Dr. Leroy Hood: Deconstructing Disease

Dr. Leroy Hood has a vision of health care in which physicians predict who will develop certain diseases, and then tailor individual drug regimens to cure them. Doctors will have a vast tool kit of tests that will do more than pinpoint disease-causing genes; they'll decode the intricate chemical signals that pass among the DNA, RNA, proteins, and each cell of the body. Solve such puzzles and you could create health-care blueprints to keep people disease-free well into old age.

Hood is the godfather of this emerging branch of science, called systems biology. The key idea is that the human genome is merely a parts list. To understand the disease process, Hood believes, scientists must decode the complex biochemical pathways created by the more than 50,000 proteins that genes produce -- and link what they learn to the whole system. Only then can doctors figure out how to interfere with a pathway to cure or even prevent an illness.

Hood, whose father was an electrical engineer, compares the challenge to figuring out how a transistor radio works: The separate parts aren't very telling until you see how they're assembled into electronic circuits. "When you do that, you understand how radio waves convert to sound waves," says Hood, 67.

Building complete disease models wouldn't be possible without Hood's own inventions. In the early 1980s, he developed a sequencing machine that was later used to map the human genome. He also figured out how to automate the process of synthesizing and sequencing proteins. In 1981, he founded Applied Biosystems Group (ABI ) to commercialize his inventions, and it's still a leading provider of DNA analysis technology, with nearly $2 billion in annual sales.

Hood is known for taking a cross-disciplinary approach to tackling diseases. In 2000 he co-founded the Institute for Systems Biology in Seattle, where 180 specialists in biology, chemistry, math, and physics work together to unlock a range of medical mysteries, from how cancer develops to how the immune system forms in childhood. Hood was one of the first scientists to clone the gene that causes mad cow disease, and now the institute is working on a blood test that could be used on live animals. "We hope ultimately to detect the disease very early and halt it," he says.

Hood fell in love with biology as a high school student in Shelby, Mont., where he was a star quarterback on the football team. His science teacher spotted talent in Hood beyond the gridiron and recruited him to help teach sophomore biology. "I taught out of Scientific American," Hood recalls. In 1956, he brought in an article about the structure of DNA -- he was as blown away by the discovery as his students were. After studying science at California Institute of Technology, Hood earned his M.D. from Johns Hopkins School of Medicine, then returned to Caltech to obtain a PhD in biochemistry. Now, Caltech has teamed up with Hood's institute to form the Nanosystems Biology Cancer Center, which is pursuing "predictive, personalized medicine," says the director, James R. Heath; Hood "sees the future and acts on it."

Big Pharma has yet to catch the systems biology bug. Hood says most drug-company labs still practice the one-gene, one-protein method of chasing down diseases. "They divide science into silos," with the chemists often working separately from the biologists. To encourage more collaboration, Hood's institute developed software tools that he says can get any systems biology lab up and running. "Our policy is open-source," Hood explains. "Anyone can download [the tools]." That's just one device he uses to shift biology's focus from the minutiae to systems as a whole.

By Arlene Weintraub

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