Modrich was born on June 13, 1946, in
Raton, New Mexico to Laurence Modrich and Margaret McTurk. He has a younger brother Dave. His father was a biology teacher and coach for basketball, football and tennis at
Raton High School where he graduated in 1964. origin. His paternal grandfather, of Croatian descent, is probably from the small village of
Modrići near
Zadar, and grandmother of Montenegrin descent, both immigrated to the United States from coastal
Croatia in the late 19th century. His maternal family is of mixed German and Scotch-Irish descent. Modrich obtained a
B.S. degree from the
Massachusetts Institute of Technology in 1968 and subsequently a
Ph.D. degree from
Stanford University in 1973. He continued his research as a postdoc in the lab of
Charles C. Richardson at
Harvard Medical School for a year (1973–1974). ==Research==