Long genetic and social isolation in Neanderthals before their extinction

58 pointsposted 9 months ago
by PaulHoule

62 Comments

jamiek88

9 months ago

Wow this paper was fascinating.

Multiple Neanderthal groups in Europe geographically fairly close, on the brink of extinction, yet no interbreeding for 50,000 years.

The stories that pop into my mind!

rightbyte

9 months ago

"Fairly close", as in, "somewhere else in France, which in the year of 45000 BC, is mainly forest"?

If I read the map correctly.

usrnm

9 months ago

Our ancestors and Neanderthal ancestors for that matter came there all the way from Africa. It was definitely doable at the time

kuhewa

9 months ago

Yes several weeks. But no contact is a little surprising for fifty generations, let alone fifty thousand years.

rightbyte

9 months ago

Hmm .. ye thinking about it, it is kinda strange. Dunno how long you need to roam around until you see some other tribe by chance. But certainly not thousands of years?

escapecharacter

9 months ago

one day we’ll find the first incel cave painting. What wonders the ancient world holds!

shermantanktop

9 months ago

Grog kill mammoth with bare hand, but girls like tool-making Chad. Not fair!

fsckboy

9 months ago

it doesn't say that. too few individual remains in too few locations have been found to understand whether the groups had been living near each other for 50,000 years or what their social structures were at all. It would make sense for a species near extinction to have small population clusters migrating and not bumping into each other. They do contrast this with what is known of early modern human genomes in the same areas which do appear to be more mixed, but why wouldn't examples of a newly successful expanding population appear different from remnants of an old population dying out?

so what they found is not at odds with what you are suggesting, but there are other explanations, and not much data

kuhewa

9 months ago

> It would make sense for a species near extinction to have small population clusters migrating and not bumping into each other

What evidence do you suggest supports this for 50k years?

The group Thorin was from may have been close to extinction when he died, but when genetic isolation started they were 50k years away from being that close to extinction. It seems remarkable based on what we know of hunter gathers or even animal population structure and movement, that there would be no mixing for that long.

fsckboy

9 months ago

>What evidence do you suggest supports this for 50k years?

there is no evidence that they were near to each other for 50K years, only that their genomes diverged 50k years ago which was the last time they were near each other.

At the separate-times-and-places that they died in "France", the recent migrants may only have arrived in the last few months, having spent the previous 50K years over in that other far away place, and died only somewhat near each other a decade apart

the mixed genome of early modern humans and the lack of mixing of Neanderthals is a separate piece of evidence, and it may point to Neanderthals not being as sexy-social, but that's just a "may".

kuhewa

9 months ago

But the other contemporary lineages were mixing more than Thorin, and relatedness broadly correlates with geographic proximity [1]. But the contemporary later lineages in the area split off from samples as far as from Siberia and the Caucasus than to Thorin, as this paper demonstrates.

It isn't out of the question that groups could have moved quite a bit since there is evidence of turnover in either Caucasus or Western Europe later on, but I am not sure coming from somewhere else solves the puzzle. Existing evidence suggests that the MRCA of known late Neanderthals including those predating Thorin was in Europe [2].

So Thorin's lineage could have traveled from somewhere without other hominids and beelined for this site ten years prior, but it is not very parsimonious considering he was in a layer with the same PNII style artifacts for thousands of years before and after him? However, the PNII artifacts don't appear to be rooted in the previous ones of the region so perhaps there was an older exotic origin.

[1] https://www.nature.com/articles/nature26151 [2] https://www.science.org/doi/full/10.1126/sciadv.aaw5873

mkoubaa

9 months ago

My first thought was very disturbing, that they were bred by humans as pets.

datameta

9 months ago

We would see the heavy intermixture in one of the groups in that case. In addition, if one group was in homo sapiens captivity, then it is overwhelmingly likely that the other group would be found during those 50 thousand years (considering our propensity for migration).

danielbln

9 months ago

Or slaves.

inglor_cz

9 months ago

You don't really need slaves in a hunter and gatherer society (no agriculture, no construction, no mining = no backbreaking work that free people are loath to do), and you don't really have the institutions to keep them from running away.

