Following residency, Bowman served as chair of pathology at Provident Hospital in Chicago. He was drafted again and spent 1953 to 1955 as chief of pathology for the Medical Nutrition Laboratory at
Fitzsimons Army Hospital in Aurora, Colorado. After leaving the military he moved overseas. "My wife and I decided that we were not going to go back to anything that smacked of segregation," he recalled. He became chair of pathology at Nemazee Hospital in
Shiraz, Iran. "We were recently married, so we took a chance," he said. "It changed our lives completely." Their daughter, Valerie, was born in Iran. In Iran, Bowman saw many diseases for the first time. "I saw smallpox, brucellosis, rabies, all sorts of things," he said. One of the most common diseases among certain ethnic groups in Iran was
glucose-6-phosphate dehydrogenase deficiency favism, an
Inborn error of metabolism metabolic disease caused by an enzyme deficiency in red blood cells. The mutation, which is the most common human enzyme defect, renders those who have it unable to break down a toxin found in fava beans. This led to a series of important discoveries about the genetics of inherited blood diseases and the populations they affect, especially in the Middle East, Africa and America. It enabled him to travel all over the world collecting blood samples for DNA testing. It also led to frequent contacts and collaborations with
University of Chicago researchers, who had first described the enzyme deficiency (glucose-6-phosphate dehydrogenase deficiency, or G6PD) and its connection with
antimalarial medications. Bowman joined the faculty of the University of Chicago in 1962 as assistant professor of medicine and pathology and director of the hospital's blood bank. He was promoted to full professor and director of laboratories in 1971. From 1973 to 1984, he directed the university's Comprehensive Sickle Cell Center, funded by the National Institutes of Health. He was a member of the national advisory group that urged the Nixon administration to initiate the inception of the Comprehensive Sickle Cell Center, which served as a model of patient-centered disease management and research. He also served as assistant dean of students for minority affairs for the Pritzker School of Medicine from 1986 to 1990. In 1972, Bowman stated that mandatory sickle cell screening laws were "more harmful than beneficial." These laws could "revive many of the past misadventures and racism of eugenics movements," he argued at the time, adding that adult screening programs create "inaccurate, misleading, politically motivated propaganda which has left mothers frantic." In 1973, he was named to two federal review committees designed to oversee sickle cell screening and education and to evaluate laboratory diagnostic techniques. He was the first tenured
African-American professor in the University of Chicago's Biological Sciences Division.{{cite web|accessdate=December 25, 2016 == Personal life ==