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Scientists Make Fish Grow "Hands" In Experiment Revealing How Fins Became Limbs 110

Posted by samzenpus
from the hands-to-hold-you dept.
An anonymous reader writes "While fossils have long shown that limbs evolved from fins, scientists have shown live in the laboratory how the transition may have happened. Researchers said that the new study published in the journal Developmental Cell offers evidence revealing that the development of hands and feet occurred through the acquisition of new DNA elements capable of activating specific genes."
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Scientists Make Fish Grow "Hands" In Experiment Revealing How Fins Became Limbs

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  • Bizarre (Score:1, Insightful)

    by cfulmer (3166) on Monday December 17, 2012 @04:31PM (#42317175) Homepage Journal

    So, the hand genes were just sitting around, waiting to be 'activated' by specific DNA?

    I think that means that either Intelligent Design is real or we don't have really good terminology to describe what actually happened.

  • Re:Bizarre (Score:5, Insightful)

    by viperidaenz (2515578) on Monday December 17, 2012 @04:50PM (#42317497)

    ....or you don't have a good understand of what happened.

  • Re:Bizarre (Score:5, Insightful)

    by Chris Burke (6130) on Monday December 17, 2012 @05:03PM (#42317721) Homepage

    So, the hand genes were just sitting around, waiting to be 'activated' by specific DNA?

    Kinda maybe but not really? There's no gene for hands. There are genes involved in growing those tissues which comprise limbs, which are in turn controlled by other genes. Control those genes one way, you get fins, another way, you get "hands". The controlled genes were already present in the fish, and being used to make fins. Add a new mouse gene that controls those other genes a different way and you get something more like a hand.

    As a ridiculously coarse analogy, it's like saying the standard C library has the code for a chess game because if you take a tic-tac-toe game and then re-arrange a bunch of the code that controls how the stdlib functions are called you get chess instead. Yes there are important pieces being re-used but there's more to it than that.

    There's no problem with the terminology, and absolutely no need to resort to ID to explain this. Our bodies re-use the chemical machinery of life forms from billions of years ago. Just in different ways. Evolving new mechanisms for controlling that machinery is still evolution.

  • Re:Bizarre (Score:5, Insightful)

    by JesseMcDonald (536341) on Monday December 17, 2012 @05:17PM (#42317913) Homepage

    First, they didn't actually manage to grow hands. The closest they were able to achieve was "autopods", a precursor somewhere between hands and fins. The cause of this difference was a transplanted mouse gene which increased the production of a certain protein involved in selection and development of different kinds of tissue.

    The real lesson from this is that small changes in DNA can have large effects on physiology. A bit more of a certain protein at the right point in development and you get autopods instead of fins. A few other minor changes and you might even get something approaching real hands.

    It isn't that fish have unused DNA lying around which can be "activated" to produce hands; rather, the genetic codes for fins and hands are very similar, perhaps differing by just a couple of mutations. This similarity is evidence in favor of common descent. Why would a "designer" put in the effort to make the DNA so similar? No doubt, if our own experience as designers is anything to go by, it would be far easier to achieve ideal fins and ideal hands without that constraint. Hands and fins differentiated only by the presence of a few specific proteins is perfectly consistent, however, with inherited genetic traits and natural selection.

  • Re:Bizarre (Score:3, Insightful)

    by Anonymous Coward on Monday December 17, 2012 @05:25PM (#42318009)

    So, the hand genes were just sitting around, waiting to be 'activated' by specific DNA?

    No. But this is like a game of telephone. It starts and ends like this,

    1. Scientists try to do some experiments to see if they can manipulate genes to see which ones differentiate limbs from fins. You know, since evolution says fish => land. (also land to fins, like whales)

    2. After lots of work, scientists get a 4-day embryos that die that have different shaped fins, like autopods. So they found gene that may be a candidate.

    3. Scientists communicate to press "Of course, we haven't been able to grow hands!"

    4. Slashdot links to an article "Scientists Make Fish Grow Hands!!!!!!"

    5. you,

    I think that means that either Intelligent Design is real or we don't have really good terminology to describe what actually happened.

    6. Scientists: "WTF?"

    I guess next week in the news, "Scientists discover green man on Mars!!" and then someone will poast "It is a sign of creator!" and will be modded +5 Insightful.

I find you lack of faith in the forth dithturbing. - Darse ("Darth") Vader

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