As far as our observations of Stone Age people go, if they catch someone, they either kill them or make them a permanent member of the group.

brink

9 months ago

Masters have bred with slaves since the beginning of history. Abraham and Hagar, for example.

euroderf

9 months ago

> The stories that pop into my mind!

Clan of the Cave Bear ?

dyauspitr

9 months ago

Probably enslaved by humans and kept from interbreeding. Alternatively, very strong tribal culture that prevented intermixing like in the tribes in Papua New Guinea.

rightbyte

9 months ago

I don't think slavery made sense for nomadic people. Also, 'slave' is a quite advanced abstract concept for a time when humans could barely speak with eachother.

PlattypusRex

9 months ago

I'm confused by this, humans already had well-developed and complex language well before we started moving out of Africa into Europe.

underlipton

9 months ago

Relatively high divergence of language across a relatively small geographic area? How often, exactly, are you interacting with people outside your family group? Outside your local group of family groups? Even factoring in nomadism.

biorach

9 months ago

> a time when humans could barely speak with eachother.

That's a pretty wild claim

rafram

9 months ago

We don’t know anything about Neanderthal language, or even whether they had something we would consider language.

dyauspitr

9 months ago

We’re talking about the Homo sapiens here since they would be doing the enslaving.

user

9 months ago

[deleted]

fsckboy

9 months ago

tangential: the modern human genome shows remnants of Neanderthal genes indicating that there was some mixing. Do any of these Neanderthal genomes show any similar mixing in the other direction?

lapcat

9 months ago

According to the book "The Naked Neanderthal" by the paper's lead author, no.

This suggests that humans socially dominated Neanderthals when they came into contact.

The evidence does show that humans were vastly superior at making weapons.

masklinn

9 months ago

That book is definitely incorrect given we know the neanderthal "y" chromosome disappeared some 60 thousand years before neanderthals did, replaced by H. sapiens sapiens's.

H. sapiens mtDNA was also found in "recent" neanderthal remains.

lapcat

9 months ago

> That book is definitely incorrect

That's a rather bold claim about one of the world's foremost paleoanthropologists.

"When you are searching for ancient DNA [from 40,000 to 45,000 years ago] … all these early sapiens have recent Neanderthal DNA, and that's why we have [Neanderthal DNA] today. But when you reach and you try to extract DNA from the last Neanderthals, contemporaries of these early sapiens — let's say between 40,000 and 50,000 years ago — there's not a single Neanderthal with sapiens DNA." https://www.livescience.com/archaeology/simply-did-not-work-...

Keysh

9 months ago

Harris et al. 2023, “Diverse African genomes reveal selection on ancient modern human introgressions in Neanderthals” https://www.sciencedirect.com/science/article/abs/pii/S09609...

“… most Neanderthal homologous regions in sub-Saharan African populations originate from migration of AMH [anatomically modern human] populations from Africa to Eurasia ∼250 kya, and subsequent admixture with Neanderthals, resulting in ∼6% AMH ancestry in Neanderthals. These results indicate that there have been multiple migration events of AMHs out of Africa and that Neanderthal and AMH gene flow has been bi-directional.”

This is, admittedly, research published after Slimak’s book came out, and referring to an earlier time period.

lapcat

9 months ago

Yes, I think his research focuses on a more recent period, and one of the main points of the book is to refute theories about why Neanderthals became extinct, so the 250kya period wouldn't be directly relevant to that.

It's interesting that according to https://www.livescience.com/archaeology/humans-and-neanderth... "This group of humans died out".

The_Colonel

9 months ago

> This suggests that humans socially dominated Neanderthals when they came into contact.

Why? Is it because it is assumed that the dominant specie would steal the women (who would spread these traces in the dominant specie)?

