Guide and Seek

On February 7, 1918, American geneticist Ruth Sager was born. An Arts major at the University of Chicago, Sager was so smitten with a required science course she attended that she switched her major to Biology. She followed up with a graduate degree in Plant Physiology and moved to Columbia for doctoral work in genetics where geneticist Barbara McClintock was deep into her future Nobel research.

Sager chose to concentrate on the chloroplast, the organelle or specialized sub-cellular structure responsible for photosynthesis found in green plant cells. Before Sager’s entry into the field, the prevailing view was that the nucleus of the cell contained all the genetic information.

At the Rockefeller Institute, Sager investigated the hereditary traits of cells, attempting to learn where genetic material was actually stored within the cells. She discovered that important pieces of genetic material resided not only within but also outside the cell’s nucleus. She located this genetic material in the respiratory organelles of both animal and plant cells, and in the chloroplasts of plant cells.

Sager recognized early on in her research she would need many series of cells to trace the characteristics she sought and followed them through in an algal species she could control. She demonstrated that, within chloroplasts, all the genes in offspring can originate from only one parent. Further, Sager showed that the one parent or uniparental genetic system exists alongside the nuclear genetic system.

She next turned her attention from chloroplasts to cancer cells and began a second research career when she was invited to join the Department of Microbiology and Molecular Genetics at the Harvard Medical School. At its laboratory, the Dana-Farber Cancer Institute, Sager established the Cancer Genetics Division and served as its Chief. Here she investigated the role of different genetic pieces within a cell that contribute to converting a normal cell into a cancer cell, and cellular materials within a cell that suppress tumour growth. Sager had a keen eye for promising applicants and many of the young scientists she recruited for the division’s staff have become prominent in the field of genetics.

Honours Sager received include the Gilbert Morgan Smith Medal from the National Academy of Science, awarded every three years, and an Outstanding Investigator Award from the National Cancer Institute. The Boston Cancer Research Association’s Ruth Sager Memorial Lecture is given each year by a leading Cancer Researcher to honour her.


B Bondar / Real World Content Advantage


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