Modrich is the James B. Duke Professor of Biochemistry at Duke University Medical Center. His research clarified the nature and functions of DNA mismatch repair, which plays an important role in the control of mutation production. During the course of their work on the human pathway, his laboratory demonstrated that cancer cells characterized by microsatellite instability are defective in mismatch repair and resistant to the action of certain chemotherapeutic drugs.
He is recipient of the 2015 Nobel Prize in Chemistry and a member of the National Academy of Sciences, the National Academy of Medicine and the American Academy of Arts and Sciences. Modrich received his B.S. degree in Biology from the Massachusetts Institute of Technology in 1968 and his Ph.D. in Biochemistry from Stanford University in 1973. After a postdoctoral fellowship at Harvard Medical School, he joined the Department of Chemistry, UC Berkeley in 1974 as an Assistant Professor. He was recruited to the Department of Biochemistry at Duke in 1976.
Modrich is an alumnus of the 1964 Science Talent Search and the 1964 International Science and Engineering Fair.