Nearly every day another gene is discovered, mapped along the DNA, or sequenced. Most of the fervor and scientific competition is directed at genes thought to cause diseases, about 100 of which had been found, or at least hinted at, by the end of 1995. The list of disease genes that have either been discovered, or whose location on the genome has been elucidated by more than one laboratory, includes several types of cancer, Huntington's disease, cystic fibrosis, schizophrenia, Alzheimer's, myotonic dystrophy, some forms of epilepsy, neurofibromatosis, improper lipid utilizations that contribute to heart disease and dozens more.
In addition, the list of basic human attributes that have allegedly been traced to specific genes or mapped on chromosome sites is expanding almost daily: from homosexuality to color vision--even a putative obesity gene that makes some people store vast amounts of fat. Many genes that are experienced in adulthood as cancer-promoting turn out to be essential signals for embryonic growth--signals intended to shut down following fetal development. Thus, the search for cancer genes is opening startling windows on basic fetal and infant growth.
So massive is the amount of quarternary nucleotide information that no single computer system is adequate to the task of its data storage and analysis. The Department of Energy stores most of the U.S. database at Los Alamos National Laboratory, using supercomputers originally designed for nuclear weapons and war games use. The European Community recently completed construction of the Bioinformatics Institute in Cambridge, England. Funded at a level of $8.5 million per year, the institute has enough computer power to process information on the more than 300 million human, microbe, plant and animal nucleotides already fully sequenced and the capacity to grow at a rate of 75% per year. Even at that, scientists see the institute as a mere stopgap measure. In order to completely understand how the data that is encoded in DNA ends up controlling a liver cell in one way, operating a neuron in the brain in another manner and functioning improperly in a breast cancer cell, new computer capacities will be needed--ones that can handle more than 100,000 interacting functions simultaneously in real time, Hood says.
All this computer power is needed to help humanity decode and understand its own genetic dictates. The level of complexity in DNA signaling is well beyond the simple binary system used by computers. Ironically, however, the basic DNA code is quite simple. As University of Washington molecular biologist Maynard Olson has noted, the nucleotide database in our DNA computers is only 750 megabytes in size, fills a microscopic amount of space in human eggs or sperm and, once elucidated, any individual's personal genome sequence could be stored on a single CD-ROM.
"The Human Genome Project should get on with producing this disk, on time and under budget," Olson declared in a recent Science magazine editorial.
Geneticist Peter Goodfellow of England's Cambridge University believes that within five years all of the key genes responsible for complex human diseases will have been identified. Even more bullish is Harvey Lodish of the Whitehead Institute, who is convinced that science is just a few years away from having 3-D full-color computer presentations of DNA data for such things as speech, musical ability, body shape and eye color. Indeed, Lodish envisions a time when fetal DNA may be loaded into a computer and parents will be able to "see," via computer, the child's predicted physical appearance and talents--perhaps even hear its simulated voice of the future.
Though such forecasts are controversial, virtually all scientists in the field would agree with Nobel laureate Walter Gilbert's bottom-line prediction: "The results of the Human Genome Project will produce a tremendous shift in the way we can do medicine, and attack problems of human disease. And the understanding that will come from this is likely to give us as people a much stronger feeling of how genetically influenced we are."
Based on their collective writings and presentations at recent scientific meetings, it also seems apparent that human genome scientists would agree with Hood's prediction that within 20 years all Americans will carry credit card-type plastic strips that contain computer readouts of their personal genomes.
"I can't imagine that won't be true," Hood says. "I think that's absolutely a given. Your entire genome and medical history will be on a credit card. You just put it in there [a computer] and a physician will instantly know what he's dealing with. Physicians will really then have to look at humans as complex systems analysis."
Mischievously, Hood enjoys asking physicians to describe what their jobs will be like in 25 years. "They can't do it," he says. "We all have pretty limited imaginations. But physicians can't see how all this will affect them."