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Fins To Feet

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5 comments to Fins To Feet

  • nighthiker

    I think this would be too basic a mistake for the researches (and Nature’s peer review) to commit , so I’m likely wrong, but… Didn’t lobe-finned fish appear before their ray-finned cousins? If so, wouldn’t it be more logical to assume those genes appeared in ray finned fish, rather than disappeared in the tetrapod ancestors? The fish that gained those genes then diverged into all the ray finned fish we see today, while the ones that didn’t originated the tetrapods before mostly dying out. So when they take those genes out the fish simply revert to something closer to how they were before the gene appeared, i.e. closer to lobe-finned fish. It makes more sense and still fits the embryology findings mentioned, it looks to me.

  • nighthiker

    Errata:

    After looking it up online (my copy of “The Greatest Show” isn’t at hand at the moment), it actually looks like ray-finned fish came first (at least have older, if incomplete, fossil records) than lobe-finned ones – they were just much less common than lobe-finned until the late Devonian. If so, then I guess I was wrong indeed.

  • Evan,

    For one point, the “swim bladder” apparently evolved as a lung, then transformed into a flotation organ. For another, ray-finned fishes also have them.

    For another, it’s possible that Zhang and Akimenko are explaining how a ray-finned ancestor evolved into the lobe-finned fishes. I don’t have easy access to Nature and can’t check–does Steve have their online version?

  • Bob, I have no idea why the preceding message is headed “Evan”. Sorry.

  • azinyk

    I think that there are something like 6 species of lungfish and 2 species of lobe-finned fish, compared to about 25,000 species of ray-finned fishes. So there might be more ray-finned genomes sequenced to compare to.

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