The rapid advance of genetic technology is creating powerful new tools for diagnosing disease as well as serious new ethical issues about the possible misuse of genetic testing, American Cancer Society Professor of Biology Robert A. Weinberg said at an IAP lecture last week.
Professor Weinberg's January 6 talk, "Genetic Diagnosis and Its Societal Impact," opened a series of IAP lectures sponsored by the biology department. Forthcoming session topics include new diet drugs developed by MIT researchers and the possibility of an AIDS vaccine.
"The new genetics will have a greater impact on our lives than any other aspect of modern biology. It will affect us from cradle to grave," Professor Weinberg said.
To date, most genetic tests are for gross abnormalities, such as the extra copy of chromosome 21 that usually causes Down syndrome. "But with the technologies that are developing, we have the possibility of prenatal diagnosis that can, in principle, determine the entire genetic sequence (of a fetus)," Professor Weinberg said.
The impact of such genetic testing is widespread and controversial, he said. For example, he posed the question of whether a positive test for diseases like Huntington's-an inherited disease that hits people in their late 30s, causing degenerative spasms and a gradual loss of mental faculties-justifies terminating a pregnancy.
While aborting all fetuses that test positive for Huntington's disease would eventually eradicate the disease, it also raises strong protests from anti-abortionists, Professor Weinberg noted.
"We are now beginning to wrestle with these issues. They are not so futuristic," he said.
Professor Weinberg said that to date, more than 100 diseases-a number he said is still "small"-have been linked to specific genes. Errors in the sequence of base pairs of genes can lead to diseases or predispositions to cancers and other illnesses because the errors are passed from parent to child. There currently are about 2,000 documented human disease traits.
"It is likely that over the next decade, each of those will be associated with specific genes," he said. "We will probably also discover genes that affect various aspects of the function of the brain like anxiety disorders, manic depression and cognitive ability."
Research into behavioral and cognitive links to genes, as well as into genetic predispositions to diseases or behaviors that are linked to race, brings up explosive ethical issues, Professor Weinberg said. "You now begin to have a form of racism not driven by irrational cultural prisms, but with scientific, reproducible results that 'rationalize' racism with the new genetics."
Other downsides to genetic testing include negative impacts on a person's ability to obtain health insurance, a job or an education, or to marry. He also suspects genetic predisposition could become an excuse for criminals.
"Genetic determinism has a flipside that says everything we do is a consequence of the genes we've inherited rather than our free will, so we may see an abdication of responsibility by individuals such as criminals in the future," he said.
While he said he doesn't hold out much hope that genetic therapy to "repair" defective genes will proliferate any time soon, if ever, Professor Weinberg added that he does believe research such as the international Human Genome Project (HGP) can produce new or preemptive treatments. For example, women with certain inherited breast cancers can already choose prophylactic mastectomies.
About 5 percent of the HGP's research budget is for studying the ethical issues of the new genetics, he said.
While most genetic research to date has focused on major diseases, Professor Weinberg said that in coming years, scientists also will explore genes that affect normal human variabilities, or polymorphisms. "We know almost nothing about genes that determine eye or hair color, weight or the width of one's fingernails," he said.
A version of this article appeared in MIT Tech Talk on January 15, 1997.
