Murray Llewellyn Barr Genetics

Discovered sex chromatin

The Story

Barr’s main interest was cytological research as it applies to sex anomalies and mental retardation. He is author of numerous publications in the field of cytology (the structure and function of cells), principally the cytology of the nervous system and human cytogenetics. His popular textbook on neuroanatomy, The Human Nervous System: An Anatomical Viewpoint is now in its 9th edition.

In 1949, Barr discovered sex chromatin, a substance made of DNA and protein, a discovery which made it possible to determine the cellular sex of an individual. Barr and his colleagues also devised the buccal smear test, whereby cells from the patient’s mouth are taken and examined for chromosomal defects. This test is now used extensively to screen patients, including newborn babies.

Sources: Canadian Medical Hall of Fame, Canadian Who’s Who 1993, Coalition For Biomedical & Health Research

The Person

June 20, 1908
Belmont, Ontario
Date of Death
May 4, 1995
Place of Death
London, ON
Professor Emeritus of Anatomy, UWO
  • BA, U Western Ontario, London, Ontario, 1930
  • MD, 1933
  • MSc, 1938
  • Flavelle Medal (Royal Society of Canada),1959
  • Ortho Medal (American Society for the Study of Sterility)
  • Award of Merit (Gairdner Foundation)
  • Maurice Goldblatt Award (International Academy of Cytology)
Last Updated
July 28, 2011
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