Prehistoric Humans May Have Interbred With Two Separate “Superarchaic” Species (www.iflscience.com)

submitted 6 days ago by monica_b1998@lemmy.world to c/science@mander.xyz

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[-] Gsus4@mander.xyz 8 points 6 days ago* (last edited 6 days ago)

actual paper: https://www.biorxiv.org/content/10.64898/2026.03.22.713509v1?ct

actual title: Human Ancestors Interbred with Two Distinct Populations of Distant Relatives

abstract:

Ancient DNA has shown that a distantly-related “superarchaic” population interbred first with the ancestors of Neanderthals and Denisovans and later with Denisovans themselves. Other work has shown that a superarchaic population interbred with the African ancestors of all modern humans. But it is not yet clear whether these events involved the same superarchaic population. Here, we use the distribution of derived alleles among populations to evaluate hypotheses about superarchaics and their relationship to other hominins of the Pleistocene and Holocene. We find evidence for at least two distinct superarchaic populations. The one contributing to archaic Eurasian populations (Denisovans and Neanderthal-Denisovan ancestors) diverged earlier from the human lineage than did the one contributing to early moderns in Africa. These findings reveal previously unrecognized structure among hominin populations of the Pleistocene.

[-] CanadaPlus@lemmy.sdf.org 4 points 6 days ago* (last edited 5 days ago)

It's worth a read just for the diagrams of possible timelines. Apparently there was at least one earlier wave of Homo Sapiens ancestors going to Europe, too, labeled gamma, which would have just been absorbed by the Neanderthals.

The Eurasian superarchaics would themselves have left Africa around 2 million years ago, with the very first Homo Erectus or Habilis migrants into the larger world.

[+] givesomefucks@lemmy.world -9 points 6 days ago

If two species can bang and produce fertile offspring...

It's one species.

For whatever fucking reason, people really want to chop up human evolution into different species.

Just like racists saying modern humans are different species, when clearly we're not.

[-] lvxferre@mander.xyz 12 points 6 days ago

If two species can bang and produce fertile offspring… // It’s one species.

I got another violation of this principle at home.
\

The plant in the photo is a Capsicum annuum (bell pepper) x C. baccatum (ají / dedo-de-moça pepper) hybrid. It's fertile; in fact the seeds from the fruit in the pic just sprouted. Following the principle you mentioned, and that I learnt as the definition of species, both parents should belong to the same species.

This shows biologists are using more criteria than just viable offspring to define species. But I don't know which ones. (It also hints the matter is not racism, as it applies even to plants.)

[-] DragonTypeWyvern@midwest.social 3 points 2 days ago* (last edited 2 days ago)

Ask 10 biologists to define species and you'll get 12 answers, but while a species must be able to have fertile offspring it's always linked to other traits like reproductive isolation from other groups and even more traits after that but it's all disputed and too complicated for a forum comment.

So in the example of hominin interbreeding they'd have been separated by geography prior to the migrations and be different species as a result of that and other factors.

For example, given another ten thousand years of reproductive isolation Old and New World homo sapiens might have differentiated, or maybe not. It all depends on population sizes and whether there's enough adaptative pressure (aka mass dying)

There's a movement now to try and define species based on genetic similarity but I think that's pretty fucking silly when a single mutation could, for example, make the species sterile. You're just never going to able to define it in a mathematically useful way.

[-] Mandarbmax@lemmy.world 8 points 6 days ago

Eh, for the most part yes but really "species" is a social construct and sometimes two members of the same species can't interbreed at all ; see ring species for example, where for a very brief example, a central population of salamanders can interbreed with northern and southern populations but the northern and southern populations can't interbreed with each other, and if the northern population extends south west and the southern population extends north west they can overlap but still not interbreed but also still exchange genes by both breeding with the central population, super funky stuff!

But then you can also have clearly different species that mostly can't produce viable offspring but sometimes can; rarely mule can produce offspring for example.

