June 20, 1908

(Belmont, Ontario)


May 4, 1995


MD, University of Western Ontario (1933)
MSc, University of Toronto (1938)

Awards & Honours:

1972: Fellow of the Royal Society of London

1968: Officer of the Order of Canada

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Picture of Murray Barr, MD

Discovered an important cell structure now known as the Barr body

Portrait of Murray Barr

A builder of the field of human cytogenetics

Sometimes, a big discovery comes from a microscopic level. When Drs. Murray Barr and E.G. Bertram published an article in Nature regarding their findings of a sex chromatin body, they inspired a whole new era in research and diagnosis of genetic disorders. This discovery of a dark staining spot in the nucleus of female cells, later referred to as the Barr body, revealed the presence of an inactivated and condensed X chromosome, making it possible for the first time to count X chromosomes in a cell and relate that to abnormal chromosomal states. This was the forerunner of the discipline of genetics, and specifically the field of human cytogenetics focussing on the role of chromosome abnormalities in childhood disease.  

Key Facts

Was the first to establish a link between sex chromosome abnormalities and human disease

Was the first to record dark staining bodies (Barr bodies) in the nucleus of female cells and show that they were a manifestation of condensed X chromosomes (sex chromatin) in cells with more than one X chromosome

His textbook, The Human Nervous System, became a worldwide standard for neuroanatomy, and was translated into numerous different languages

Influenced a generation of medical students as a devoted and captivating neuroanatomy professor

Nurtured an interest in the history of medicine and published A Century of Medicine at Western

Awarded seven honorary degrees

Professional timeline

Impact on lives today

Dr. Barr’s investigations recording the number of inactivated X chromosomes (Barr bodies) in normal cells and in cells from children with congenital anomalies led to the discovery of two X chromosomes in males with Klinefelter syndrome and a single X in females with Turner syndrome.  Normal males have one X chromosome and females have two X chromosomes, one of which is inactivated.  His further development of the buccal smear test, utilizing cells scraped from the inside of the cheek, provided a rapid non-invasive method to screen large numbers of individuals for sex chromosome alterations.  This seminal work provided proof of principle for the new field of cytogenetics for diagnosis of chromosome abnormalities in children.   

Picture of Murray Barr, MD


  • Murray Barr posthumously inducted into the Canadian Medical Hall of Fame

    Hull, Québec

  • Authored by Dr. Murray Barr, the first edition of "The Human Nervous System" was published

    Health and Medical Education & Training

    By 1983, the textbook was already in its 4th edition.

  • With Dr. K.L. Moore, Dr. Barr developed the buccal smear test, a non-invasive method of gathering human cells from the lining of the mouth for genetic testing

    Cells, Genetics & Genomics

    In combination with karyotyping, it allowed scientists to identify individuals with an abnormal number of sex chromosome bodies, furthering diagnosis and treatment of congenital disorders.

  • Image of Barr bodies under microscope

    Drs. Barr and Bertram made a ground-breaking discovery later referred to as the Barr body

    Cells, Genetics & Genomics

    They identified a dense mass of chromatin (material containing the genetic code) present only in female nerve cells, and demonstrated its origin as a condensed X chromosome in females with two X chromosomes.

  • Soon after the war, Barr returned to Western University

    He remained at Western until his retirement in 1977.

  • Canada went to war, and so did Barr

    He served as a distinguished Wing Commander with the Royal Canadian Air Force.

  • Experiencing the challenges of running of medical practice during the Depression, Barr pursued a master’s degree in science

    At the University of Toronto, his research focused on the synaptic end-builds of motor neurons.

  • Barr graduated from medical school at the University of Western Ontario

    He then sought further training with a general internship at Hamot Hospital in Erie, Pennsylvania.


The legacy of the Barr body and his devotion to teaching live on.