.5 MYA, and survived until around 10 kya.



Do not confuse convergent evolution with evolution itself. Animals (even humans) in the same locations are going to generally evolve the same traits over and over again.