There are also different species that can regularly and reliably produce viable offspring such as various species of milksnake and kingsnake (see particularly the imperial pueblan milksnake hybrid of pueblan milksnakes and Californian king snakes), between horses and Przewalski's horse (which even have different numbers of chromosomes), between American bison and domestic cattle, and camel hybrids (who readily and regularly backcross to produce 75% dromedaries or 75% bactrians).

Biology is so messy and interesting! I find it fascinating. I don't mean to undermine your point about racists calling different modern humans different species being a bad thing; it might be an interesting biological discussion but racists poison the well so to speak. The utility of camel hybrids and backcrosses would be evidence enough to show a reasonable person why it wouldn't be a bad thing. Alas, racists are dumb.

[+] givesomefucks@lemmy.world -7 points 6 days ago* (last edited 6 days ago)

but really “species” is a social construct

Unless you draw a hard line, which is what biologists did...

super funky stuff!

Super common stuff... Nature just weird bro.

There are also different species that can regularly and reliably produce viable offspring

Then they're not truly different species...

Like, I already linked and quoted the part from Brittanica about how we don't have to just go off morphology to differentiate like we did when people decided those were different species.

I really don't understand the confusion here.

Every argument for why that shouldn't be the sole line, circles back to "that's not how we always did it".

Do you understand that and are just arguing for the consistency of it despite it not logically making sense?

Cuz that's just an opinion, I'm not gonna be able to change that

Logic tho, that's just what it is. And that's kind of the hocky pocky of science.

[-] Mandarbmax@lemmy.world 9 points 6 days ago

I say this with respect: your response looks as though you did not fully consider the impact of ring species as I had mentioned.

Please take a closer look and get back to me.

[-] DragonTypeWyvern@midwest.social 3 points 2 days ago

You can just say they have as much of a middle school definition of species as the racists, it's true even if it's rude

[-] Mandarbmax@lemmy.world 3 points 1 day ago

I was hoping if I was polite he would explain more of his insane "one animal, two species" point of view. Alas, I think he bumped his head on the logical contradiction and left.

[-] givesomefucks@lemmy.world -5 points 6 days ago

In biology, a ring species is a connected series of neighbouring populations, each of which interbreeds with closely sited related populations, but for which there exist at least two end populations in the series which are too distantly related to interbreed, though there is a potential gene flow between linked neighbouring populations.[1]

https://en.wikipedia.org/wiki/Ring_species

End points have differentiated enough to speciate, what's in between is a "sub-species" of both.

I don't understand how you think that's different then the normal process, it's literally the normal process when there isn't a clear geographical divide...

[-] Mandarbmax@lemmy.world 6 points 6 days ago

Your position is that something can be two species at once? I suppose that is one way to solve the problem of where to draw the line for speciation!

Completely out of line with the perspective of modern biology but fascinating and internally coherent none the less! It will take me years to fully digest this perspective. Thank you.

Saying that something can be two species at once is none the less not a compelling argument against the concept of a species being a social construct, as your perspective clashes with others'.

[-] givesomefucks@lemmy.world -5 points 6 days ago

Your position is that something can be two species at once?

No, I'm saying two species can share a mutual subspecies...

End points have differentiated enough to speciate, what’s in between is a “sub-species” of both

I'm not sure if it makes more sense one way or the other, but obviously that's a fundamental point you'd need to get before we move further.

But you keep down voting and being weirdly argumentative about this.

You do realize I gain absolutely nothing from helping you understand, right?

If you act like this, most people are just going to stop trying to teach you stuff

[-] Mandarbmax@lemmy.world 6 points 6 days ago

So what species is the sub species then under your framework?

[-] dewritoninja@pawb.social 5 points 6 days ago* (last edited 6 days ago)

That would make polar bears and grizzly bears the same species of bear

[-] Gsus4@mander.xyz 0 points 6 days ago* (last edited 6 days ago)

Where do new species come from over time, then? You seem to be saying that there is a time when they are all variants of the same species...and then...bam! Different species.

PS: https://en.wikipedia.org/wiki/Hybrid_speciation

PPS: eg https://mallet.oeb.harvard.edu/publications/hybridization-invasion-genome

[-] givesomefucks@lemmy.world -1 points 6 days ago

Where do new species come from over time, then

A population diverging to the point where they can no longer consistently produce viable offspring...

