Ruth Sager (February 7, 1918 – March 29, 1997) was an American plant geneticist, cell physiologist and cancer researcher.

[5][6] Aiming to give their three daughters a wide-ranging education, Sager’s parents took them on a trip through Europe and the Middle East from February to May 1938.

Over the next few years, she spent time working on several American training farms of Hashomer Hatzair, a Zionist movement for young secular Jews.

Sager was awarded a Merck Fellowship from the National Research Council in 1949, and worked as a postdoctoral fellow at the Rockefeller Institute on the chloroplast from 1949 to 1951 in the laboratory of Sam Granick.

[10] She was promoted to a staff position (assistant in the biochemistry division) in 1951, working in this capacity until 1955, using the alga Chlamydomonas reinhardtii as a model organism.

[5] This research provided evidence for non-Mendelian uniparental inheritance; it also showed that there are multiple independent genetic systems in Chlamydomonas.

[10] She joined Columbia University's zoology department as a research associate in 1955, supported by funding from the United States Public Health Service and the National Science Foundation.

[11] She was promoted to senior research associate in the early 1960s, but she had difficulty obtaining a faculty position due to initial skepticism surrounding cytoplasmic inheritance from the scientific community, as well as gender discrimination.

[13] For more than half a century she demonstrated vision, insight and determination to develop novel scientific concepts in the face of established dogmas.