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How much can we blame DNA for who we are?

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  • How much can we blame DNA for who we are?


    November 12, 2008 -- I owe an apology to my genes. For years I offhandedly blamed them for certain personal defects conventionally associated with one's hereditary starter pack - my Graves' auto-immune disease, for example, or my hair, which looks like the fibers left behind on the rim of an aspirin bottle after the cotton ball has been removed, only wispier.

    Now it turns out that genes, per se, are simply too feeble to accept responsibility for much of anything. By the traditional definition, genes are those lineups of DNA letters that serve as instructions for piecing together the body's proteins, and, I'm sorry, but the closer we look, the less instructive they seem, less a "blueprint for life" than one of those disappointing two-page Basic Setup booklets that comes with your computer, tells you where to plug it in and then directs you to a Web site for more information.

    Scientists have learned that the canonical "genes" account for an embarrassingly tiny part of the human genome: maybe 1 percent of the three billion paired subunits of DNA that are stuffed into nearly every cell of the body qualify as indisputable protein codes. Scientists are also learning that many of the gene-free regions of our DNA are far more willing to express themselves in ways that have nothing to do with protein manufacture.

    In fact, I can't even make the easy linguistic transition from blaming my genes to blaming my whole DNA, because it's not just about DNA anymore. It's also about DNA's chemical cousin RNA, doing complicated things it wasn't supposed to do. Not long ago, RNA was seen as a bureaucrat, the middle molecule between a gene and a protein, as exemplified by the tidy aphorism, "DNA makes RNA makes protein." Now we find cases of short clips of RNA acting like DNA, transmitting genetic secrets to the next generation directly, without bothering to ask permission. We find cases of RNA acting like a protein, catalyzing chemical reactions, pushing other molecules around or tearing them down.

    For many scientists, the increasingly baroque portrait of the genome that their latest research has revealed, along with the muddying of molecular categories, is to be expected. "It's the normal process of doing science," said Jonathan Beckwith of Harvard Medical School. "You start off simple and you develop complexity."

    Nor are researchers disturbed by any linguistic turbulence that may arise, any confusion over what they mean when they talk about genes.

    "Geneticists happily abuse 'gene' to mean many things in many settings," said Eric Lander of the Broad Institute. "This can be a source of enormous consternation to onlookers who want to understand the conversation, but geneticists aren't bothered."

    For some researchers, though, the parlance of molecular biology is desperately in need of an overhaul, starting with the gene. "The notion of the gene as the atom of biology is very mistaken," said Evelyn Fox Keller, a science historian and author of The Century of the Gene and other books. "DNA does not come equipped with genes. It comes with sequences that are acted on in certain ways by cells. Before you have cells you don't have genes. We have to get away from the underlying assumption of the particulate units of inheritance that we seem so attached to."

    Keller is a fan of the double helix considered both in toto and in situ - in its native cellular setting. "DNA is an enormously powerful resource, the most brilliant invention in evolutionary history," she said.

    Still, she said, "it doesn't do anything by itself." It is a profoundly relational molecule, she said. To focus endlessly on genes, she said, keeps us stuck in a linear, unidirectional and two-dimensional view of life, in which instructions are read out and dutifully followed.

    "What makes DNA a living molecule is the dynamics of it, and a dynamic vocabulary would be helpful," she said. "I talk about trying to verb biology." And to renoun it as well. Writing last year in the journal PloS One, Keller and David Harel of the Weizmann Institute of Science suggested as an alternative to gene the word dene, which they said could be used to connote any DNA sequence that plays a role in the cell. So far, Keller admits, it has yet to catch on.

    Complex as our genome is, it can be comprehended: Our cells do it every day. Yet as the physician and essayist Lewis Thomas once noted, his liver was much smarter than he was, and he would rather be asked to pilot a 747 jet over Denver than to assume control of his liver. "Nothing would save me or my liver, if I were in charge," he wrote.

  • #2
    wow, very interesting point.

    a new way to define who we are without using that one word- genes.
    It seems as if one fails to conceive
    The meaning my name strives to achieve

    To a biological form you cannot relate-
    Because a reproductive cell is a gamete not gamate!

    It means to unite, -to become consolidated
    So without me in a.com, is there hope we'd be amalgamated?

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    • #3
      i love genetics, in a weird tormented loves tormentor way <3

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      • #4
        This kind of investigations will have a huge impact on society. Still i am really curious about it. They must use it in a positive way though.

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