You seem to be saying

No, you're just making assumptions after not understanding something and down oting it.

Why do you think people would spend time teaching things to you when you act like this?

[-] CanadaPlus@lemmy.sdf.org 3 points 6 days ago* (last edited 6 days ago)

That's the one reasonably well-defined definition, anyway.

Neanderthals and humans produced often/usually sterile offspring, though.

[-] givesomefucks@lemmy.world -2 points 6 days ago* (last edited 6 days ago)

Neanderthals and humans produced often/usually sterile offspring, though.

I never heard that, and I can't even think of a way that evidence could show that...

We know that for whatever reason there's less neaderthal on the X chromosome, but that doesn't have anything to do with sterility of offspring at a high frequency.

It most likely was just that any mutation that did make it over, was outcompeted. Which comes back to the prevailing theory that "modern" humans main advantage was reproducing like bunnies, and that advantage was carried on our X chromosome.

That would mean the neanderthal DNA that was passed down and still around, came over from the crossing of male neanderthals with female humans to male sons. Which (going off memory) we do have evidence to support.

Those "hybrids" would have children with "human" X's even if they were daughters, but be introducing neanderthal DNA back into a "double human X" mother, ensuring her daughter still had the reproductive advantages over a neanderthal mother still, but retaining neanderthal genes adaptive to the northern climate.

Shake and bake a couple generations, you get white people.

But at no point does it mean any "hybrid" was sterile, just that a thousand years later they didn't have direct living descendants, an incredibly common thing especially back them.

Edit:

This already happened with cro-magnons:

https://en.wikipedia.org/wiki/Cro-Magnon

Because we only had morphology to go off of, they were labelled a separate species.

However that was largely due to their harder lifestyle than genetics and with DNA testing they're now recognized as a "sub species" which is why later waves of "modern" humans reabsorbed them into the gene pool so quickly, likely along with some neanderthal DNA as icing.

All I'm saying. Is that eventually the other "archaics" will get the same recognition as "siblings" on the family tree and not "cousins".

It's just human variation is far wider than popular opinion or present examples.

[-] CanadaPlus@lemmy.sdf.org 3 points 5 days ago* (last edited 5 days ago)

In other species that intermix like that, you see stretches of DNA where all admixture is excluded, because it's instantly selected out. In humans, such a stretch exists, and has to do with sex determination, which is a pretty much a smoking gun. I'm finding stuff about the Y chromosome, but I thought there was something on the X chromosome to do with testicle development as well.

Obviously, female hybrids were fertile at least some of the time, since there is admixture. But, it's possible every half-and-half male hybrid ever ended up sterile, and later generations would probably have had higher rates of sterility.

The general idea that humans are irrationally obsessed with categories and tribes holds, but this doesn't seem like a clear-cut example.

but retaining neanderthal genes adaptive to the northern climate.

Shake and bake a couple generations, you get white people.

Anyone outside of Africa has similar-ish admixture; skin colour has little to do with it. European hunter-gathers at the end of the ice age were what we'd consider black, and they were replaced by Middle Eastern looking and originating agriculturalists. The light skin colour is from Eurasian steppe nomads that rode in on the first horses in the bronze age. Other unrelated groups, like from the Caucuses area or pre-modern Japan, also have/had light skin.

[-] givesomefucks@lemmy.world -3 points 5 days ago

I'm sorry, there's just so many incorrect things you just gishgalloped that were never gonna get thru this.

I can't explain anything if every time I try you being up 5 more things you need explained.

[-] CanadaPlus@lemmy.sdf.org 3 points 5 days ago* (last edited 4 days ago)

Here, I won't add anything, I'll just cited what I've brought up:

The Neanderthal stuff is recent research and still kind of in flux, so you could object that there might be another interpretation somehow. The bit about everyone outside of Africa having admixture is here, and it actually mentions that east Asians have the highest proportion.

