Stephen J. O'Brien, a nationally known geneticist, conservationist and expert on animal DNA, is convinced that cures for such diseases as cancer, AIDS and Alzheimer's might be locked up in our cats.

O'Brien, chief of the Laboratory of Genomic Diversity at the National Cancer Institute in Frederick, used a cat's DNA to help Canadian police solve a murder and has spent five years researching the genetics of the African cheetah.

He has written extensively about cats afflicted with the feline equivalent of acquired immune deficiency syndrome and helped wildlife officials save the endangered Florida panther by breeding it with a Texas cougar.

Why does a scientist with a doctorate from Cornell, paid by the National Institutes of Health to study cancer, focus on cats?

O'Brien said that the search for a cancer cure might lie in unraveling the genetic makeup of animals that contract the disease, such as cats.

"Many of our genetic secrets are trapped in the animal world," said O'Brien, 53, of Frederick.

Consider Darwin's theory of evolution, he said. An animal's ability to fight off diseases and survive -- whether it's a cat or a person -- depends on its genetic makeup, he said.

"Throughout history, there have been 100 million species of mammals on this planet and only 5,000 species are alive today. These are the survivors, and understanding how they've managed to survive has a direct bearing on human health," he said.

O'Brien also pointed out that he spends a major portion of his time studying human genetics, not cats.

He was part of a team of federal scientists that with other scientific groups reported breakthrough research in 1996 that the human gene labeled CCR5 plays a significant role in human immunodeficiency virus infection and the progression of AIDS.

"Even if you took away his work with cats, he's still contributed a lot to cancer research," said Dr. Robert C. Gallo, who heads the University of Maryland's Institute for Human Virology in Baltimore.

Gallo praised O'Brien as a brilliant scientist whose enthusiasm for life and his work is infectious.

"He has really good ideas and tremendous intellect, and he uses that intellect in the way he attacks his work," Gallo said.

O'Brien began considering a career in science as a teen-ager in Bethesda when he was working at one of his first summer jobs.

"I used to drive a cab and a lot of times I'd have to ferry scientists from NIH [the National Institutes of Health in Bethesda] to Washington so they could hit the hot spots downtown," O'Brien said. "I knew then that was for me."

He earned a degree in biology from St. Francis College in Loretto, Pa., in 1966, and his doctorate in genetics from Cornell in 1971. He was hired a year later as a geneticist for the virus cancer program at the National Cancer Institute, which is an arm of NIH.

The early 1970s were a good time to focus on genetics and cancer viruses, he said.

"In the early '70s, Nixon declared a war on cancer, and the government began an all-out assault on it," O'Brien said.

He was assigned to examine ways that cancer-causing viruses interact with their host's genes. To conduct his research, he had to select an animal to study, and he chose felines for one reason. "Nobody else was working on cats," he said.

In 26 years, O'Brien has become something of an expert on cats, both foreign and domestic.

He has written articles about them for Scientific American, Nature and National Geographic and is an adjunct professor of genetics at seven colleges, including Johns Hopkins and the University of Maryland. He also is co-director of New Opportunities in Health Sciences, a research lab in Front Royal, Va., operated by the National Cancer Institute and the Smithsonian Institution to study genetics and help save endangered species such as the leopard and the cheetah.

Cheetahs remain a particular fascination -- and not just because their 70 mph foot speed makes them the world's fastest land animal.

There are 11,000 surviving cheetahs, he said, but the species might be in danger of dying out partly because diminished gene pools make them vulnerable to diseases.

Scientists believe the same cataclysmic event that wiped out the mastodon about 10,000 years ago -- a type of global ice age -- killed most of the cheetahs that up until then lived around the world. It shriveled their gene pool and limited their range to a portion of Africa.

"They've suffered from a genetic hangover ever since," he said.

O'Brien's reputation with cats led the Royal Canadian Mounted Police to seek his help in 1995 when they discovered the body of a 32-year-old mother of five from Prince Edward Island in a shallow grave.

Police had found a jacket with the victim's blood on it in a field but the prime suspect, the victim's estranged boyfriend, denied owning it.

Police noticed white hairs on the jacket and that the suspect, Douglas Beamish, shared his parents' home with a white American shorthair cat named Snowball.

The Mounties called O'Brien after their forensic experts found that they could determine only that the hairs had come from some type of cat -- but could not link them directly to Snowball.

At the time he was called, O'Brien was drawing up a first-of-its-kind genetic map of cats.

O'Brien had police bring him a blood sample from Snowball. (To identify a cat's genes takes only a blood sample.) He also contacted Dr. Lisa Forman, a colleague at Cellmark Diagnostic Laboratories, a Rockville lab that specializes in forensic DNA analysis.

Using the root of one of 27 hairs from the jacket and comparing its DNA to Snowball and to 20 other cats on the island, O'Brien and Forman determined that it was Snowball's hair on the jacket.

After O'Brien testified, a Prince Edward Island jury convicted Beamish of second-degree murder, and he was sentenced in 1996 to 18 years in prison without parole. It became the first time DNA from a pet was used in a murder trial in North America, according to a 1997 article in Nature.

These days, O'Brien works on his own medical mysteries.

Among them is why domestic cats contract feline immunodeficiency virus, a disease that attacks their T-cells like HIV, while tigers and other wild cats have a gene that resists it.

"If you can find a gene that resists HIV in cats or in humans, that's a step in the right direction," he said. "The point is that all of us animals are in this struggle for survival together."

Pub Date: 8/19/98