The Secret of Life

• Share

(2 of 3)

On the other hand, we are learning that each letter in that text can spell the difference between blond and brunet, tall and short, life and death. A woman who carries a mutation in the BRCA1 gene can have a seven times greater chance of developing breast cancer. Scientists in Utah last week announced the discovery of a gene that seems to predispose carriers to depression. We are learning these things in part because of Watson, who, having revealed the simplicity of DNA's structure, wanted to explore the complexity of its function. He helped persuade Congress to fund the Human Genome Project, an attempt to decode the more than 3 billion letters of the complete human genome. Under competitive pressure from nimble private scientists, the goal was achieved ahead of schedule and under budget. In June 2000, when Bill Clinton and Tony Blair announced that the first rough draft of the genome was complete, Clinton declared that "without a doubt, this is the most important, most wondrous map ever produced by humankind." It was enough to fill 200 phone books at 1,000 pages each, or 75,490 pages of the New York Times. And it marked the turning point in the transformation of medicine from treating disease to preventing it altogether.

Each day now, as we discover where we are vulnerable, we move closer to designing drugs to protect us. Gene therapy allows doctors to introduce some handy gene into the body like a little rescue squad, to help produce enzymes that because of some faulty gene, the body can't make on its own. When we finally find cures for cancers, they will reflect the secrets of how our genes fight some cancers and yield to others. Drugs like Herceptin for breast cancer and Gleevec for leukemia work by blocking the chemical signal that tells the cancer to grow. They herald the day when we can look back on the traditional slashing and burning of cancer patients as having been as primitive as bloodletting.

And these new treatments are only a beginning. Genomics is already considered hopelessly 20th century by the scientists who have moved on to proteomics, the study of the proteins for which the genes provide the instructions. Since a typical gene may yield as many as 20,500 different kinds of proteins, scientists are only now figuring out how to begin to figure them out. Researchers don't even know how many proteins there are or how they fold, which means among other things that a whole new kind of machine is needed to study them. The new computers are coming to life. IBM models its newest ones--computers that act like cells and fix themselves wherever they break--after DNA. The quantity of information is so vast, we have to invent new numbers to measure it: not just terabytes (a trillion bits of genetic data) but petabytes (equivalent to half the contents of all the academic libraries in America), exabytes, yottabytes and zettabytes. All the words ever uttered by everyone who ever lived would amount to five exabytes. The speed of discovery leaves even our imaginations behind.