On the origin of white people, here's the steppe herder component and here's the bit about them having horses. This is the Middle Eastern agriculturalist part and these are the original hunter-gatherer inhabitants of western Europe, specifically the section on them likely being black and blue-eyed.

This is a photo of historical Ainu in Japan which gives a sense of why I'd compare them in appearance to Europeans, as some of the Europeans themselves did. There isn't actually a close relation:

[-] Gsus4@mander.xyz 3 points 6 days ago* (last edited 6 days ago)

Ok: dogs and wolves (and coyotes) Different species, can interbreed. Genetics is complicated. Definition of species as a human concept is complicated. Speciation is complicated, fuzzy, can happen on and off depending on the ~~mutation~~ involved genes and there can remain bridge individuals that are variants who can breed between separate species. 😬

[-] givesomefucks@lemmy.world -4 points 6 days ago* (last edited 6 days ago)

Buddy...

It's the same thing.

If humans interbred and produced fertile offspring with "superarchiac" hominds, then they were the same species the whole time and never truly differentiated.

If modern dogs can interbreed and produced fertile offspring with wolves, then they were the same species the whole time and never truly differentiated.

I hope I taught you something

You don't even know the scientific definition of "species"...

species, in biology, classification comprising related organisms that share common characteristics and are capable of interbreeding.

https://www.britannica.com/science/species-taxon

Quick edit:

You added a link to hybrid speciazation...

Where two different groups who have differentiated from a parent species in similar enough ways that they can reliably produce fertile offspring...

Meaning they are the same species and not two separate ones, their populations just didn't overlap before.

Overtime they may differentiate

Like, all this is relatively basic, but if you keep asking questions with this attitude I'm not likely to keep explaining shit

[-] Gsus4@mander.xyz 4 points 6 days ago

Ok, you must be trolling. You are building your whole argument on a reductive definition of species that predates genetics.

[-] givesomefucks@lemmy.world -4 points 6 days ago* (last edited 6 days ago)

reductive definition of species that predates genetics.

Literally the opposite...

I'm going to quote a lot you probably won't read from the above link, but at the bottom I'll bold the bit that says you're operated on flawed historical assumptions that predate DNA. Stuff that used morphology (what something looks like) because that's all we could do

First off, you're not understanding what a subspecies is, so quoting that bit:

Subspecies are groups at the first stage of speciation; individuals of different subspecies sometimes interbreed, but they produce many sterile male offspring. At the second stage are incipient species, or semispecies; individuals of these groups rarely interbreed, and all their male offspring are sterile. Natural selection separates incipient species into sibling species, which do not mate at all but which in morphology, or structure and form, are nearly indistinguishable. Sibling species then evolve into morphologically (and taxonomically) different species. Because it is often difficult to distinguish between subspecies and stable species, another criterion has been developed that involves a historical, or phylogenetic, dimension. In this form, a species is separated from another when there is a parental pattern of ancestry and descent.

Fourteen species of Galapagos finches that evolved from a common ancestor. The different shapes of their bills, suited to different diets and habitats, show the process of adaptive radiation.

Speciation may occur in many ways. A population may become geographically separated from the rest of its species and never be rejoined. Through the process of adaptive radiation, this population might evolve independently into a new species, changing to fit particular ecological niches in the new environment and never requiring natural selection to complete its reproductive isolation from the parent species. Within the new environment, populations of the new species might then radiate into species themselves. A famous example of adaptive radiation is that of the Galapagos finches.

But here's the part about genetic you got backwards:

There are many hypotheses about how speciation starts, and they differ mainly in the role of geographic isolation and the origin of reproductive isolation (the prevention of two populations or more from interbreeding with one another).

The evidence for speciation formerly was found in the fossil record by tracing successive changes in the morphology of organisms. Genetic studies now show that morphological change does not always accompany speciation, as many apparently identical groups are, in fact, reproductively isolated.

Like, it's almost impressive that you managed to be so convinced of the opposite of the scientific consensus in every possible way...

Where are you getting your information?

TikTok?

this post was submitted on 29 Mar 2026

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