A cave in Russia

By July 16, 2024Science, Technology

Denisova cave, situated in the foothills of Siberia’s Altai Mountains, is the only site in the world known to have been occupied by both archaic human groups (Neanderthals and Denisovans) at various times, as well as by us ‘modern’ humans. 

New studies show that the cave was occupied by people from at least 200,000 years ago, with stone tools in the deepest deposits suggesting human occupation may have begun as early as 300,000 years ago. Neanderthals visited the site between 200,000 and 100,000 years ago, with a girl of mixed ancestry (‘Denny’), revealing that the two groups of hominins met and interbred around 100,000 years ago, the first direct evidence of interbreeding between two archaic hominin groups (Denisovan father, Neanderthal mother)1

Denisova cave first came to worldwide attention in 2010, with the publication of the genome obtained from the fingerbone of the girl belonging to a group of humans not previously identified in the palaeoanthropological record; the Denisovans. Further revelations followed on the genetic history of Denisovans and Altai Neanderthals, based on analysis of the few and fragmentary hominin remains. Most of the evidence for Neanderthals at Denisova Cave falls within the last interglacial period around 120,000 years ago, when the climate was relatively warm, whereas Denisovans survived through much colder periods, too, before disappearing around 50,000 years ago2.

Unless you live in a similar cave, you will have heard of Neanderthals, Peking Man, Java Man and all the discoveries in west Africa, but may not have heard of the Denisovans, as they are a relatively recent discovery. In addition, the Denisovans are the first ancient hominin species to be revealed by their DNA alone, not by the morphology of their fossils. The girl’s finger bone from which the DNA was extracted has been dated from about 60,000 to 80,000 years ago. While placed in the genus Homo, they have not yet been given a species classification as no physical description is possible3.

More recently, the genome of another Denisovan has been sequenced from a specimen from the same cave. At 200,000 years old, it is the oldest human DNA (by some 80,000 years) to be extracted from a fossil. This DNA is from a male and came from a separate population of Denisovans from the previously analysed girl3.

At the other end of the Denisova age scale, is a woman who held a deer-tooth pendant some 20,000 years ago, and who left her DNA on the ancient artefact. The woman’s DNA was extracted from inside pores of the tooth. Comparing her genetic sequence with other sets of ancient DNA showed that she was a member of our species, Homo sapiens, and had north Eurasian ancestry4.

The ability to obtain this amount of detail from DNA began over 40 years ago. Biochemist Kary Mullis says he was driving to his cabin in Mendocino, California in 1983 when suddenly, like a bolt of lightning, he came up with a way to pinpoint a particular stretch of DNA and synthesise an enormous number of copies. For this, Mullis won the 1993 Nobel Prize in Chemistry for inventing polymerase chain reaction, or PCR. Before PCR, studying DNA was difficult. Isolating exactly the right small snippet of DNA to study was extremely difficult. Even if it was possible to isolate a section of interest, the amount of material was often so minuscule that there just wasn’t much available to study5. PCR changed all that and allows the DNA from a couple of cells trapped in the finger bone of a girl who died many thousands of years ago, to be copied millions of times and thereby analysed.

Sources

  1. https://www.theguardian.com/science/2018/nov/24/denisovan-neanderthal-hybrid-denny-dna-finder-project
  2. https://www.arch.ox.ac.uk/denisova-cave
  3. https://www.science.org/content/article/most-ancient-human-genome-yet-has-been-sequenced-and-it-s-denisovan
  4. https://www.nature.com/articles/d41586-023-01482-3
  5. https://www.nationalgeographic.com/science/article/the-eccentric-scientist-behind-the-gold-standard-covid-19-pcr-test

9 Comments

  • James Faulkner says:

