Seeking Our Genetic Fate

Personal genomics companies offer forecasts of disease risk, but the science is still evolving.

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By Patrick Barry, Science News

“RESISTANT” shouts the title of Lindsay Richman’s post. Apparently, she was elated to learn that her DNA reduces her susceptibility to norovirus infections, the principal cause of the common stomach flu.

So she posted a comment on a discussion board on the website for 23andMe, a company based in Mountain View, Calif., that specializes in the fledgling industry of personal genomics. To get a glimpse of her own DNA, Richman had sent the company $400 and a vial of her spit. From her point of view, what happened next was a mystery — a black box. But a few weeks later, out popped her results on a password-protected website, complete with social networking tools for sharing and discussing her genetic inheritance with other customers.

In the string of online responses to Richman’s post, others who share her genetic good fortune compared notes on the last time they’d had any symptoms of stomach flu. Richman, a 26-year-old real estate agent in New York City, hasn’t had stomach flu since she was 8, she wrote.

In other discussions, people compared their genetic profiles and brainstormed on how lifestyle choices and environmental exposures might influence their risks for various conditions, such as Parkinson’s disease and prostate cancer.

Now that prices charged by personal genomics companies such as 23andMe, Navigenics, deCODE genetics and DNA Direct have dropped, ranging from a few hundred to a few thousand dollars, many people curious about their genetic inheritance, and how it relates to their health, have easier access to DNA testing.

Serving to “crowdsource” the search for new links among genes, behavior and disease, these companies’ customers represent a small army of amateur genome sleuths who could prove to be a new force in pushing genomic research forward. But the genetic report cards these amateurs are reading may not be as definitive as they assume. Despite progress in linking genetic differences with disease risk and other traits, the predictive power of these links has fallen short of expectations.

In April, the New England Journal of Medicine published a review and a set of essays grappling with this shortfall in DNA’s predictive power and searching for the best way to take research forward. An essay by Peter Kraft and David Hunter, epidemiologists at the Harvard School of Public Health in Boston, was revealingly titled, “Genetic risk prediction — are we there yet?”

Their answer, in a nutshell: No. Which leads to the crucial question of what, exactly, customers of personal genomics companies are looking at when logging on to the digital oracle to peek at their genetic fates.

The leap from a tube of saliva to a ledger of traits, health risks and ancestral history involves a lot of science — some credible, some flimsy. As more and more people become consumers of genetic information services, these people may want to first open that black box and take a good look inside.

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