Isn't it possible that the dominant specie would also just rape, but not steal the women? (which would presumably cause the opposite genetic "flow")

jaredhallen

9 months ago

I gave this an upvote, because it seems like a plausible scenario and I had the same question. I have to say though, it feels a little uncomfortable upvoting a comment about rape.

user

9 months ago

[deleted]

make3

9 months ago

I wonder if we will Jurassic Park a neanderthal one day, that would be interesting (meaning, make a living neanderthal probably by putting the genome in a human cell & getting it to develop into a fetus likely in a human womb, etc). I'm happy I'm not that neanderthal person.

peppertree

9 months ago

Yes. They named him Danny Devito.

ldjkfkdsjnv

9 months ago

The big secret: Different human populations are actually just different hybrid compositions of ancient hominids. All have "Homo sapien" as a common mixin, but the other populations mixed in were way more diverse.

niemandhier

9 months ago

This is technically correct but unfortunately presented in a confusing manner.

Different modern human populations have indeed different trace amounts of genetics of other lines of humans, but it’s „homo sapiens sapiens plus 1-4% homo sapient x“ for all of them.

The Wiki page is a good source of references: https://en.m.wikipedia.org/wiki/Interbreeding_between_archai...

faangguyindia

9 months ago

% of DNA mix do not accurately describe the changes

For example, an African person can have 0.1% European genes and still may look fully blonde with blue eyes and European facial features.

What matters is what that 0.1% is bringing. If those genes are largely not affecting anything at 20% well then why we should care if it's 0.1% or 20%

dmead

9 months ago

There is absolutely no evidence of this. Sounds like something to focus on if you really want to find a rational basis for racism.

ldjkfkdsjnv

9 months ago

There is a ton of evidence of it. Some humans are up to 20-30% neanderthal. Professors just arent screaming it from the rooftops. See the most recent dwarkesh podcast

simonh

9 months ago

I think you’ve got your facts garbled, or the podcast has. Up to about 20% of Neanderthal DNA has survived somewhere dispersed among humans, but some countries and backgrounds have a maximum of 3% per human. The average is about 2% outside Africa.

ldjkfkdsjnv

9 months ago

watch the podcast again, he explicitly calls out:

"but some countries and backgrounds have a maximum of 3% per human. The average is about 2% outside Africa."

as mostly false

astine

9 months ago

I would like to see his sources because that contradicts the most well known studies. There are still a lot of paleoanthropologists who don't think that interbreeding was possible at all and the apparent Neanderthal admixture in modern humans is due to contamination.

https://www.sciencedirect.com/science/article/abs/pii/S10406...

ldjkfkdsjnv

9 months ago

dont have time to find it. he basically says the 2% thing is an antiquated understanding that conflicts with recent ancient dna studies. Go watch the podcast

https://www.youtube.com/watch?v=Uj6skZIxPuI

simonh

9 months ago

I can track down the studies he’s criticising. A Google search doesn’t show up anything refuting those. What are the studies he’s citing?

Tor3

9 months ago

Watched it. He didn't present _any_ sources supporting his claims. There's nothing there.

ldjkfkdsjnv

9 months ago

Publishing a ton of research on this would basically be a career ending move

dmead

9 months ago

Ok, you're almost there. Why would it be career ending?

Tor3

9 months ago

If there's a ton of evidence for this, please provide some citations. I for one have never heard a single scientific claim for individual people having 20-30% Neanderthal DNA. As the sibling comment said, there may be that much Neanderthal DNA spread around in total, but no single individual sapiens has more than a tenth of that.

fsckboy

9 months ago

the article mentions a rare distomolar: (dentistry) A congenital supernumerary (extra) tooth located posterior to the third molar tooth

an extra/supernumerary tooth in another part of the mouth would be called, front to back, a mesiodens or a paramolar

supernumerary teeth may be:

Supplemental (where the tooth has a normal shape for the teeth in that series);

Tuberculate (also called barrel shaped);

Conical (also called peg shaped);

Compound odontoma (multiple small tooth-like forms);

Complex odontoma (a disorganized mass of dental tissue)

(most of that info is from wikipedia, but it did not have the definition of distomolar, had to chase that down in wiktionary)

https://en.wikipedia.org/wiki/Hyperdontia which cites Oxford Handbook of Clinical Dentistry.

user

9 months ago

[deleted]