Early Humans and interbreeding

By Legal Eagle

Last night my husband and I were watching the first episode of A History of Ancient Britain by Neil Oliver. I love archaeology. For a large portion of my childhood and beyond, I wanted to be an archaeologist. I’m fascinated by glimpses of people in the past.

One of the things I always feel sad about is the fact that there were a number of other human species (hominids), but they died out. I think it would be awesome if we were still co-existing with other human species. The behavioural differences and similarities would be fascinating. But it seems that the genes of at least two of those groups live on in us. LP has a post today which details how evidence has emerged that the humans who moved out of Africa interbred with Neanderthal and Denisovan populations, which gave the humans resistance to diseases which the Neanderthal and Denisovan people had already encountered. Please go have a read.

Poor Neanderthals get a very bad press. Since they were discovered, their name is a by-word for brutish savagery. However, the evidence suggests the opposite. First, they were capable of speech, as the Neanderthal hyoid bone was indistinguishable from ours, they had a hypoglossal canal, and they had a gene (FOXP2) which is essential for human language capacity. Thus, it is has been hypothesised that they had speech. They also seem to have had burial rituals, as there is evidence they buried their dead with flowers and other items (although some have contested the presence of flowers as being random chance). They used tools and fire. They may have used ochre make up, and possibly made jewellery and pendants. There is also evidence of Neanderthal compassion (via skeletons of disabled or unwell individuals who could only have survived with care from family members) and Neanderthal interpersonal violence (via a skeleton of an individual with a cranial fracture which could only have occurred as a result of another person hitting him – although he survived and the wound healed). On the downside, there is also some evidence of Neanderthal cannibalism (flesh being cut from bones by stone knives), although whether it was really cannibalism or not is still hotly debated.

Of personal relevance to me is the hypothesis that the gene for red hair, pale skin and freckles originated with Neanderthals. This means that if the hypothesis is correct, my husband and I must have Neanderthal genes, and Eaglet No. 1 indubitably does (her hair is a flaming red, and she has creamy white skin and freckles). If I do have Neanderthal genes, I’m rather proud. It means that another human species lives on in me.

Update: Wombo at LP says the mutation for red hair and freckles in Neanderthals was different to the one in humans. Damn.

17 Comments

  1. kvd
    Posted June 26, 2011 at 3:24 pm | Permalink

    Well, here was I becoming relaxed about the proposition that we share 70% of our genes with chimpanzees, and along comes Eaglet #1 proclaiming a 1-4% brotherhood (sisterhood) with English Football fans and Collingwood supporters; and just where does that leave the amoebas and flagellates – the Swans and English cricketers?

    Mind you, I do have a deep feeling of brother/sister -hood with orangutans, and they do seem to have a lovely red undertone.

  2. Posted June 26, 2011 at 4:56 pm | Permalink

    [email protected]: Hah!!! A speciatiion effect creating Homo collingwoodensis officially without possibility of interbreeding is a nice thought.

    Typo in the post you might line fixing: Homonims? HomoniDs are Homo, including sapiens, floriensis, neanderthalis and erectus. Hominids are a subset of Hominins, which includes not only Homo but Pan and Gorilla. Hominids and Hominins are near homonyms, however. Of course, a stuttering taxonomist has continuing problems between hominidae and homininidae. I’m a fan of hominin rather than human rights – and the lack of distinction might be useful for those wanting to prevent mistreatment of H collingwoodensis – even if relabelled Trog collingwoodensis, they’d still be covered by hominin rights.

    The light skin of Northern Europeans was probably an adaptation to allow better Vitamin D production in a cold climate where it was a choice of rickets or freezing to death. There’s a similar reason for lactose tolerance as adults in caucasians, but this would only have had effect after taming cows, sheep or reindeer.

    As a kid, reading of the softness of neanderthals (not just in death – the bones also showing injuries demanding significant periods of incapacity and survival requiring long periods of care by others in the tribe), I caused grief to a dog-collar by asking questions about souls in humans, if existing, then existing in H.neanderthalensis, and if them, present in H erectus and chimps. Did Jesus die to save the soul of Cheetah the friend of Tarzan?

    As to kinship, I feel less with the orangs, which don’t live in tribes like chimps and gorillas. It’s the chimps who share the best and worst of our psychological makeup, the greatest cultural differences between tribes, and provide the greatest insight into the evolution of (and possibly devolution from) altruism.

  3. kvd
    Posted June 26, 2011 at 5:29 pm | Permalink

    Orangs are sad and solitary; I feel more at one with them than chimps; they display a reserve, I imagine, gained from hard experience .

    [email protected] I thought Homonims was a clever reference to Swift, but never mind. More importantly, how do you explain anus Africaans – aka Kevin Pieterson?

  4. Posted June 26, 2011 at 6:21 pm | Permalink

    [email protected] : explain Anus africaans? Privilege. See the link to my post (and follow bouncing balls to original papers) on single adoptive chimp dads in the Tai chimp tribe, which has a /really/ tough time with predators and disease, and shows great costly altruism, much greater than more privileged hominin groups. When life is precarious, the “there but for the grace of god go i” notion is driven home, compassion and altruism follow.

    The neanderthals had a hard life, altruism essential to survival, even if only delayed reciprocal altruism. The development of altruism among us apes, and in other animals, has always fascinated me, and I wasn’t /too/ surprised when a magpie family would offer food to me and my family – although this did widen my sense of kinship with non-mammals.

