Dr. Leder, who more than 30 years ago became a co-holder of the first US patent on an animal, the OncoMouse, was 85 when he died Feb. 2 in his home in the Brookline part of Chestnut Hill of complications from Parkinsons disease.

In a tribute posted on a National Institutes of Health website, Dr. Michael M. Gottesman said Dr. Leder was among the worlds most accomplished molecular geneticists.

During Dr. Leders postdoctoral studies at the NIH in the early 1960s, he was recruited by Nirenberg to work on untangling the genetic code.

Their experiments definitively elucidated the triplet nature of the genetic code and culminated in its full deciphering helped set the stage for the revolution in molecular genetic research that Phil himself would continue to lead for the next three decades, wrote Gottesman, who is the NIHs deputy director for Intramural Research and chief of the Laboratory of Cell Biology at the Center for Cancer Research of the National Cancer Institute.

In a eulogy at Dr. Leders funeral, Dr. David Livingston, a Harvard geneticist, said he was brilliant, bold, very good-humored, and blessed with exceptional scientific insight and creativity.

Livingston, who had been Dr. Leders second research fellow at the NIH, added that early on, it became readily apparent that a natural eloquence infused his oral and written scientific discourse.

The groundbreaking research Dr. Leder and Nirenberg conducted came about in part because of the looming prospect of military service. Instead, he volunteered to serve in the US Public Health Service.

I got drafted, so I applied for a position in the Public Health Service, which supplied physicians and scientists to the National Institutes of Health in Bethesda, Dr. Leder said in a 2012 interview with a publication of the American Society for Biochemistry and Molecular Biology. A friend at NIH told me that I ought to meet Marshall Nirenberg because he was doing interesting experiments with the genetic code. Frankly, I didnt know anything about the genetic code. But I went to see Marshall, and he explained to me what he was doing and its importance.

Their research was in competition with work in another laboratory run by Severo Ochoa, a Nobel Prize-winner, and there was a mad race to the finish, Dr. Leder recalled.

I couldnt sleep for days at a time because of the excitement! I must admit it was very competitive; theres no question about that, he added. I would go to bed thinking about the next days experiments and then jump out of bed in the morning and rush to the laboratory. I stayed late at night. It was a lot of work but the intellectual excitement was enormous.

After about 18 years, Dr. Leder left the NIH at the outset of the 1980s to become founding chairman of Harvard Medical Schools department of genetics, where he stayed until 2008.

Working with Timothy Stewart in 1988, he was awarded the first patent on the OncoMouse, an animal genetically engineered to have a predisposition for cancer, which revolutionized the study and treatment of the disease, George Q. Daley, dean of the faculty of medicine at Harvard, said in a statement. Additionally, Phils research into Burkitts lymphoma was instrumental to understanding the origin of tumors with antibody-producing cells.

Dr. Leders many honors included the Albert Lasker Award for Basic Medical Research; the Heineken Prize from the Royal Netherlands Academy of Arts and Sciences; the US National Medal of Science; and the William Allan Medal from the American Society of Human Genetics.

For his many accomplishments, he was extremely modest. He really didnt like to talk about himself much, said his son Ben of Westwood. What he loved about science was the actual work, and thats what really motivated him.

Scientists such as Livingston, who worked with Dr. Leder early in their own careers, considered him a key mentor.

I shall miss Phil forever, Livingston said in his eulogy. Indeed, only rarely has a week passed when I havent thought of him. If the past is any prologue, my abiding hope will be that, when faced with a particularly potent scientific challenge, some of his mentoring magic will spontaneously take hold and point me in one of those special, Phil Leder-like directions.

Although Dr. Leders accomplishments were lasting, he began focusing more on family and subsequent generations as he neared and then entered his retirement years.

What a wonderful ride it has been, he wrote in 2001 for an anniversary report of his Harvard class. But I now see more clearly than ever before that whatever modest gift of knowledge my colleagues and I have been able to turn over to posterity, it has been poor by comparison to the thrill of seeing our grandchildren walk off into the future.

Born in Washington, D.C., on Nov. 19, 1934, Philip Leder grew up in Washington and in Arlington, Va., the only child of George Leder and Jacqueline Burke.

Dr. Leder graduated from Western High School in Washington and went to Harvard, from which he received a bachelors degree in 1956. He graduated from Harvard Medical School four years later.

In 1959, he married Aya Brudner. They had three children and worked together on research.

I continue to collaborate with my wife, Aya, in the remarkable field of molecular genetics, he wrote for the 40th anniversary report of his Harvard class. Lately, however, we find ourselves occasionally sneaking off to New Hampshire, where we have a second home, a canoe, snowshoes, and lots of opportunity to observe nature in real time.

A service has been held for Dr. Leder, who in addition to his wife, Aya, and son, Ben, leaves a daughter, Micki of Washington, D.C.; another son, Ethan of Bethesda, Md.; and eight grandchildren.

Ive discovered that great joy comes from grandchildren, Dr. Leder wrote 50 years after graduating from Harvard College.

Eight grandchildren, he added, can easily shrink a fairly successful career down to its appropriate proportions. In the next few years Ill retire from a life in genetics, which Ive loved, from the genetic code to the human genome. But I wont retire from those grandchildren, and I suspect that many of you feel exactly the same way.

Bryan Marquard can be reached at bryan.marquard@globe.com.

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Dr. Philip Leder, Harvard researcher who illuminated the role of genetics in cancer, dies at 85 - The Boston Globe