February 25, 2003Voices on DNABy THE NEW YORK TIMES esearchers
and others tell how DNA's discovery, and the decades of genetic
research that followed, affected their work and lives.
The Watson-Crick discovery changed the whole paradigm. Until then nobody even knew what a gene was. But because of the elegance of the structure, it was overpowering. It changed our whole way of thinking. Just by looking at it, you could see the way DNA worked — by the way all those A's and T's and C's and G's lining up so nicely, you could see that there had to be a code. The genome sequence is different. It's just really a technical accomplishment. It adds to all the work that had gone on in the previous 25 years, when we built the edifice, figured out how you go from DNA to a phenotype. But in many ways we'd already done all of it, though on a much smaller scale. We had already sequenced genes, we'd already even sequenced the genomes of small organisms. I look at the sequencing of the human genome as the end of the beginning. Now we have the human genome, and we have to figure out how it works, how the gene does what it does. In my opinion, the next exciting frontier is the nervous system, how the brain works, how it develops, how the various components of the brain connect, how genes control its organization and development. CYNTHIA KENYON When you can use genetics to approach a problem, what you can do is you can ask, Are there genes for this? You can just take animals, like these little C. elegans worms we work on and change genes at random just by treating them with something that causes mutation. We found that mutations in a gene called daf-2 doubled life span. And it's not just that they made the animals live long, which is definitely interesting. But what was really breathtaking is that the animals stayed young for a really long time. We've been able to extend the lifetime of worms sixfold, actually, by changing several different genes. These long-lived animals do not get diseases of aging until they get older. It's not just the postponement of age, it's the extension of youthfulness. I think it's very reasonable to think that we could increase life span by a couple of decades for most people with a concomitant increase in youthfulness.
When my mother went to medical school, DNA was an exciting discovery with little medical application. When I was in school, the idea of a predictive genetic test for cancer risk was science fiction. Now, families in my clinic use DNA tests every day to estimate breast, ovarian and colon cancer risk. Very recently, we have shown that increased surveillance or preventive surgery after genetic testing can find early stage cancers. We also now know that preventive surgeries of ovary, breast, thyroid or colon will lower cancer risk. This is an important new emotional element for families touched by cancer, as they come to understand that "genetics is not destiny." Families can now use DNA tests to see the future and change it. MARY-CLAIRE KING I could have sequenced my own genome if I wanted to, but I chose not to. I have far better things to do with the equipment and money and time. One is driven to these questions by family history. In my family, the causes of severe morbidity and mortality are preventable — infectious diseases for which we now get vaccinations — so knowing those genes would not make much of a difference to me.
The real significance of the 124 postconviction DNA exonerations is what we can learn about the rest of the criminal justice system. All the causes of wrongful convictions are at play: mistaken identifications, false confessions, police and prosecutorial misconduct, bad lawyers, junk forensic science. Take microscopic hair comparison. Now we know from the F.B.I. itself that — even when it's their own examiners, who are the best in the world — that at least 11 percent of the time, when you test the mitochondrial DNA, the conclusions are incorrect. This is a major scandal.
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