Scientist: Human gene map quantum leap in road to recovery

Tuesday, June 27th 2000, 12:00 am
By: News On 6

Most candidate genes for the "ugly human diseases" will soon be identified, eventually resulting in the early diagnosis of many illnesses, says Brown scientist.

By ARIEL SABAR / The Providence Journal

PROVIDENCE -- Embedded in each cell in our body is a code for plenty of the obvious things about us, such as the color of our eyes or our height. But human DNA also holds many things we can't see. Its code can predict with near certainty that we will become ill or even die from crippling genetic disorders such as Huntington's and Alzheimer's disease.

Eric A. Hendrickson, a molecular geneticist at Brown University, thinks a lot about such things. And as he sees it, the greatest promise of mapping the human genetic code lies in finding and defusing these genetic time bombs before they take lives. The announcement yesterday that scientists had completed a rough draft of the code, he says, is a quantum leap toward such a goal. Even if treatment could still be a half-century or more away, the potential for early diagnosis is now within arm's reach.

"There's no question that this is a very significant milestone," Hendrickson said yesterday in a laboratory office piled to the ceiling with scientific journals. "In the next couple of years, most candidate genes for all the ugly human diseases will be identified, which is a huge step forward."

Hendrickson, 43, a wiry, athletic man who paced through his lab yesterday in shorts, T-shirt and sandals, also sees windfalls for his own field of research. He studies how the body repairs damaged DNA, damage that can lead to several kinds of cancer. Whether your body has the tools to mend the damage is itself governed by genes. Hendrickson says that a complete map of the genetic code will help researchers more fully identify those genes and understand why some people have healthy ones and others don't.

Eventually, as the medical science of gene-replacement therapy advances, doctors may find a reliable way to replace disease-causing genes with healthy ones.

Genes for some of the most common genetic disorders, including Huntington's, Alzheimer's, and breast and colon cancers, have been identified over the past decade through conventional research. But a full map of the human genome will speed research into other disorders, in particular such prolific killers as other cancers and heart disease, whose genetic markers are more complex and thus trickier to tease out. Research even suggests a genetic basis to some mental illnesses, such as schizophrenia, depression and even alcoholism.

Hendrickson shares the concerns of some critics of genetic mapping.

Insurance companies could demand that customers turn over their genetic code and then deny coverage to those with defective genes. Groups could press to make science fiction reality by creating a more perfect human being -- one that was smarter, faster and perhaps better looking. Though that might sound appealing, a human race so homogeneous would be at risk of sudden extermination, Hendrickson says, because the lack of genetic diversity would limit its defenses against contagious diseases.

There are also fears about social engineering, ones fueled in part by memories of the Holocaust and, more recently, of "ethnic cleansing" in the Balkans. In China, which is spending millions of dollars on genetic research, a law was passed in 1994 discouraging people with genetic diseases from marrying and having children.

In addition, questions linger about whether companies will seek to patent parts of the genetic code, drawing huge profits from research that was largely paid for by U.S. taxpayers.

On balance, however, Hendrickson sees more reason for celebration than despair. "I think the downside will be minimal and/or can be controlled, and I think the upside can be huge."