by Gidon Schwartz, Education & Outreach Executive
Microbiology is the study of microorganisms, tiny life forms that quietly shape almost every part of our world. It is central to medicine, vaccine development, infection control, agriculture, food production, and even our own digestive health. During the Covid-19 pandemic, microbiologists worked urgently to understand the virus’s structure so that vaccines and public health measures could be developed. Yet microbes are also part of ordinary life, helping to produce cheese, bread and fermented foods, supporting soil health, and sustaining the delicate bacterial balance within our gut. Much of what we know about bacteria, and the viruses that infect them, stems from the quiet curiosity and determination of scientists like Esther Lederberg, a pioneer whose work transformed genetics and microbiology even as the world often overlooked her.
Esther Lederberg (née Zimmer) was born in 1922 in New York to Pauline Geller Zimmer and David Zimmer, a Romanian immigrant who ran a print shop. Her early exposure to printing presses would later inspire one of her most important scientific innovations. While others saw only machinery, Esther saw a method. She used that childhood familiarity to develop replica plating, a clever technique that allowed her to “print” bacterial colonies from one plate to another using sterile fabric. It was a simple, elegant solution born from curiosity, and it enabled her to show that genetic traits do not change in response to the environment, overturning assumptions rooted in Lamarckian thinking that had endured since 1809. This technique is so fundamental, it is routinely used to this day.
Esther’s determination to pursue science emerged early. She graduated high school at fifteen and enrolled in biochemistry at Hunter College despite teachers insisting that science was not a career for women. Undeterred, she excelled, later earning a bachelor’s degree in genetics while working as a research assistant on Neurospora crassa, a mould that infects plants. She followed her interests to Stanford University, completing a master’s degree focused on the same organism. Each step in her education was guided not by encouragement or institutional support, but by her own drive to understand how life works at its smallest scales.
In 1946, Esther married Joshua Lederberg, a young scientist at Yale University. They later moved to the University of Wisconsin, where Joshua became a professor and Esther pursued her PhD. Her research explored how Escherichia coli bacteria mutate and adapt, leading to discoveries that reshaped modern genetics. She identified the lambda phage, a virus that infects bacterial cells, and discovered F plasmids, which enable bacteria to transfer genetic material between cells. These findings revolutionised the study of bacterial evolution, adaptation, and gene exchange – the very discovery that allows genetic modification and gene therapy which are at the forefront of modern research. Each breakthrough began the same way: with a subtle question, followed by careful observation and persistent investigation. Her curiosity drove the science forward long before anyone recognised how significant her contributions would become.
Despite her achievements, the world often refused to give Esther proper credit. In 1956, she shared the Pasteur Award with her husband, but the recognition she received never matched the scale of her contributions. When Joshua won the Eli Lilly Award in 1953, he told reporters that Esther should have been included. In 1958, he won the Nobel Prize in Physiology or Medicine alongside George Beadle and Edward Tatum. Esther’s discoveries were foundational to the research that led to the prize, yet she was not named and became known simply as the Nobel laureate’s wife. Though Joshua acknowledged her in his Nobel lecture, their return to Stanford brought further inequity. He was appointed head of the genetics department, while she was offered only a research associate position in another department. Years later, she finally received a faculty role, but without tenure, a rank that did not reflect her expertise or impact. She accepted the position and continued her scientific work until her retirement in 1985, driven by the same quiet determination that had guided her since childhood.
Beyond science, Esther loved early music and played medieval, Renaissance and baroque pieces on original instruments. She founded a recorder orchestra in 1962 and devoted time to reading Dickens and Austen, attending society meetings to study their works.
Esther Lederberg’s story is a powerful reminder that scientific revolutions do not always come from loud voices or celebrated names. Sometimes they come from a scientist who simply keeps asking questions, keeps looking closely and keeps working, even when recognition does not follow. Her quiet curiosity and unwavering determination changed the course of genetics and microbiology, shaping the field in ways that continue to guide research today. Her legacy shows that science can be transformed by those who persist in the pursuit of understanding, even when the world refuses to give them the credit they deserve.
