Esther Zimmer Lederberg, the Mother of Bacterial Genetics


Esther Zimmer 1946
This portrait reminds me of another Bronx contemporary, Betty Joan Perske (professional name Lauren Bacall). Esther’s evocative gaze suggests the confidence and determination to succeed in the male-dominated world of scientific research.


Esther Zimmer Lederberg (born December 16, 1922, died November 11, 2006) was the largely unknown “mother of bacterial genetics.” She and her famous husband, Joshua Lederberg, collaborated during the decade leading up to the discovery of the double helix and the beginning of molecular biology. Joshua won the Nobel Prize in 1958, along with two of Esther’s mentors, George Beadle and Edward Tatum. Esther’s contributions were overlooked by the Nobel committee.

EstherMZimmerLederberg lab 1950s
Esther Lederberg in the UW Madison laboratory


One of the classic texts on the history of genetics is Thomas D. Brock’s The Emergence of Bacterial Genetics. In his chronology of the field, Brock lists 130 scientists who made significant discoveries between 1865 (Gregor Mendel) and 1975 (Paul Berg and the Recombinant DNA Moratorium): 126 men and 4 women. Brock listed several scientists more than once; Esther Lederberg was the only woman recognized for more than one discovery: Lambda phage, replica plating, F-factor, and specialized transduction. Although Brock does not call Esther “the mother of bacterial genetics,” he does give her more credit for more scientific achievements than any other woman in the history of bacterial genetics.

Esther Lederberg is certainly not the first female scientist whose contributions were undervalued or misrepresented. Social scientists actually have a term for the this common phenomenom, the Matilda effect. 


Matilda Joslyn Gage, born 24 March 1826; died 18 March 1898 abolitionist, suffragette, author of “Woman as Inventor” (1870).



Matilda Joyce Gage,  published , Woman as Inventor attempting to correct the historical record of important inventions, such as the cotton gin.  Gage wrote in 1870, “The most remarkable invention of the age, in its industrial, social, and political influence,–the cotton gin,–owes its orign to a woman, Catharine Littlefield Green, widow of General Greene, of Revolutionary memory, with whom the idea originiated.” Most historians concur with Gage’s reattribution, but every student still learns about Eli Whitney, the legendary inventor of the cotton gin; and none of the history textbooks tell Catherine Green’s side of the story.

Margaret Rossiter who coined the term, Matilda Effect, explained, “Since this systematic bias in scientific information and recognition practices fits the second half of Matthew 13:12 in the Bible, which refers to the under-recognition accorded to those who have little to start with, it is suggested that sociologists of science and knowledge can add to the Matthew Effect, made famous by Robert K. Merton in 1968, the Matilda Effect, named for the American suffragist and feminist critic, Matilda J. Gage of New York, who in the nineteenth century both experienced and articulated this phenomenon.”

In Esther Lederberg’s case, her brilliant husband, Joshua Lederberg, was so famous and impressive that colleagues, textbooks, and historians attribute her achievements to him, or, at best, refer to the specific discovery as the Lederbergs. Implicit is the assumption that Esther Lederberg was merely “his hands”, but the male genius, Joshua, was the “brains” of the collaboration.

However, a closer consideration of the historical development of the correct interpretation of how bacterial sex occurs, reveals that Joshua Lederberg was wrong, and stubbornly persisted in holding onto his wrong idea of bacterial conjugation. The correct interpretation of the exotic process of bacterial sex–that the male only transfers some genes to the female in a uni-directional manner, rather than a mutual exchange of genes, was finally demonstrated by the French investigators, Wollman and Jacob, in 1955.



Brock, T. D. 1990. The Emergence of Bacterial Genetics. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY.

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