Mary F. Lyon

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This article is about the 20th century British geneticist. For the 19th century American educator, see Mary Lyon.
Mary F. Lyon
Mary Frances Lyon.png
Born (1925-05-15) 15 May 1925 (age 89)
Norwich, England
Alma mater Girton College
Doctoral advisor R A Fisher
Known for discovery of X-chromosome inactivation
Notable awards Royal Medal (1984)
William Allan Award (1986)
Wolf Prize in Medicine (1997)

Mary Frances Lyon, FRS (born 15 May 1925) is an English geneticist, who is best known for her discovery of X-chromosome inactivation, an important cytogenetic phenomenon.

Childhood and education[edit]

Mary Lyon was born on 15 May 1925 in Norwich, England as the daughter of a civil servant and a schoolteacher. She was educated at a grammar school in Birmingham. During the second world war, she pursued her studies at Girton College at the University of Cambridge,[1] where she read zoology, physiology, organic chemistry and biochemistry, with zoology as her main subject. During that time she became interested in embryology. She went on to do her PhD with R A Fisher, who was Professor of Genetics in Cambridge, where she characterized a mutant mice strain. During the course of her PhD she moved to Edinburgh.


After her PhD Mary Lyon joined the group of Conrad Hal Waddington, funded by the Medical Research Council to investigate mutagenesis and the genetic risks of radiation. In 1955, her group moved to the MRC radiobiology unit in Harwell. She has published many papers on radiation and chemical mutagenesis and on studies of mutant genes. She was head of the Genetics Section of the MRC Radiology Unit at Harwell from 1962 to 1987. She retired from active research in 1990.

X-inactivation also known as Lyonization[edit]

It was while working on radiation hazards in 1961 that she discovered X-chromosome inactivation, for which she is best known.[1] Her research elucidated the genetic control mechanisms of the X chromosome, which explains the absence of symptoms in numerous healthy women that are carriers of diseases associated with the chromosome. An example of X chromosome deactivation is Duchenne muscular dystrophy. Dr. Lyon has also done extensive work on the mouse t-complex,[2] and made many other contributions to mammalian genetics.


Mary Frances Lyon is a Fellow of the Royal Society, a Foreign Associate of the U.S. National Academy of Sciences, and a Foreign Honorary Member of the American Academy of Arts and Sciences. In 1994 she won the Mauro Baschirotto Award in Human Genetics, in 1997 the Wolf Prize for Medicine, for her hypothesis concerning the random inactivation of X-chromosomes in mammals. In 1997 she also received the Amory Prize, for genetic discoveries relating to mammalian sex chromosomes. In 2004 she was awarded the March of Dimes Prize in Developmental Biology. In 2006 she received the Pearl Meister Greengard Prize awarded by the Rockefeller University.

Awards and recognition[edit]


Gene Action in the X-chromosome of the Mouse (Mus musculus L.) Nature 190, 372 - 373 (22 April 1961).


  1. ^ a b Peter Harper (11 October 2004). "Mary Lyon". Genetics and Medicine Historical Network, Cardiff University. 
  2. ^ Mary F. Lyon (1986). "Male sterility of the mouse t-complex is due to homozygosity of the distorter genes". Cell (Cell Press) 44 (2): 357–363. doi:10.1016/0092-8674(86)90770-1. 


  • Oakes, Elizabeth H. Lyon, Mary Frances. International Encyclopedia of Women Scientists. New York, NY. Facts On File, Inc. 2002. Facts On File, Inc. Science Online. [1].
  • A short biography of Mary Lyon.

External links[edit]