 In early 1941 , she took a leave of absence from Missouri in hopes of finding a position elsewhere . She accepted a visiting Professorship at Columbia University , where her former Cornell colleague Marcus Rhoades was a professor . Rhoades also offered to share his research field at Cold Spring Harbor on Long Island . In December 1941 , she was offered a research position by Milislav Demerec , the newly appointed acting director of the Carnegie Institution of Washington 's Department of Genetics Cold Spring Harbor Laboratory ; McClintock accepted his invitation despite her qualms and became a permanent member of the faculty . 
