Janet Mertz Collection

Janet E. Mertz, born 1949, is an American biochemist, molecular biologist, and cancer researcher. She earned her undergraduate degree in 1970 from the Massachusetts Institute of Technology and joined the biochemistry department at Stanford University in September of that same year, working with her doctoral advisor Paul Berg in his lab. Initially, the Berg lab focused on work related to gene cloning techniques, and Mertz was assigned the project of figuring out how to replicate and express recombinant DNAs in E. coli bacteria. However, after concerns were raised by Richard Pollack at a course taught at Cold Spring Harbor Laboratory, Berg imposed a moratorium on experiments in his lab related to potentially cloning any oncogenes (e.g. from SV40) until the safety concerns had been addressed.

In the interim, Mertz focused on other projects related to the development of recombinant DNA techniques, including the examination of the infectivity of different forms of SV40 DNA in primate cells. Mertz discovered that DNA ends generated by cutting with the EcoRI restriction enzyme are “sticky,” permitting any two such DNAs to be readily recombined. Using this technique, in June 1972 she created the first recombinant DNA that could have been cloned in bacteria. Unable to proceed further with the discovery due to the moratorium, Mertz’s Ph.D. thesis centered around developing other ways to create, select, and grow mutants of SV40. Paul Berg received the 1980 Nobel Prize in Chemistry in part for the discoveries Mertz made under his mentorship.

Mertz joined the McArdle Laboratory for Cancer Research at the University of Wisconsin-Madison in December 1976, where she is current a Professor of Oncology.