Human-Chimp Speciation

Humans and chimps did not undergo a speciation event. Some pair of species (one an ancestor of humans, the other of chimps) speciated. It was thought that this event occurred approximately 6.5-7.4 million years ago, based on fossil evidence. A new paper coming out in the week’s issue of Nature, however, suggests that the speciation event was sloppy. The authors argue, based on differing amounts of divergence between humans and chimps in different parts of the genome, that there was some hybridization and the speciation event extended until 5.4 million years ago. You can read about the study here, here, here, here, and here. The Nature article does not appear to be available yet, so I can’t really comment on the methods.


  1. #1 IndianCowboy
    May 17, 2006

    you genetical people seem to have all the fun these days. I’m pretty sure all bioanthropologists will be out of a job within 10 years if you people keep this up. Evolution of the brain, the origin of the hominin tribe, human-neandertal hybridization… JUST NOT FAIR!

    Ok I’m done whining. Makes sense. I’ve always thought that speciation events would tend to be sloppy affairs particularly in the case of sympatric (does it even exist?) and incomplete allopatric speciation.

    There are a lot of mammals that can interbreed and produce fertile offspring, but don’t. So it seems logical that there are those that can, and do. Been some interesting stuff with baboons with borderzone hybrid types taht persist as hybrid groups. Which is also interesting.

    K, no more rambling.

  2. #2 Wabin
    May 17, 2006

    I’m not sure I see what is so surprising here. Osada and Wu came to the same conclusion (without the dates, I guess) a year and a half ago. Patterson et al. barely cite that paper (in fact the citation in the online version doesn’t make sense). Ah well. It is Nature after all…
    For reference, the Patterson paper is at:

    and the Osada and Wu at:

  3. #3 razib
    May 17, 2006

    shit dog, this is dope!

  4. #4 RPM
    May 17, 2006

    Larger data set? Date that conflict with the paradigm? I haven’t looked closely at either this new paper or the Osada and Wu publication, so I can’t say what makes this one different.

  5. #5 Doug
    May 17, 2006

    Animal hybrids are known to occur today – liger [lion/tiger], wolphin [whale/dolphin] and zonkey [zebra/donkey] – and most recently the grizzly/polar bear.

    That this may have happened in the past to primates that were proto-humans is not that difficult to comprehend.

    When genomes of the bonobo, gorilla, gibbon and orangutan are completed, maybe there will be more information to explore this viable idea.

  6. #6 Boknekht
    May 18, 2006

    Why are we, & how did we end up so dissimilar to the extant higher primates, which all seem more like one another than any of them do to us, pheno-morphologically speaking?
    What existed out there millions of years ago, i wonder? – any other varieties of bipedal, relatively hairless, man-like apes? I wanna know!:(

  7. #7 Robert
    May 19, 2006

    Of course some of us a relatively more or less hairless 🙂

    One of my work mates, when I was much younger, was far more hairy than the norm. Without a shirt, he looked positively chimp-like. He called it “fur” too!

    In my own case, I am curious if male pattern baldness occurs with any of the other primates?


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