- Barr , Murray Llewellyn
- (1908–) Canadian geneticist and anatomistBarr was born in Belmont, Ontario, and was educated at the University of Western Ontario, gaining his BA in 1930, MD in 1933, and MSc in 1938. His association with Western Ontario was continued with his appointment as an instructor in 1936. He subsequently became professor of microscopical anatomy (1952), professor of anatomy and head of the anatomy department (1964), and emeritus professor (1979).Barr is best known for his discovery, made in 1949 in conjunction with Ewart Bertram, of the densely staining nuclear bodies present in the somatic cells of female humans and other female mammals. These are called sex chromatin or Barr bodies. Later studies by Barr and others revealed that the single Barr body in normal cells is one of the two X-chromosomes in a highly condensed and genetically inactive state. The other X-chromosome is in the diffuse state and is genetically active.Their discovery enabled Barr and his co-workers to devise a relatively simple diagnostic test for certain genetic abnormalities, in which cells rubbed from the lining of the mouth cavity (a buccal smear) were stained and examined microscopically. For instance, individuals suffering from Turner's syndrome, which usually affects females, have only one X-chromosome and lack Barr bodies. In contrast, males affected by Klinefelter's syndrome possess an extra X-chromosome and exhibit Barr bodies in their cells.Besides his work in cytogenetics and inherited human disorders, Barr is also noted for his descriptions of nervous-system anatomy. His publications include The Human Nervous System: an Anatomical Viewpoint (1972; 5th edn. (with J. A. Kiernan) 1988).
Scientists. Academic. 2011.
Look at other dictionaries:
Murray L. Barr — Murray Barr Pour les articles homonymes, voir Barr. Murray Llewellyn Barr est un biologiste américain, né le 20 juin 1908 à Belmont, Ontario et décédé le 4 mai 1995. Il a découvert en 1948 le corpuscule de Barr, amas de chromatine du noyau… … Wikipédia en Français
Barr body — A microscopic feature of female cells due to the presence of two X chromosomes in the female. One of these X chromosomes is inactive and is crumpled up to form the Barr body. * * * Barr body bär n a densely staining inactivated condensed X… … Medical dictionary
Murray Barr — Pour les articles homonymes, voir Barr. Murray Llewellyn Barr est un biologiste américain, né le 20 juin 1908 à Belmont, Ontario et décédé le 4 mai 1995. Il a découvert en 1948 le corpuscule de Barr, amas de chromatine du noyau spécifique des… … Wikipédia en Français
Murray Barr — Murray Llewellyn Barr, OC, FRSC, FRS (June 20, 1908 – May 4, 1995) was a Canadian physician and medical researcher who discovered with graduate student Ewart George Bertram, in 1948, an important cell structure, the Barr body . Born in… … Wikipedia
Barr-Körper — Der Zellkern eines menschlichen, weiblichen Fibroblasten wurde mit dem blau fluoreszierenden … Deutsch Wikipedia
Barr-Körperchen — Der Zellkern eines menschlichen, weiblichen Fibroblasten wurde mit dem blau fluoreszierenden … Deutsch Wikipedia
Barr body — noun Etymology: Murray Llewellyn Barr died 1995 Canadian anatomist Date: 1961 a densely staining inactivated condensed X chromosome that is present in each somatic cell of most female mammals and is used as a test of genetic femaleness (as in a… … New Collegiate Dictionary
barr body — ˈbär , ˈbȧ(r noun Usage: usually capitalized 1st B Etymology: after Murray Llewellyn Barr died 1995 Canadian anatomist : a densely staining inactivated condensed X chromosome that is present in each somatic cell of most female mammals and is… … Useful english dictionary
University of Western Ontario — This article is about the University located in Ontario. For the University located in Oshkosh, Wisconsin, known as “UW O”, see University of Wisconsin Oshkosh. The University of Western Ontario Motto Latin: Veritas et Utilitas Motto in English … Wikipedia
Университет Западной Онтарио — осенью Университет Западной Онтарио, англ. The University of Western Ontario, сокращённые наимено … Википедия