Dr. Murray Barr

Born: June 20, 1908
Birthplace: Belmont, Ontario
Died: May 4, 1995

Investigated the genetic basis of mental retardation

In 1948 Dr. Barr discovered a microscopic chromatin mass (Barr body) present in female but not male mammalian cells. Because of his discovery, researchers could investigate the genetic sex of individuals with ambiguous external genitalia, and conduct appropriate corrective surgery. Further investigations revealed a number of abnormal conditions in which two or more Barr bodies were found, many in association with mental retardation.

In 1962 Dr. Barr won a Joseph P. Kennedy Jr. Foundation Award for his contributions to the understanding of the causes of mental retardation. Dr. Barr taught histology and anatomy at the University of Western Ontario for many years, and published a popular text book in the field, The Human Nervous System: An Anatomical Viewpoint, which went through six editions during his lifetime. Dr. Barr became an Officer of the Order of Canada in 1968.

Fortune Favours the Prepared Mind

After serving in the Second World War, Dr. Barr was very interested in the effects of fatigue on the central nervous system. In 1949, with a $400 dollar research grant, a modest amount by today's standards, he used an electrical device to stimulate the nerve cells in cats. He and his graduate students were puzzled at a mass of chromatin in the nerve cells of some cats, and not in others. After an exhaustive examination that included varying the intensity of the stimulation, the length of the stimulation, and staining techniques, he concluded that this observation was attributed only to the sex of the animals. After thorough observations of other mammalian cells, including humans, the discovery was published. That mass of chromatin that was first observed was later named "sex chromatin", and is now referred to as the "Barr body". His discovery made it possible to determine the cellular sex of an individual and launched a new era of research into genetic disorders.