High-altitude cave used by Tibetan Buddhists yields a Denisovan fossil | Hacker News Reader

High-altitude cave used by Tibetan Buddhists yields a Denisovan fossil

arstechnica.com

147 pointsnamanyayg27 comments

This is really interesting for another reason (which is kind of buried at the end of this article).

A variant of the gene EPAS1, which occurs at low frequencies in east asia, and relatively high frequencies on the Tibetan plateau seems to be identical to the variant found in Denisovans, implying that Homo Sapiens got it by interbreeding with Denisovans, and natural selection on the Tibetan Plateau maintained high frequencies of this gene in Tibetans specifically since it confers some resistance to high altitude hypoxia.

This is a somewhat rare example of both gene introgression across species (or subspecies?) and positive natural selection, and on top of that its happening in humans!

The article didn't mention Sherpas. But I assume they have the same gene?

I should note that its only something like 1/3rd of Tibetans who have this variant, and something like 1/200 Han Chinese, Vietnamese, Laotians, etc who have this variant (If you go back tens of thousands of years, basically everyone is related to everyone else, so the allele frequencies here are truly implied to be driven by natural selection rather than just simple descent). I vaguely recall that Nepalese have a fairly high frequency of these variant but I'm not sure how high. Would need to dig up the paper

Speciation of archaic humans is an attempt at applying discrete categorization to continuous phenomena. It's like looking at a rainbow and trying to figure out where red ends and orange begins. Also interesting is Homo Longi, which can be argued to be Denisovan, or maybe not, depending on where you want to draw the lines on the raindow: https://en.wikipedia.org/wiki/Homo_longi

All speciation is this. It’s muddy and not all that useful for the intermediate stages between one species and two.

I’ve gotten the impression from several practicing archaeologists that the biggest reason they haven’t unified a bunch of the Homo species is that no one can quite agree on how to do it and there’s so much inertia in the field. Between ample evidence of interbreeding, the growing evidence that our genetic differences weren’t that significant compared to modern variability in the human gene pool, and a reevaluation of morphological differences it’s getting harder and harder to justify keeping them separate.

As a sibling comment mentions, this is true for pretty much all animals. It's a well-known, old problem. Darwin even mentions it in the Origin of Species and says that "species" is really just a term of convenience applied somewhat arbitrarily according to the different tastes of different naturalists.

Now we understand even better that, like GP said, there are no discrete groupings we can label as a species. It's a useful abstraction at a 5000ft level but it breaks down when you zoom in.

The lines are arbitrary, but it may still be useful to draw them for some applications.

It’s a rainbow all the way back to the first tetrapod (and beyond). But clearly we are not fish, so somewhere in that spectrum there is a useful distinction to be made, a line to be drawn. Of course, the closer you get to finding that line, the faster it vanishes. It’s equally futile to say that we are indistinct from fish because there is no clear and decisive separator.

Yup, same with drawing lines on a rainbow.

The concept (and definition) of red, orange, etc. is important and useful. A great many things would be impossible without it frankly. [https://en.m.wikipedia.org/wiki/Spectroscopy]

Applying it in real life in some situations sometimes has a fractal like quality. Like measuring a shoreline.

There are definitely red and orange colors though…

Technically, are humans that use the internet a different species than humans that don’t, since they don’t interbreed?

Underrated comment.

The funny thing is Denisovans and Neanderthals actually interbred both amongst each other and with Homo Sapiens making them all the same species: Humans.

Are there still humans that don’t use the internet?

Don't and can't are two different things.

Furthermore, Great Danes and Chihuahuas are of the same species. And while there may be no direct genetic mixing between the two ends of that spectrum, you can have Chihuahua - Beagle - Labrador - Great Dane mixes (with the '-' being a mix) ... and they're all the same species.

That cave location looks like such a prime piece of real-estate for a Paleolithic hunter group.

Imagine 3-5,000 generations of Denisovans using that cave. It boggles the mind.

If Denisovan people were present only 30,000 years ago in Asia, wouldn't at least some stories have survived, perhaps in the form of legends passed down the generations? Would be interesting to know if there's any candidates amongst the local population.

If there are then Crecganford [1] will have probably covered it and followed the evolution of the story across the world - a real treasure trove of a channel (I advise using closed-captions as he often hurries through words).

[1] https://www.youtube.com/@Crecganford

That's a very long time for anything to survive. Like, notably, their bones.

But we do have evidence of some traditions from ~12kya, so it's possible some shadows of the idea are left. It can be thought that the folklore tradition of crypto-peoples (the elves, dwarves, green men, etc) may contain some echo of other hominids, though any specific connection or detail is unlikely.

It’s not necessarily obvious that “normal” humans would have recognized them as a different species. Might have just seen them as a different tribe/race with different facial/etc. features

Well, I think that that's obvious , no? It's not like they had any idea about evolution and speciation yet.

Altitude= not connected to the ground.

Elevation= connected to the ground.

High-altitude is a commonly used pair of words to refer to mountain locations.

I challenge you to find a dictionary that doesn't include "elevation above sea level" in one of the definitions for altitude.

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

Cool, but not in the English I learned.

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