HARRIETI' EP?XWSSI-TAYLOR

April 10,1918-March 30,1968

The death of Harriett Ephrussi-Taylor, coming at the height of her scientific creativity,
shocked and saddened her many colleagues, students and friends in France, the United States,
and indeed throughout the world. Having returned several months earlier from a five-year
leave in the United States as Professor of Biology in Case Western Reserve University, Harriett
Ephrussi-Taylor was in the midst of reorganizing her laboratory at the Germ-e NationaI de la
Recherche Scientifique in Gif-stir-Yvette, France. Her brief but devastating illness prevented
the fuliillment of these plans.

  Harriett Taylor was born on April 10, 1918 in Belmar, New Jersey, completed her secondary
school education in Washington, DC., and then pursued her undergraduate studies in Radcliffe
College, Cambridge, Massachusetts. The daughter of a distinguished scientist who had helped de-
velop radar systems of detection Harriett Taylor soon became interested in science herself. After
receiving her A.B. from Radcliffe cum laude in 1Q3S1 she undertook graduate study in zoology,
receiving the M.A. from the University of California in Los Angeles in 1942 and then the Ph.D.
from Columbia University in 1945.

  As a doctoral candidate, Harriett's interests focussed on a field of genetics which was about
to blossom, that of the molecular genetics of microorganisms. A student of Professor Leslie C.
Dunn, Harriett investigated the genetic and physiological basis of the lag period in the growth
of yeast cultures. While engaged in her studies, she read the now classic paper of Avery, Mac-
Lead and McCarty shortly after its publication in 1944. Realizing the immense importance of
this paper to the future of genetics, and despite the cautious advice of her teachers that the phe-
nomenon of bacterial transformation might prove to be an isolated case ~app~~ble to the main-
stream of genetic research, Harriett Taylor went to see Oswald Avery, who agreed to accept her
as a post-doctoral investigator in his laboratory at the then Rockefeller Institute for Medical Re-
search. The period at Rockefeller from 1945 to t947 proved to be extremely valuable, for she
started at that time to sketch the outlines of her subsequent research on the tine structure of
transfomhg DNA. She began to collect various mutants of pneumococcus deficient in their
capacity to synthesize capsular polysaccharide. Subsequent investigations with them were to
prove the allelism between factors in transforming DNA and factors in the genome of the re-
cipient bacterium as well as the sub-divisibility of the transforming agent into independentfy
mutable and recombinable sites.

Harriett Taylor met Boris Ephrussi in the summer of 1946 during the historicaUy significant
symposium on Heredity and Variation in Microorganisms held at Cold Spring Harbor. She left
Rockefeller in 1947 to work in Ephrussi's laboratory on Rue Pierre Curie in Paris. They were
married in 1949, and a daughter, Anne, was born to them some years later. In 1952 the Labora-
toire de g&&ique physiologique was moved to Gif-sur-Yvette, where the Bphrussis lived and
worked ever since, except for their sojum in Cleveland from 1962 to 1967.

Dutiful and happy in her demanding roles as wife, mother and housekeeper, Harriett
Ephrussi-Taylor organized her complex life in such a fashion that she could continue a vigomu~,
full-time program of research which included the tmining and supervision of a large number of
students and collaborators who came from many countries to work with her. Together tbey per-
fected quantitative methods for the study of genetic transformation, revealed stages in the process
of transformation and characterized them., exploited physical techniques for demonstrating the
dependence of transformation on the size of transforming DNA and for partially separating
genetically distinct fragments of DNA, and showed that mutations could be chemically induced
in DNA in vitro.

She had embarked upon an analysis of the recombination stage of transformation at which
donor material is inserted into the genome of the recipient bacterium, and the findings obtained
in her laboratory led her to propose a model of the molecular mechanism of recombination which
further studies were intended to test. She cannot complete the experiments she was planning, but
the many whom she inspired through her teaching and publications will carry on to pursue the
problems she formulated and to extend the field of research she helped to initiate.