    As to the question of intentional, not instinctive altruism in other species near and far, it’s also relates to the concept of sin. It’s pretty clear some chimps sin – the worst example being a high-ranking female who played mind games by killing and eating the baby of a competitor, and the fake peace offering of the baby’s flesh to the mother (who naturally rejected it). That is pure evil, and the offending sociopathic chimp surely KNEW it.

  5. kvd
    Posted June 27, 2011 at 5:51 am | Permalink

    Thanks Dave. Your own and the linked articles are very interesting reading. Dunno that I like the thought of seeing study subjects lost to anthrax and ebola tho’.

  6. conrad
    Posted June 27, 2011 at 12:31 pm | Permalink

    “they were capable of speech,”

    Just having a FOXP2 gene doesn’t mean they had speech (you are not going to get Mr Ed if you implant it in a horse), and you can ask someone who is deaf about the necessity of having a vocal tract.

  7. Posted June 27, 2011 at 1:03 pm | Permalink

    [email protected]: Yes, it must be really tough on the researchers, especially as the Tai are obviously easy to develop affection, and even admiration for. It must be even worse than for our small mammal biologist (she was 5 foot nothing in heels, studied things like numbats, so was a small mammal biologist in every way) who came into my lab one day after bushfires had ravaged the otways, holding the charred and twisted traps she’d put out a few days earlier, tears streaming down her face. Her ruined thesis wasn’t the cause of the tears… And her study wasn’t as long as the Tai study, she didn’t record actions that imply deep personalities and emotions, just physical stuff.

    Glad I never had to deal with that kind of thing.

  8. Posted June 27, 2011 at 5:17 pm | Permalink

    Was it a T V program; if so which one?

  9. Posted June 27, 2011 at 5:24 pm | Permalink

    I suppose Tasmanians have their own peculier ancestry.
    Is there any truth that Tasmanians had their own coinage without the tail which enabled them to cheat at ‘Two Up’.

  10. conrad
    Posted June 27, 2011 at 6:57 pm | Permalink

    “I guess they had a number of a preconditions for speech”

    It beats me what the preconditions are (and that’s not because I’m ignorant). In addition, even if FOXP2 is necessary in humans, that doesn’t mean it is necessary in everything that could potentially speak. You can teach birds to deal with recursive structure and categorization (two important things in language) if you try hard, for example, but they don’t have FOXP2. If I had bird with a brain the size of human, who knows they’d be doing (and too bad the bird which I think has the biggest brain and doesn’t presumably waste lots processing power by having to fly is pretty much done for).

    I’m not saying here that now-extinct primates couldn’t speak to each other incidentally, it’s just that if they could in some complicated way, you’d probably want very good evidence for it.

  11. conrad
    Posted June 28, 2011 at 1:22 am | Permalink

    “What kind of evidence would you want, Conrad?”

    First of all I don’t think that you need to worry about having a larnyx and so on — language is basically modality universal, so if they could move their arms, open and close their hands and so on, I don’t see why they couldn’t have language ( even whistling would work, and there are even studies on this). We just think language = speech because that’s what most humans do. But it isn’t necessary. If you want a crazy example, then there are some squid out there that appear to communicate via changing their skin color, which they can do in milliseconds (try looking for them on youtube — they’re cool!). Perhaps if we looked at squid all day, we’d learn squid language!

    As for evidence — I think we don’t know enough about what you need for language to actually say yet. As for FOXP2, it’s something that correlates with _disordered_ language (and then only partially disordered langauge — it’s not like these people have no communication ability at all — it’s just that some aspects of their language has been messed up). Knowing about something that causes _disorders_ is really something entirely different to something that causes language.

    For example, if I took a wheel off your car, your car wouldn’t work very well. But that doesn’t necessarily tell me a whole lot about your car or how it is made. Now as it happens, the situation with language genes is actually far worse, because there’s lots and lots of genes that are involved (no doubt many more than we know about), and they interact with each other and the environment in rather unpredictable ways.

    If you just take a really simple case of some little tiny piece of language, say, what they call your phonological loop (i.e., how many sounds you can remember at one time), then you find that there are many genes that correlate with this. If you have 50 of the good ones and I have only 30, then you’ll have a better memory than me, except that it isn’t that deterministic — just a correlation. So perhaps I have the same number of what we think are the good ones as you, and they’re just guessed at anyway, but I show worse peformance for unknown reasons.

    This is pretty much where we are at now with human genetics — we’ve gone from looking at individual genes that go wrong in families (this is where most breakthroughs have been and what you would have learnt in school — but all the simple stuff is probably identified now) to very recently looking at population genetics where you get two really large population samples that differ on something and look at the differences (or just the correlations if something is quantative). But no-one really knows much about it yet, and there are obvious cases where we know SFA from the correlations (which is almost everything), to things where something is obviously different, but if you get two populations, one with it and without, and look at the differences, you find essentially nothing (e.g., schizophrenia — note that I think stuff has been identified using family comparisons). I saw a talk a few years back by the top geneticist in France, and he suggested that we’d never figure it out and gave reasons (although perhaps he was just a depressing existentialist..)

    So I think the short answer is that I don’t think you can find the evidence right now (I don’t think the neuroscience, the cognition, or the genetics tells use why we are unique in having advanced language skills), and if people tell you otherwise, it basically a hand-waving story.

  12. conrad
    Posted June 28, 2011 at 1:26 am | Permalink

    http://www.youtube.com/watch?v=gnhc1KALHxE

    That’s the cuttlefish video if you haven’t seen it. I reckon they talk about prawns.

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