Evelyn M. Witkin (née Maisel; March 9, 1921 – July 8, 2023) was an American bacterial geneticist at Cold Spring Harbor Laboratory (1944–1955), SUNY Downstate Medical Center (1955–1971), and Rutgers University (1971–1991).

[2][6][7] In 2015, Witkin received the Albert Lasker Award for Basic Medical Research "for discoveries concerning the DNA-damage response - a fundamental mechanism that protects the genomes of all living organisms.

When Witkin began her research, it was assumed that agents such as UV directly caused mutations that were responsible for developing resistance.

[19][4] During her first summer as a student at Cold Spring Harbor, Witkin worked with bacteria, which had recently been identified as having genes and being capable of viral resistance.

Given that there were no published survival curves for the mutation of E. coli using ultraviolet light (UV), Witkin initially chose doses that turned out to be quite high.

She observed a decrease in damage-induced suppressor mutations when protein synthesis was transiently inhibited as a result of UV irradiation.

[21] Witkin concluded that MFD occurs as a result of rapid enzymatic repair before replication in cases where protein synthesis is inhibited or delayed.

[13] It was later determined that this type of excision repair is mediated in bacteria by a transcription-repair coupling factor (TRCF), which is produced by the MFD gene.

[13][11][20] In 1970, Miroslav Radman, a recent graduate of the Free University of Brussels, circulated a memorandum to Witkin in which he proposed a model for "SOS replication".

[11] He theorized that sudden and extensive DNA damage could trigger an inducible stress response, genetically controlled and involving synthesis of new proteins.

[24][25] 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 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:[30] 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.

[32] Also in 2015, Witkin won the Lasker Award for Basic Medical Research, with Stephen J. Elledge,[12] "for discoveries concerning the DNA-damage response - a fundamental mechanism that protects the genomes of all living organisms.