Mark Bretscher (born Cambridge, England, January 8, 1940) is a British biological scientist and Fellow of the Royal Society. He works at the Medical Research Council Laboratory of Molecular Biology in Cambridge, United Kingdom. He is currently studying how animal cells migrate.
Mark Bretscher was educated at Abingdon School in 1951, followed by Gonville and Caius College, University of Cambridge in 1958. He was visiting professor in biochemistry and molecular biology at Harvard University (1974–75) and Eleanor Roosevelt Cancer Society Fellow and visiting professor, Stanford University (1984–85). He was head of the cell biology division, MRC Laboratory of Molecular Biology at the University of Cambridge and was elected a Fellow of the Royal Society in 1985.
Bretscher's main contributions lie in the areas of the mechanism of protein biosynthesis, in the structure of cell membranes (especially that of the human red blood cell) and in how animal cells move. He is the principal protagonist of the membrane flow scheme for cell locomotion, which is largely based on how cap formation occurs. Using the amoeba Dictyostelium discoideum as an animal for study, he has identified the first two genes whose protein products are required for this creature to migrate.
His father was Egon Bretscher, the nuclear physicist. He is married to Barbara Pearse, another cell biologist. He lists his hobbies as "walking, creating wild environments, early English portraits and furniture."
- Mark S. Bretscher page at Laboratory of Molecular Biology
- Mark S. Bretscher. Curriculum Vitae
- Obituary of Francis Crick, The Independent
-  Obituary of Francis Crick by Mark Bretscher and Peter Lawrence, "Current Biology".
Books containing references to Mark Bretscher
- John Finch; 'A Nobel Fellow On Every Floor', Medical Research Council 2008, 381 pp, ISBN 978-1-84046-940-0; this book is all about the MRC Laboratory of Molecular Biology, Cambridge.
- Robert Olby; 'Francis Crick: Hunter of Life's secrets', Cold Spring Harbor Laboratory Press 2009, 537pp, ISBN 978-0-87969-798-3.
- Matt Ridley; 'Francis Crick: Discoverer of the Genetic Code', Harper Collins 2006, 224pp, ISBN 978-0-06-082333-7.