David Baltimore

David Baltimore, a pathbreaking molecular biologist who shared the 1975 Nobel Prize for discovering reverse transcriptase and later led Caltech, died September 6, 2025, at his home in Woods Hole, Massachusetts. He died of complications from several cancers at the age of 87.

Born March 7, 1938, in New York City, Baltimore earned a chemistry degree from Swarthmore College in 1960 and a Ph.D. from Rockefeller University in 1964. Early work at the Salk Institute and MIT set the stage for his career-long focus on viruses.

At MIT in 1970, he upended a central assumption of molecular biology by independently identified reverse transcriptase, an enzyme that enables RNA viruses to copy their genetic material into DNA. The discovery underpinned modern virology and cancer biology and led to a share of the 1975 Nobel Prize in Physiology or Medicine with Howard Temin and Renato Dulbecco.

Baltimore played major roles as a scientific leader. He was founding director of the Whitehead Institute at MIT beginning in 1982, served as president of Rockefeller University in 1990–'91, and led Caltech from 1997 to 2006. He later served as president and chair of the American Association for the Advancement of Science.

Baltimore also helped shape the ethics of new biology. He was among the organizers of the 1975 Asilomar conference, which established pioneering safety guidelines for recombinant DNA research. Decades later, he continued to weigh in on responsible biotechnology.

His public prominence brought scrutiny. A coauthored 1986 paper became the focus of a long-running scientific-misconduct controversy centered on a collaborator; Baltimore was not found to have committed misconduct, but he resigned the Rockefeller presidency and later returned to MIT. He went on to lead Caltech and remained a central figure in science.

Baltimore's conceptual "Baltimore classification" remains a cornerstone of virology, grouping viruses by how they generate mRNA. The scheme is still taught worldwide and used alongside formal taxonomy.

By Legacy News Staff

(Image: Jason Merritt/Getty Images)