Hailed as an outstanding researcher, mentor, and friend by peers and students, Harvard Genetics professor Philip Leder ’56 died on Feb. 2 after suffering complications from Parkinson’s disease, according to his daughter Micki Leder.

Leder is survived by his wife, three children, and eight grandchildren. He was 85 years old.

A celebrated geneticist, Leder initially rose to fame through his work with Marshall W. Nirenberg in 1964, which led to the discovery of a technique for deciphering nucleotide triplets in the genetic code for all amino acids — helping scientists understand and express the language of DNA. In 1972, Leder became chief of the Laboratory of Molecular Genetics at the National Institute of Child Health and Human Development, where he studied the immune system’s ability to generate a seemingly infinite amount of antibodies.

In 1980, Leder joined Harvard Medical School as the founder of its new Genetics department. In 1983, he created the OncoMouse — a mouse genetically engineered to be more susceptible to cancer; the organism would become crucial to the study of cancer therapy.

Clifford J. Tabin, the current Genetics department chair, said Leder’s leadership helped transform the structure of all Medical School departments thanks to his emphasis on mentoring for junior faculty members.

“He was the first chair of any department to have a mentoring program for faculty, for junior faculty, which now all departments are required to have,” Tabin said. “He really changed the culture across the board at the medical school, because the other chairs either followed suit or as new chairs came in, they wanted to try and build out and replicate aspects of what Phil had done.”

Leder also catalyzed the growth of the Genetics department by outlining clear paths to tenure for new hires, according to Fred Winston, a Medical School professor and one of Leder’s first faculty hires at the Genetics department.

Winston said that before Leder’s arrival, achieving tenure was highly competitive and difficult, adding that Leder’s changes to the process “totally changed the culture” at the Medical School.

“The result of that was faculty were reluctant to teach and spend time on other scholarly activities besides pushing their own research,” Winston said. “When Dr. Leder moved to Harvard Medical School, he totally changed the culture in that, for every junior faculty hired in the Genetics department, it was clear that if they achieved at a high level as judged by people at Harvard and the outside world, that there would be a clear and definite possibility of getting tenure.”

Those who worked with Leder also noted his brilliance as a teacher who could make complex scientific ideas easy to grasp.

Ilan R. Kirsch, the senior vice president of translational medicine at Adaptive Biotechnologies and a postdoctoral fellow with Leder at NICHD, praised Leder’s ability to efficiently present and solve scientific problems.

“In addition to his scientific insight and acumen and integrity, Phil really was one of the most lucid, articulate presenters of scientific information that I’ve ever heard, and certainly was, to some extent, a role model in that regard,” Kirsch said.

Beyond his academic work, however, Leder is remembered by students, colleagues, and friends as an involved and caring mentor.

Winston recalled a poster session he participated in to recruit graduate students to research groups. When no students approached his poster at first, Winston said, he felt “kind of lonely” – that is, until Leder stepped in.

“Phil, supportive as he is, went and found two graduate students who were looking at another poster and brought them over to mine, saying, ‘Here’s a new junior faculty who you should get to know,’” Winston said. “He brought them over to my poster, and those became my first two graduate students.”

Cynthia C. Morton — a professor of Obstetrics, Gynecology, and Reproductive Biology at Harvard Medical School and a former member of Leder’s research group at Harvard — said she experienced a “positive, healthy family culture” while working in Leder’s laboratory.

Morton said one instance of Leder’s immense concern for others occurred when a hurricane hit the area surrounding his laboratory.

“He was walking through his lab, making sure everybody got out,” Morton said.

Colleagues also said Leder left a legacy at the Medical School and beyond by advising many mentees who worked in his research groups.

Richard L. Maas, the chief of the genetics division at Brigham and Women’s Hospital and a former member of Leder’s Harvard research group, said he remembered many pieces of wisdom Leder passed on to others.

“There were a lot of important, powerful lessons that he imparted to his trainees,” Maas said. “How to pick a problem, when to persevere, when to call it quits on something that’s not working, how to share credit, how to collaborate, these kinds of things.”

Those who knew Leder said he had an compelling and motivating sense of humor.

Harvard Genetics professor Jonathan G. Seidman ’71, a former member of Leder’s lab at NICHD, remembered Leder’s talent for seeing the funny side of any situation.

“Phil was really funny,” Seidman said. “He had lots of good stories. People enjoyed being with him. It was just a fun place, and he had a very wry sense of humor. I don’t know how to capture that, but he was really good at finding the humorous parts of anything, including a scientific problem that he thought was humorous.”

Like Seidman, many of Leder’s mentees said they were proud to have worked under him — not just because of his numerous scientific accomplishments, but in light of his personal presence.

“He was a giant, and yet, very modest and humble at the same time,” Morton said. “And I couldn’t have been prouder at any moment to say, ‘I was a postdoc with Phil Leder.’ I just couldn’t wait to tell somebody that, because he was so special.”

—Staff writer Ethan Lee can be reached at ethan.lee@thecrimson.com.