Did humans leave Africa earlier than previously thought? Discovery of ancient tools in China

Adam

(Guy Coe) #21

Thanks, George; that is helpful. I guess the presumption should be that it was beneficial for populations in the region when and where the variation was fixed?


(George) #22

@Guy_Coe

I’ve always wanted to know where Beringia was!
“The term Beringia was coined by the Swedish botanist Eric Hultén in 1937.”

Apparently waders are recommended for the modern tourist!

[quote from the Wiki article on the 370A mutation]
"It has been hypothesized that natural selection favored this allele during the last ice age in a population of people living in isolation in Beringia, as it may play a role in the synthesis of breast milk under Vitamin D-poor conditions.[10][11][12] The 370A mutation arose in humans approximately 30,000 years ago, and now is found in 93% of Han Chinese and in the majority of people in nearby Asian populations. "


(Jon Garvey) #23

I never realised the Chinese had breast milk in tears… oh, I see, the eyes are a spandrel. Nothing’s ever straightforward is it? You ask someone why their eyes are that shape and they smile inscrutably and say “lactation.”

In other news (but the same area) polar bears became white to prevent Vitamin A poisoning from all that blubber.


(George) #24

@jongarvey

According to the report described in the NY Times article… it may not have anything to do with the eyes - - that was a surprise for me to read …

"The finding that the gene has so many effects raises the question of which one was the dominant trigger for natural selection.

Dr. Sabeti said the extra sweat glands could have been the feature favored by natural selection, with all the other effects being dragged along in its train.

“We’re the only mammals to have changed their entire hair pattern. So the changes in teeth, hair and breasts — it’s very possible they are the passengers and thermoregulation is the key,” she said, referring to the role of sweat glands in cooling the body."

“East Asians are sometimes assumed to have evolved in a cold environment because of their narrow nostrils, which conserve heat, and the extra eyelid fat that insulates the eye. But the Broad team calculates that the EDAR variant arose about 35,000 years ago in central China and that the region was then quite warm and humid. Extra sweat glands would have been advantageous to the hunter-gatherers who lived at that time.”

[truncated text - - lots more in the article]


(S. Joshua Swamidass) #25

This is a reference to neutral draft, a well established neutral process.


(George) #26

1655 AD: Isaac La Peyrère wrote: Prae-Adamitae:

The 17th-century French Millenarian Isaac La Peyrère, because of his influence on subsequent thinkers and movements, is usually credited with formulating the pre-Adamite theory. In his Prae-Adamitae, published in Latin in 1655, La Peyrère argued that Paul’s words in Romans 5:12-14 should be interpreted to mean that “if Adam sinned in a morally meaningful sense there must have been an Adamic law according to which he sinned. If law began with Adam, there must have been a lawless world before Adam, containing people.”[11] Thus, according to La Peyrère, there must have been two creations; first the creation of the Gentiles and then the creation of Adam, who was the father of the Hebrews. The existence of pre-Adamites, La Peyrère argued, explained Cain’s taking of a wife and the building of a city after Abel’s murder in the Book of Genesis.

.
.

.
.

I don’t remember why Isaac La Peyrere is not considered an integral part of the timeline found in another thread… especially since he titled his work “Pre-Adams” (see Romance title above).

Here is the link to the main thread for the Timeline (a work in progress… first we are collecting the individuals…)


(S. Joshua Swamidass) #29

No @gbrooks9 la peyrere does not count. We will move him to different thread. This is important to get right.


(Jon Garvey) #31

He was very much in my thought when I was first thinking about what is now called “Genealogical Adam”. A guy called Dick Fischer, who argued for an Adam in the early days of Eridu, drew from him. David Livingstone (not the missionary) wrote a book on pre-adamism which deals with his work (and which Joshua has referenced).

Apart from raising the possibility of man before Adam, his work is probably peripheral, being dubious as biblical exposition, and mosttly responsible for justifying early anthropological views on European racial superiority.


(Guy Coe) #32

I have a book by Dick Fischer; will examine it for signs of same.


(Jon Garvey) #33

Guy - my remarks were directed at La Peyrere, not Dick!


(Guy Coe) #34

Ahh…
LaPeyrere was the one who took “pre-Adamism” (sic) in a racist direction.
Dick Fischer’s stuff seems legit, so far.


(S. Joshua Swamidass) #35

Dick is totally confused by Genealogical ancestry. He spend hours arguing I was wrong about universal ancestry.

The only examples that count are those that see universal ancestry of humans from a recent Adam.


(Guy Coe) #36

Yes, Dick is totally (and unnecessarily) confused in just the manner you describe.


(Mark M Moore) #37

So pleased to see the term “universal ancestry”. It really makes GA clear enough to where if someone doesn’t get it, its their fault.


(George) #38

@swamidass

Could you explain this? I don’t understand what he is EXCLUDING from his list of valid scenarios?


(Mark M Moore) #39

Here is the article I would use for the title “Did humans leave Africa earlier than previously thought?” DNA testing from a Neanderthal bone found in a central Asia cave showed that this specimen’s ancestors had mated with a now-extinct human lineage 100,000 years ago.

The article keeps saying the humans came “from Africa” but I am not sure we can assume that anymore. The human DNA in this Neanderthal had signs of not being a subset of today’s African human DNA. IOW, I think its possible that humans were in Eurasia as well as Africa 100,000 years ago but only the ones in Africa survived, or at least survived in great enough numbers for their DNA to be detectable today. Maybe when the OOA group of humans came along 55K ago they met a few hangers -on from the group that was there 100K ago and swallowed them up. So long as I am speculating, I wonder if the OOA group picked up their Neanderthal genes from “pure” Neanderthals or from these earlier humans who had admixed with Neanderthals?

Edit: I really need to turn this one into a full post on its own, perhaps after this one dies down. Here are two other articles which are very interesting and relate to the idea that there was a larger human population outside of Africa 100K ago but that only the humans in Africa survived to populate the rest of the globe, or perhaps there were so few non-African humans left that their genetic contribution to living humans border on the undetectable…

And lastly here is a paper which is a more detailed look at the first link, so detailed that the nuance of the science is beyond me, but it also suggests that whatever human population hybridized with this eastern Neanderthal was not a subset of African humans, but branched at the same time or even just before the line which led to Africans…


(George) #40

@Revealed_Cosmology

I don’t quite understand your logic.

Hominids had been coming “out of Africa” in waves, over and over. Why wouldn’t there be humans in Asia or Europe 100,000 years ago?


(Guy Coe) #41

A sequential reading allows for a very old, “imago Dei” humanity, with as “recent” an Adam as is necessary, geneaologically. Sorry; just have to restate the obvious once in a while.


(George) #42

@Guy_Coe

Since you hate addressing your posts, I will assume you are speaking to Mark.


(Mark M Moore) #43

George the mainstream view recently has been that all living Eurasians came from a single wave 55K or so ago. Lately there have been some hints of an earlier population that may have left a trace at the borderline of what we can detect genetically. What I am asking is “what is the evidence that these earlier populations of humans came from Africa”? Maybe the Africans were just the one branch of a larger humanity which survived and then finally busted out. The other branches, the Eurasians that were already there 100K ago, either died out or their contribution to living humans is so small that it is not detectable.

That is what these three studies are suggesting to me. The studies don’t say that- they stick with the OOA theme, but the data in the studies suggests different in that if you go to that middle picture in that prior post of yours and look at the red arrow in the middle of Asia pointing to “25,000” then you are close to the spot where they found a Neanderthal hybridized with a human from a population that either is just as basal as the San or somewhat more basal.