Will Science Create a
Perfect Society?

DNA Detectives

The human body is made up of about 100 trillion cells. Most cells have a nucleus. Inside each nucleus are 46 packets called chromosomes. Each chromosome contains a single, tightly coiled, threadlike molecule called DNA. It is estimated that within the DNA there are up to 100,000 genes, positioned something like towns and cities along a major highway. Our genes largely determine every characteristic in our body—our development in the womb, our gender and physical characteristics, and our growth to adulthood. Scientists also believe that our DNA includes a "clock" that determines how long we will live.

The DNA of animals and humans is remarkably similar. For example, the genetic makeup of chimpanzees differs from that of humans by only 1 percent. Still, that gap is ten times wider than the differences between the DNA of any two humans. Nevertheless, it is those infinitesimal differences that account for the many features that make each of us a unique individual.

A little less than ten years ago, scientists undertook a complex task—to determine the precise order of chemical units in human DNA. This task, known as the Human Genome Project, is ambitious and enormous, and it will cost billions of dollars. The data collected will be enough to fill an estimated 200 volumes, with each volume the size of a 1,000-page telephone book. To read all this information, a person would have to be at it 24 hours a day for 26 years!

Often overlooked in the media is the fact that once this information is accumulated, it will still have to be interpreted. New tools will be needed to analyze the data. It is one thing to identify genes; it is quite another to know what they do and how they interact to build a human. One eminent biologist called the Human Genome Project "the Holy Grail of Genetics." However, a more down-to-earth description was suggested by geneticist Eric Lander: "It's a parts list," he says. "If I gave you the parts list for the Boeing 777 and it had 100,000 parts, I don't think you could screw it together and you certainly wouldn't understand why it flew."