Urs Leupold (July 19, 1923 – October 9, 2006) was a Swiss geneticist whose studies of the fission yeast ''

Schizosaccharomyces pombe ''Schizosaccharomyces pombe'', also called "fission yeast", is a species of yeast used in traditional brewing and as a model organism in molecular and cell biology. It is a unicellular eukaryote, whose cells are rod-shaped. Cells typically meas ...

'' were instrumental in establishing this organism as a key model system for eukaryotic cell and molecular biology. Leupold began his studies of ''S. pombe'' in 1946 upon encouragement by

Øjvind Winge Øjvind Winge (19 May 1886 – 5 April 1964) was a Danish biologist and a pioneer in yeast genetics. Education Winge was born in the city of Aarhus in Jutland, the mainland of Denmark. After completing secondary school he travelled to the Univer ...

. In 1947, Leupold determined that a culture of ''S. pombe str. liquefaciens'' contained strains expressing four distinct mating types: ''h''⁴⁰, ''h''⁹⁰, ''h''⁺, and ''h''⁻. Most current ''S. pombe'' laboratory strains are derived from the ''h''⁹⁰, ''h''⁺, and ''h''⁻ strains known as 968, 975, and 972. Leupold went on to carry out postdoctoral studies with

Norman Horowitz Norman Harold Horowitz (March 19, 1915 – June 1, 2005) was an American geneticist at Caltech who achieved national fame as the scientist who devised experiments to determine whether life might exist on Mars. His experiments were carried out by ...

at Caltech and with

Boris Ephrussi Boris Ephrussi (; 9 May 1901 – 2 May 1979), Professor of Genetics at the University of Paris, was a Russo- French geneticist. Ephrussi was born on 9 May 1901 into a Jewish family. His father, Samuel Osipovich Ephrussi, was a chemical engineer; ...

at the University of Paris. Notably, with

, Leupold isolated the first conditional (temperature sensitive) mutations in the bacterium ''

Escherichia coli ''Escherichia coli'' ( )Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Escherichia'' that is commonly fo ...

'' as part of an effort to address criticisms raised by

Max Delbrück Max Ludwig Henning Delbrück (; September 4, 1906 – March 9, 1981) was a German–American biophysicist who participated in launching the molecular biology research program in the late 1930s. He stimulated physical science, physical scientist ...

of the

one gene-one enzyme hypothesis 1 (one, unit, unity) is a number, numeral, and glyph. It is the first and smallest positive integer of the infinite sequence of natural numbers. This fundamental property has led to its unique uses in other fields, ranging from science to sp ...

In 1952, Leupold returned to studying ''S. pombe'' first at the

University of Zürich The University of Zurich (UZH, ) is a public university, public research university in Zurich, Switzerland. It is the largest university in Switzerland, with its 28,000 enrolled students. It was founded in 1833 from the existing colleges of the ...

from 1952 to 1963 and then as head of the Institute of General Microbiology at the

University of Bern The University of Bern (, , ) is a public university, public research university in the Switzerland, Swiss capital of Bern. It was founded in 1834. It is regulated and financed by the canton of Bern. It is a comprehensive university offering a br ...

from 1963 to 1986. During this time, his laboratory made major contributions to the understanding of genetic mutations and suppressors in ''S. pombe'', as well as the construction of a genetic map of this yeast. As the recognized leader in fission yeast genetics, Leupold had a great impact on the first generation of scientists to use ''S. pombe'' for genetic studies. In 1973,

Paul Nurse Sir Paul Maxime Nurse (born 25 January 1949) is an English geneticist, former President of the Royal Society and Chief Executive and Director of the Francis Crick Institute. He was awarded the 2001 Nobel Prize in Physiology or Medicine, along ...

spent a couple months with Leupold to learn ''S. pombe'' genetics before beginning his seminal studies on cell cycle control with

Murdoch Mitchison John Murdoch Mitchison (11 June 1922, Oxford – 17 March 2011, Edinburgh) was a British zoologist. Background Family Mitchison was the son of the Labour politician Dick Mitchison and his wife, the writer Naomi (née Haldane). The biolog ...

in Edinburgh, Scotland. Other notable ''S. pombe'' scientists who trained with Leupold include Peter Munz, Jürg Kohli, Herbert Gutz, Matthias Sipiczki and the late Pierre Thuriaux.

References

{{DEFAULTSORT:Leupold, Urs Academic staff of the University of Bern 20th-century Swiss biologists Academic staff of the University of Zurich 1923 births 2006 deaths