Scientists probe genomes, looking for what makes us unique

By studying a person's DNA, researchers may revolutionize medical practice. But some warn that it could unfairly stigmatize individuals.

The journal Science has published its choice for the most important scientific breakthrough of 2007. It's about you, me, and everyone else on the planet. This is the year in which technology made it much faster and easier to scan through large portions of an individual's genome. Many DNA researchers now are looking for signs of individual human uniqueness. As a result, the journal says, "we have moved from asking what in our DNA makes us human to striving to know what in my DNA makes me, me."

Scientists pursuing this new research goal already are finding indications that, while we all share the major part of our species' genetic heritage, there are enough differences from person to person to make every individual genetically unique.

Even identical twins, who share the same genome, may exhibit differences in how their genes are expressed. Humanity's grand biological unity is spiced with individual diversity.

The journal finds the new potential to discover such individual differences "both exhilarating and terrifying." It's exhilarating because we are beginning an adventure of self discovery that scientist explorers could only dream about a couple of decades ago. That, in itself, can be terrifying.

The explorers of this new world also find it terrifying to realize how unwise and premature use of this new knowledge could unfairly stigmatize individuals. Perfectly healthy people could be marked as "at risk" for certain maladies when the so-called genetic "risk factors" are poorly understood.

Eric Topol, director of Scripps Genomic Medicine at the Scripps Clinic in La Jolla, Calif., warned about this in an opinion piece Dec. 22 in The Wall Street Journal. He expects that one day knowledge of a person's genome may revolutionize medical practice. But he warned that "the revolution is far from complete." He explained, "most disease risk genes have not yet been found, the genes which cancel out the risk ... are still largely unknown, and many diseases and conditions have not even been studied."

In spite of such caveats, a new business has sprung up which Science's editor Donald Kennedy says "is creating a somewhat dubious niche market for having one's genome "done." Send in a saliva sample from a swab swiped inside your cheek and one of these companies will scan it for known "markers" linked to various biological traits. It costs about $1,000 to $2,500.

The journal warns that "most common disease markers identified so far raise risks only slightly, but they could cause needless worry." Also, with today's lack of adequate privacy safeguards, that dubious information might be used by insurance companies or employers to discriminate against individuals. The journal adds that, having your DNA scan on record "exposes your relatives' DNA, too."

If that isn't enough reason for caution, Dr. Topol pointed out that the DNA scan may not even be relevant to the purchaser. He explained that "much of our disease-related genomic knowledge is limited to one ancestry" – European ancestry. People of African or Asian ancestry buying a DNA scan "are getting shortchanged," he said.

Meanwhile, we can celebrate our diversity as scientists have linked DNA differences to healthy bodies and productive lives.

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