Esther Lederberg, PhD, was an American microbiologist and a pioneer of bacterial genetics. In 1950 while working on her doctorate at the University of Wisconsin–Madison, she discovered the bacterial virus lambda phage, which is now a key tool in molecular biology. Her work with the lambda phage led her to the discovery of the plasmid named bacterial fertility factor (F), which plays a key role in bacterial conjugation. Working alongside her husband, Nobel laureate Joshua Lederberg, she helped develop key methods for studying bacterial heredity, including the replica plating technique, which demonstrated that bacterial mutations occur spontaneously rather than as a response to the environment. Despite her contributions, Lederberg struggled for professional recognition, and her work was often overlooked in favor of her male collaborators.
