Rowley, Janet (1925-) is an American geneticist, a scientist who investigates the structure, function, and transmission of genes. A gene is the part of a cell that determines which characteristics living things inherit from their parents. Rowley has done important research that has contributed to a greater understanding of the disease leukemia, a kind of cancer in which white blood cells multiply in an uncontrolled manner.

Rowley was born Janet Davison on April 5, 1925, in New York City. She was the only child of Hurford and Ethel Davison, who were teachers. They encouraged their daughter to do well in school, where she developed an early interest in science. In 1940, Davison received a scholarship for a special four-year program at the University of Chicago in which she completed the equivalent of her last two years of high school and first two years of college. Upon completion of the program in 1944, she received a bachelor of philosophy degree. She continued her education at the University of Chicago, earning a bachelor of science degree in 1946 and a medical degree in 1948.

On December 18, 1948, Davison married Donald Rowley, a classmate from medical school. Janet Rowley worked as a research assistant at the University of Chicago from 1949 to 1950. From 1950 to 1951, she was an intern at the Marine Hospital of the U.S. Public Health Service in Chicago. The Rowleys' first son. Donald Jr., was born in 1952. The family then moved to Maryland, where from 1953 to 1954, Janet Rowley worked part time in the Infant Welfare and Prenatal Clinics operated by the Montgomery County Department of Health. A second son, David, was born in 1954.

The Rowleys returned to Chicago in 1955. Janet Rowley was a Levinson Foundation research fellow at Cook County Hospital from 1955 to 1961. From 1957 to 1961, she also worked as a clinical instructor of neurology at the University of Illinois School of Medicine in Chicago. The Rowleys' third son. Robert, was born in 1960.

Donald Rowley, who had become an immunologist, took a sabbatical leave in England from 1961 to 1962. The family accompanied him, and Janet Rowley obtained a position as a trainee at the Radiology Laboratory at Churchill Hospital in Oxford. Upon their return to Chicago in 1962, Janet Rowley became a research associate at the University of Chicago Medical School and at the university's Argonne Cancer Research Hospital (now known as the Franklin McLean Memorial Research Institute). The last of the Rowley children, Roger, was born in 1963. Janet Rowley was promoted to associate professor in 1969. During another of her husband's sabbaticals, from 1970 to 1971, she also took a leave of absence and again worked at the laboratory in Oxford.

Rowley began to study the chromosomes, the parts of a human cell that contain the genes, of leukemia patients at the University of Chicago in the 1960's and 1970's. Human chromosomes are arranged in pairs. They become visible under a microscope if they are stained and magnified just as the cell that contains them is about to divide. Rowley worked with a special microscope and used the staining technique called chromosome banding, in which staining the chromosomes with fluorescent chemicals (chemicals that give off light) creates visible bands of 23 chromosome pairs. Each pair has its own distinctive pattern.

Rowley found that in patients suffering from chronic myeloid leukemia (CML), which occurs primarily in adults, sections of two of the chromosomes had switched places, or translocated. Such an abnormality of the chromosomes is called a translocation. By 1973, Rowley had shown that specific translocations are associated with specific cancers. This finding provided proof for the scientific theory that when growth-controlling genes translocate, the chemical instructions that control cell division become damaged and cells multiply without control, leading to cancer. Rowley reported her research in many scientific journals and wrote the book Chromosome Changes in Leukemia, published in 1978.

In 1977, Rowley was promoted to full professor at the University of Chicago. She became Blum-Riese Distinguished Service professor at the university's Department of Medicine and Department of Molecular Genetics and Cell Biology in 1984. That year she also was elected to membership in the National Academy of Sciences. She served as president of the American Society of Human Genetics in 1993.

Rowley has won many awards and honors, including the National Medal of Science and the Lasker Award for Clinical Science, both of which she received in 1998. She is cofounder and co-editor of the scientific journal Genes, Chromosomes and Cancer.