Boris Ephrussi

Boris Ephrussi was born on May 9, 1901 and died on May 2, 1979. He was a French geneticist of Russian origin. He was one of the many famous Jewish life scientists. He had published two papers in November 1966 which represented a key step in a decade of research in the laboratories of Boris Ephrussi. This research helped transform mammalian genetics, especially human genetics.

Boris started his scientific training as a russian emigre in 1920. He studied the initiation and regulation of embryological processes by intracellular and extracellular factors. A major strand of his early research concerned the effect of temperature on the development of fertilized sea urchin eggs. In this work he used a micromanipulator, which was developed by Robert Chambers who was an American Biologist.

At the time a second dissertation was standard in France and he conducted a project on tissue culture (see EPHRUSSI 1935a). Ephrussi ran into difficulties which were assocaiated with early unsatisfactory tissue culture techniques. Despite the difficulties Ephrussi concluded from studies of brachyury in mice, that intrinsic factors (i.e genes) play a key role in development.

The next phase of his career, Ephrussi coupled his embryological concerns to a firm conviction that one must understand the role of genes in order to decipher embryological processes.He moved to Caltech in 1934-1935 to learn genetics within the intellectual empire of T.H. MORGAN.This move was supported by the Rockefeller Foundation Fellowship.At this period he had done important work with GEORGE BEADLE, who joined him in Paris in the fall of 1935. There results on Experiments with Drosophila eye transplants was fundamental to the work of BEADLE and TATUM who were working with Neurospora and from this research developed the "one gene-one enzyme" hypothesis.

During World War Two, Ephrussi spent most of his time as a refugee at John Hopkins University.After which he began work in France on Yeast and cytoplasmic genetics. He began working at the [Institut de Biologie Physicochimique] (the Institute Rothschild in Paris), and later at the CNRS at Gif-sur-Yvette, where he studied the contribution of the cytoplasm to the cell phenotype and pursued the interactions between nuclear and cytoplasmic genetic endowments needed to yield an intact, functioning (albeit single-celled) organism.

Ephrussi continued to work on the topics in which he was primarily interested into the late 1970s. Topics which he covered were,

• using hybrids with teratomas to explore determination and differentiation (e.g. FINCH and EPHRUSSI 1967; KAHAN and EPHRUSSI 1970).
• negative regulation of differentiated function (e.g., DAVIDSON, EPHRUSSI and YAMAMOTO 1966; FOUGBRE, RUIZ and EPHRUSSI 1972).
• cellular and genetic approaches over a direct attack at the molecular level (EPHRUSSI 1970, p. 12).

In 1975 Ephrussi won a Louisa Gross Horwitz Prize and he lived long enough to recongnize that the transformation of transplantation into a genetic tool would take on a new and more powerful aspect in the molecular era. He died not seeing the genetic advances made by DNA recombination studies which were set in motion by the studies in had undertaken. It can be said that Ephrussi was a fundamental leader of embryology and a main contributor to the reunion of modern genetics and Embryology.