- Born:
- March 7, 1938, New York, New York, U.S.
- Died:
- September 6, 2025, Woods Hole, Massachusetts (aged 87)
- Awards And Honors:
- Nobel Prize (1975)
- Subjects Of Study:
- cancer
- oncogenic virus
- retrovirus
- reverse transcriptase
- transcription
David Baltimore
-
Who is David Baltimore?
David Baltimore (1938–2025) was an American virologist who shared the 1975 Nobel Prize in Physiology or Medicine with Howard M. Temin and Renato Dulbecco.
Working independently, Baltimore and Temin discovered reverse transcriptase, an enzyme that synthesizes DNA from RNA. Baltimore also researched the interactions between viruses and a cell's genetic material. The research of all three scientists contributed to understanding the role of viruses in the development of cancer.
Baltimore received a B.A. in chemistry from Swarthmore College in 1960 and a doctorate from the Rockefeller Institute in 1964. In 1968, Baltimore joined the faculty of MIT. He later became director of the Whitehead Institute for Biomedical Research in 1983, president of Rockefeller University in 1990, and president of the California Institute of Technology from 1997 to 2006.
1 Britannica SourceCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
What is a virologist?
A virologist is a scientist who studies viruses, which are causative agents of many diseases. Virology is a branch of microbiology that deals with the study of viruses.
David Baltimore (1938-2025) was an American virologist who shared the Nobel Prize for Physiology or Medicine in 1975 with Howard M. Temin and Renato Dulbecco for discovering reverse transcriptase, an enzyme that synthesizes DNA from RNA. His research led to understanding the interaction between viruses and the genetic material of the cell and the role of viruses in the development of cancer.
3 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
What is reverse transcriptase, and why was its discovery important?
Reverse transcriptase is an enzyme that retroviruses encode from their genetic material to catalyze the transcription of the retrovirus's RNA into DNA. David Baltimore, along with Howard M. Temin, independently discovered reverse transcriptase in 1970.
This discovery was important because it demonstrated that genetic information could flow from RNA to DNA, which was an exception to the central dogma of genetic theory. Their work allowed for the identification of a unique virus family (Retroviridae) and spurred the understanding of the pathogenesis of these viruses and a rush to discover other infectious cancer-causing agents. Reverse transcriptase has also become an invaluable tool in recombinant DNA technology and is a fundamental component of the reverse transcription-polymerase chain reaction (RT-PCR) used in research and disease diagnosis. For this work, Baltimore and Temin, along with their mentor Renato Dulbecco, were awarded the Nobel Prize in Physiology or Medicine in 1975.
3 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How did David Baltimore's work contribute to our understanding of viruses like HIV?
David Baltimore, along with Howard Temin, discovered reverse transcriptase, an enzyme that synthesizes DNA from RNA, which was crucial in understanding retroviruses like HIV. This discovery, made independently by Baltimore and Temin, demonstrated that RNA viruses contain the blueprint for reverse transcriptase, enabling them to copy DNA from an RNA template. The viral DNA integrates into the host cell, potentially transforming it into a cancer cell. Drugs that inhibit reverse transcriptase were the first treatments available to people living with HIV. For this groundbreaking work, Baltimore shared the Nobel Prize in Physiology or Medicine in 1975 with Temin and Renato Dulbecco.
2 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
What awards and positions has David Baltimore held in scientific research?
David Baltimore (1938–2025) was an American virologist who shared the 1975 Nobel Prize for Physiology or Medicine with Howard M. Temin and Renato Dulbecco. His work led to the discovery of reverse transcriptase, an enzyme that synthesizes DNA from RNA, and to understanding the interactions between viruses and a cell's genetic material. Baltimore was director of the Whitehead Institute for Biomedical Research in 1983, president of Rockefeller University in 1990, and president of the California Institute of Technology from 1997 to 2006. In 2006, he was elected president of the American Association for the Advancement of Science (AAAS).
1 Britannica SourceCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
David Baltimore (born March 7, 1938, New York, New York, U.S.—died September 6, 2025, Woods Hole, Massachusetts) was an American virologist who shared the Nobel Prize for Physiology or Medicine in 1975 with Howard M. Temin and Renato Dulbecco. Working independently, Baltimore and Temin discovered reverse transcriptase, an enzyme that synthesizes DNA from RNA. Baltimore also conducted research that led to an understanding of the interaction between viruses and the genetic material of the cell. The research of all three men contributed to an understanding of the role of viruses in the development of cancer.
Baltimore and Temin both studied the process by which certain tumour-causing RNA viruses (those whose genetic material is composed of RNA) replicate after they infect a cell. They simultaneously demonstrated that these RNA viruses, now called retroviruses, contain the blueprint for an unusual enzyme—a polymerase called reverse transcriptase—that copies DNA from an RNA template. The newly formed viral DNA then integrates into the infected host cell, an event that can transform the infected cell into a cancer cell.
Baltimore received an undergraduate degree in chemistry from Swarthmore College, Pennsylvania (B.A., 1960), and went on to study animal virology at the Rockefeller Institute (now Rockefeller University) in New York City, where he obtained a doctorate in 1964, and at the Massachusetts Institute of Technology (MIT) in Boston. He worked with Dulbecco at the Salk Institute in La Jolla, California (1965–68), studying the mechanism of replication of the poliovirus.
Baltimore joined the faculty of MIT in 1968, accompanied by Alice Huang, a postdoctoral fellow who had worked on vesicular stomatitus virus (VSV) at the Salk Institute. In Boston, Baltimore and Huang, who had married, showed that VSV, an RNA virus, reproduced itself by means of an unusual enzyme (an RNA-dependent RNA polymerase) that copies RNA by a process not involving DNA.
Baltimore then turned his attention to two RNA tumour viruses—Rauscher murine leukemia virus and Rous sarcoma virus—to discover whether a similar enzyme was at work in their replication. It was through these experiments that he discovered reverse transcriptase. This discovery proved an exception to the “central dogma” of genetic theory, which states that the information encoded in genes always flows unidirectionally from DNA to RNA (and thence to proteins) and cannot be reversed. Since its discovery, reverse transcriptase has become an invaluable tool in recombinant DNA technology.
Baltimore became director of the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts, in 1983 and in 1990 left to become president of Rockefeller University. In 1989 he figured prominently in a public dispute over a 1986 paper published in the journal Cell that he had coauthored while still at MIT. The coauthor of the article, Thereza Imanishi-Kari, was accused of falsifying data published in the paper. Baltimore, who was not included in charges of misconduct, stood behind Imanishi-Kari, although he did retract the article. Because of his involvement in the case, however, he was asked to resign as president of Rockefeller University, and in 1994 he returned to MIT. In 1996 a U.S. government panel cleared Imanishi-Kari of the charges of scientific misconduct. The case was analyzed in The Baltimore Case (1998) by Daniel Kevles.
Baltimore was president of the California Institute of Technology from 1997 to 2006, when he was elected to a three-year term as president of the American Association for the Advancement of Science (AAAS). Among his other appointments, he served as a member of the Encyclopædia Britannica Editorial Board of Advisors.
The trusted destination for professionals, college students, and lifelong learners.
SUBSCRIBE
