Esther Lederberg, 83, a Founder of Bacterial Genetics

Esther Lederberg, who died November 11 at 83, was a microbiologist who made early discoveries about the sex lives of bacteria that continue to be important to researchers today.

In collaboration with her husband, Joshua Lederberg, she discovered processes by which bacteria can exchange genes by way of viruses or, more directly, through conjugation. She also worked on processes by which genes are turned on and off. The discoveries showed that the bacterial genome was far more dynamic than had been thought, and helped form the basis of the new field of bacterial genetics.

Mr. Lederberg went on to win the Nobel Prize for Physiology or Medicine in 1958 for discoveries about how bacteria swap genes; however his wife, who worked under him in the same Stanford University laboratory, was not mentioned in the award.

Born in the Bronx on December 18, 1922, Esther Zimmer attended Hunter College, then earned a master's degree at Stanford in 1946, marrying Joshua Lederberg the same year. She earned her doctorate in 1950 at the University of Wisconsin, where her husband, just 22, had been appointed professor of genetics

It was at Madison at the Lederbergs made seminal discoveries, including a lab technique called replica plating that uses scraps of velvet to literally imprint identical bacterial colonies in Petri dishes. In 1959, in the wake of Joshua Lederberg winning the Nobel Prize, he was appointed chairman of the newly created department of genetics at the Stanford School of Medicine, and Esther Lederberg received an appointment at the department of microbiology and immunology. She was emeritus faculty there at her death.

The Lederbergs were divorced in 1966, and Esther Lederberg went on to remarry. She was director of the Plasmid Reference Center at Stanford for a decade starting in 1976.

Lederberg was intensely involved in the study and practice of Early Music, and formed the Mid-Peninsula Recorder Orchestra in 1962.