    Yes. Denisovans DNA is extant in East Asians in the same way Neanderthal dna is in euros. Also, apparently in aboriginals.
    On that note, I’ve been painting wargaming miniatures of “Denisovans” , at least that’s how they are sold, but are more or less usable for frontiers wars in Australia or tribal conflict scenarios.
    Not many seem to know about these other human species, nor understand how they may have interacted. Part of the problem might be that’s it’s hard to conceive primal conditions from the comfort of the modern world, the other is the closed and conservative nature of the explanation of human evolution.
    Yeah, evidence seems to pull our time back to a smaller and smaller period, and extends the other hominid species a little, but my feeling is that the story is well and truly misunderstood.
    I’ve no evidence, and I’m not really chasing any, but I’m it NOT about to go down the von daniken (sic) route, I just suspect that we modern humies, including many eminent researchers just cannot conceive of an ancient ecosystem that was primarily primates. Too many children’s books about elephants and zebras and that all monkeys live in Africa and all the Disney lies have not helped. Limited imaginations.
    Anyway, I’ve been staying back and watching the conservatives try desperately to keep the history of humanity within arguably biblical time frames, or at least the shortest possible, and to keep the basic knowledge of all primal human groups in a sort of mythological state of woo. (“Who could have thought they could make these tools so sharp” etc etc etc when it’s like duh)

    All the best, and yay for dna

    James

    • admin says:

      James,
      It is fascinating stuff. I read Pääbo’s book ‘Neandethal Man’ which was the first ‘fossil human’ genome to be sequenced, and was engrossed by the story and made me slightly envious, as my game is trying to make sense of long dead arthropods; less glamorous but still enjoyable. You have hit on one of the problems that this discovery of assorted human ‘species’ What the hell is a species? Nobody seems to know. There are lots of definitions and the one most referred to in popular science from years ago is that two animals are of different species if they cannot produce fertile offspring. The mule was the example most often given when I started in this game, and that definition was called ‘the biological definition’. However, while that might roughly work in the modern world (ring species and fertile hybrids are not particularly common), in the fourth dimension, it doesn’t work, because we do not have knowledge of the parent/child relationship. Years ago, while thinking about ‘species’, I wrote a piece here entitled ‘Did Linnaeus get it wrong?’ and did a thought experiment which went like this. If I stood on the northern tip of the ACT (where I live) and my parent was a metre away to the right, and their parent a metre away from their right and so on all around the ACT, the person standing at my left would be about 300,000 generations ago and would not only be classified as a different species, but also a different genus! https://blotreport.com/2017/06/10/linnaeus-get-wrong/

      One of the items to which I refer in the article, noted that Denisovan DNA is more prevalent in Han Chinese, Papuans and indigenous Australians. Fascinating stuff.

      Not long before I wrote this I read an article on Nature about the geneticist who cause the release of Catherine Folbigg, the woman wrongly convicted of murdering three of her four children. She sequenced Folbigg’s genome and found a rare mutation which was apparently the cause of the deaths. https://www.nature.com/articles/d41586-024-02324-6

      I am constantly astonished by by the stupidity of conservatives who, as you say, are completely lacking in imagination and knowledge. Not only that, but where we have the knowledge, they refuse to acknowledge it. It infuriates me.

      • James Faulkner says:

        Note that’s a point I hadn’t considered: how to define a species, or exactly what do we mean?
        One of the problems in “science” is the apparent discrepancy between quanta (not in the physics sense, in the sense of individual measurable units) and continuum. In some cases we can see how the continuum may be broken up into convenient quanta, in others it’s just not so clear. Biology seems to be one of those continuum deals in which things blend into each other in an holistic interconnectedness (Dirk Gently). I mean, according to Flannery, and I’m inclined to agree, what is a fish?
        As for humans, well, right now we are in another of those strange idealistic moments where the biological and evolutionary origin of humans is being conveniently ignored in order to justify whatever social or religious bee they’ve got in their bonnet, and fuck the rest of the biosphere. We are behaving as if we aren’t the beasts we arose from, and all that animal behaviour was shed thousands of years ago and we instantly became civilised. Pffft. We are behaving as if we are the superior, ultimate end all and be all, as if there’s no where else to go along the evolutionary path. We are blinded by our own cleverness from our origins and how those origins affect behaviour, society, culture, etc etc etc. I’d blame it on religion, but I know it’s not just that. It’s quite simply human arrogance.
        I can’t really cite sources for my rants.

        As for the Denisovans that began all this, I am hoping that we can find more supporting evidence so that the concept of many early human species rather than the handful they care to admit to. It’s interesting. I’m in Armidale, studied at une, and had a few friends who’d studied archeology with that fellow who found Floriensis. (In the nineties). So I’m well aware of others, famous as they are, that don’t seem to have a place among the standard human story, and have been sidelined as curiosities and unsuccessful evolutionary paths. Maybe we uptight humans may yet get over ourselves, one can only hope.

