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The Genome That Keeps on Giving

When scientists mapped the human genetic blueprint, people said it would change medicine because we'd be able to get clues about our future health

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Genome sequencing will soon be part of everyday medicine. Image courtesy of Brigham Young University

Last week the Smithsonian’s National Museum Of Natural History announced that in June, 2013, it will open a big exhibit on the human genome to mark the 10th anniversary of the mapping of the human body’s genetic blueprint.

That was no small accomplishment back in the spring of 2003 when the Human Genome Project completed its mission of identifying and determining the sequencing of the roughly 20,000 genes in our DNA. It took at least a billion dollars and 13 years to decipher the puzzle.

To get a sense of how far and how fast the technology has advanced in the past decade, consider that now a genome can be sequenced in less than a day at a cost of somewhere between $3,000 and $5,000.

Getting that down to $1,000 is considered a tipping point, the price at which health care experts believe personal genome mapping will become an everyday medical practice. Already, a scaled-down version called genotyping can be purchased from firms such as 23andMe for $99 and a $9 monthly subscription fee. As Dan Costa wrote for PC Magazine, that entitles you a wide range of personal revelations–in his case that his earwax type is wet and that he has a “typical chance” of going bald, but also that he has a higher than average sensitivity to Warfarin, an often prescribed blood thinner, and that he is almost twice as likely as the average man of European ancestry to develop macular degeneration, or some loss of vision in old age. He also receives updates about any new relevant research.

But what does it all mean?

Costa does wonder how to interpret what he now knows about what’s ticking inside him, although he doesn’t doubt that this kind of self-knowledge will encourage people to get more serious about taking care of themselves. He says he’s going to ratchet up the fruit and veggies in his diet, thanks to that tip about macular degeneration.

But there are other dicey questions. Most geneticists agree that it’s good for people to know about their risk of conditions for which they could take preventive measures, such as breast or ovarian cancer or heart disease. But what about learning you had a genetic marker for Alzheimer’s or Parkinson’s disease, for which, at this point, there is no cure? Or does it make sense to have this kind of data going directly from the testing companies to individuals, without any involvement of a doctor required? (The American Medical Association has already weighed in with a robust “No” on that one.)

And how much weight should genetic risk be given, after all, when many diseases, such as cancer and diabetes, are also tied to plenty of environmental and behavioral factors? Isn’t a genetic marker only an ingredient in a complex stew?

That’s a point at the heart of recent study of identical twins done at Johns Hopkins, which found that genome sequencing isn’t yet the predictor of future health that some people have suggested it could be. Using a mathematical model based on what they knew about the medical histories of twins, the researchers concluded that under the best case scenario, most people would learn they had a somewhat increased risk of at least one disease. But negative results for other diseases didn’t mean they wouldn’t get them–only that they’re at no more risk than the rest of the population. So we’re still talking about a cloudy crystal ball.

Another study, published in the journal Genetics in Medicine, undercuts an argument that wide scale genetic testing will drive up health care costs because people anxious about their results will seek more and more lab tests and followups with doctors. But this study didn’t show that–in fact, the people who received genetic testing didn’t ramp up their use of health care services any more than people who weren’t tested.

Only one thing we can say with certainty: As much as we now know about the human genome, we still have a lot to learn about how we’ll use that knowledge.

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Here’s more of the latest news about genetic research:

Video bonus: Richard Resnick is CEO of a company called GenomeQuest so he definitely has a point of view about how big a role genome sequencing will play in our lives. But he does make a good case in this TED talk.

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