BY ARTHUR B.PARDEE

RUTH SAGER HAD TWO distinguished careers. In the first she was a leading exponent of organelle, non-nuclear genetics; in the second she was a major innovator in cancer genetics, proposing, discovering, and investigating roles of tumor suppressor genes. At the pinnacle of research on the problem of non-nuclear or cytoplasmic genetics for many years, she almost single-handedly developed this subject of non-Mendelian, cytoplasmic genetics (“A vast, unexplored region of genetics was opened here today” [1963]). The very existence of hereditary determinants other than nuclear genes was doubted by a large part of the scientific community, although it was proposed in 1908 from observations on higher plants. Sager gathered data and argued in support of a second genetic system in the face of great skepticism and finally made this a respectable and exciting major area of genetics.

During her final 25 years she transferred her efforts to the genetics of cancer. Among her outstanding contributions, she devised the first cell lines and culture medium capable of culturing and comparing normal and cancer cells. She emphasized the major role of chromosome rearrangements and the accelerated evolution of cancer cells and the