        All the best
        James

        • admin says:

          James,
          A fair proportion of science is the classification of things; everything from fundamental particles to cosmological bodies. In many cases the classification comes up against something which is a continuum, and this causes enormous problems and arguments. When I posted that ‘Did Linnaeus get it wrong’ on a palaeontological site, many people said nothing, but some went ballistic. I was accused of not understanding what Linnaeus was on about which is just silly. Many people get a bit precious about their science and cannot come to grips with people wanting to change things or, in my case, to point out some shortcomings of the present ‘understanding’. I suppose it is because many people hate change. On another topic, I do believe that human arrogance is based in religion. Religion tells people they are special and better than all other animals as well as members of all other religions. Its decline is a sign of genuine progress.

  • James Faulkner says:

    Agreed. Time for the gods to sleep and the humans to wake up.

    • admin says:

      James,
      What gives me the jimmies is that this change which we can all see needs to happen, comes up against people who are concerned their privilege is at risk, so they will fight it tooth and nail. As a consequence, it takes an inordinate amount of time for that change to happen.

      • James Faulkner says:

        Yes, scary isn’t it? If I try to call out the self interested, either they or their victims will gather the pitchforks and I’ll again be chase out. I’m rather sick of having real life discussions about this that end in me being savaged in one way or another by small minded and ignorant. I’m really not sure how this plays out in other less selfish cultures, but here in the American colony of what used to be Australia they really hate it. Maybe there’s a scrap of whatever passed as culture we managed to create before the septics came and bought it out from under us again, but even that’s got to be fairly rotten. Between the self interest of enlightenment thinking and the commitment to profit that really is the backbone of our so called civilisation, Australia really is little more than a clearing house for the commercially irresponsible, and the attitudes of our people really show it.
        Perhaps I’ve had a few too many bad encounters with stupid Australians.

        Back to the Denisovans. I know pretty much bugger all about the process of carbon dating. When this is done, I assume (perhaps incorrectly) that the results will give a large gap in time between possible ages rather than a more precise measurement. For example, between five and ten thousand years rather than exactly seven thousand. Assuming the range, do the writers of the papers use the earliest date, the latest or go for a medium number, or actually be content to work within the vagaries of the range? Do they need to state precise numbers just because there are idiot people can’t understand a range? Or does this all get confused by those so called science commentaries that have to dumb stuff down for the monkeys who want to look clever?

        I really don’t know.

        • admin says:

          James,
          With regard to radiometric dating (there are several sorts) what usually happens is that there are several samples dated, and the statistical mean is the date used and most commonly it is given with a +/- of the standard deviation or sometimes two times the standard deviation. In stuff I have been involved with, this is expressed like 250 +/- 0.15 million years. This means that the Uranium-Lead date of a particular group of zircons is basically given as 250.15 – 249.85 million years. Dating with this precision is only a recent development. Previously it would have been 250 +/- 3.0 million years. Carbon dating is only used to date organic material less than about 50,000 years as the half life of Carbon 14 is relatively short. I wrote a piece about Carbon dating some years ago, in response to a wilfully ignorant creationist. It is here: https://blotreport.com/2018/08/16/radioactivity-and-ignorant-creationists-1/

          • James Faulkner says:

            Well, well, well. Thankyou. I did not know that about carbon being generated in atmosphere in that way. It explains well why we use C to date things in the short term. Of course, thinking about it for less than a second, it makes perfect sense. High energy high atmosphere activity….
            Still, the dating method extends well beyond the small window given by the godbotherers. It’s no wonder they can’t conceive that carbon dating won’t give us the age of the universe when their tiny minds can’t stretch past five thousand years. Creationists are a mystery, unlike the universe. The universe will make sense, they never will. Dont get me started.
            Anyway, thanks for the explanation, I’d overlooked the use of +/- error. Of course that how they’d express it, they are scientists not journalists. My bad. I was never more than a casual scientist, but I should have remembered. I did do stats at uni, way back in the early nineties, and the expression of uncertainty always impressed me with its honesty.
            All the best
            James

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