Evelyn M. Witkin

Research Before DNA was definitively identified as hereditary material, Witkin began to study central problems in genetics involving the duplication of genes and the mechanisms by which genetic changes propagate. When Witkin began her research, it was assumed that agents such as UV directly caused mutations that were responsible for developing resistance. Witkin and others discovered out that the bacteria actively responded to DNA damage in a variety of ways. Through these protective activities, bacteria were themselves shaping the genetic changes that occurred in responses to DNA damage. She also noted that there were differences in the strain's behavior compared to wild strains: the resistant strains did not display a delay before cell division and the development of elongated and filamentous strands, both of which were seen in UV-sensitive strains. Witkin concluded that MFD occurs as a result of rapid enzymatic repair before replication in cases where protein synthesis is inhibited or delayed. In the case of potentially mutagenic UV photoproducts (lesions), a failure to replicate is lethal to the bacterium. If another DNA polymerase is able to copy past an area of damage, the bacterium survives, but with a higher likelihood of errors having occurred during the DNA synthesis and repair. Witkin looked for evidence for a common control mechanism to underlie and explain the variety of cellular responses that she had observed in her work with UV mutagenesis in bacteria. She proposed that UV-damaged DNA generates a regulatory signal that activates a large number of genes. Her findings supported the idea of a control mechanism involving lexA, which normally represses SOS response genes, and recA, which eliminates lexA repression in response to DNA damage. Later, by characterizing the phenotypes of mutagenised E. coli, she and Radman detailed the SOS response to UV radiation in bacteria. Witkin continued to work on the mechanism of the SOS response until her retirement. a Fellow of the American Association for the Advancement of Science (1980); and a Fellow of the American Academy of Microbiology. She was awarded the 2000 Thomas Hunt Morgan Medal and her contributions to science have been recognized by the United States government as she was awarded the National Medal of Science in 2002: For her insightful and pioneering investigations on the genetics of DNA mutagenesis and DNA repair that have increased our understanding of processes as varied as evolution and the development of cancer.

In 2015, she was awarded The Wiley Prize in Biomedical Sciences and was named as one of The Forward 50. Also in 2015, Witkin won the Lasker Award for Basic Medical Research, with Stephen J. Elledge,

In 2021, Rutgers University and the Waksman Institute of Microbiology held "Symposium Celebrating 100th Birthday and Research Accomplishments of Dr. Evelyn M. Witkin", a public symposium and dedication ceremony of a new research laboratory named after her. Kenneth Irvine, interim director of the Waksman Institute, said, "The laboratory is being named after Dr. Witkin because she was an outstanding scientist. But certainly it's important to note that she was a pioneering woman scientist, working at a time when science was dominated by men."

Witkin died of complications from a fall in Plainsboro Township, New Jersey, on July 8, 2023, at the age of 102.

Selected publications