During an era of considerable population shifting, Murray Barr managed to live and to make a career within a few miles of his birthplace. Except for active service with the RCAF during World War II and for postgraduate study or attendance at medical conferences, Barr spent his entire life in London, Ontario, and environs. Nevertheless, he had an outstanding career in cytogenetics and neuroanatomy.

Barr’s international fame derived from one fundamental discovery, made in late 1948. While he and a graduate student, Mike Bertram, were carrying out experiments on cells from the nervous systems of mammals, they noticed that some of the cells, when microscopically examined, revealed small dark masses not present in cells from other animals. Probably the masses had been noticed but ignored by earlier investigators. Barr wanted to know what they were. After painstakingly reviewing many possibilities, he checked the lab records and realized that these strange bodies were always present in female animals, but never in males.
 

Dr. Murray Barr gained international prominence through his discovery in 1948 of the “sex chromatin.” His work, considered the most important contribution to Canadian medical science since the discovery of insulin in 1921, led to his nomination for the Nobel Prize in Physiology and Medicine. He was recognized in 1962 for this achievement when he became one of the first recipients of the Joseph P. Kennedy Jr. Foundation Award. Dr. Murray Barr, as viewed here, received this prestigious award from President John F. Kennedy. [Photo, courtesy Dr. R.M.Barr]

The mass, called a nuclear chromatin mass, or Barr body, provided a stimulus to international research. The science of cytogenetics, that branch of biology concerned with the structure, function, and life history of cells, arose because of the discovery. The ramifications profoundly changed the way the world looks at and understands the genetics of sexual structure.

First, though, Barr had to prove that the phenomenon was not an isolated situation affecting only a few individuals or only one species. So he and various graduate students examined the cells of monkeys, cats, dogs, skunks, goats, rats, rabbits, and many other species including, of course, humans. The nuclear body was present in all females and in no males. At first, biopsies of tissue were used; later it was found that the cells obtained by gently scraping the mucosa inside the mouth would also give appropriate findings.

Clinical use of the test followed quickly. Tissues from so-called hermaphrodites and pseudo-hermaphrodites were examined and gave predictable but not clinically useful results. The test was then used to study patients with the disorders known as Turner’s Syndrome (women with congenital ovarian disorder) and Klinefelter’s Syndrome (men with congenital testicular disorder). The test showed that the latter had an extra X chromosome; they could thus be diagnosed within a larger population. Ultimately, another investigator demonstrated that the nuclear mass itself was an entire X chromosome.

An important outcome of this research, the technicalities of which are complex, was to prove clinically useful with respect to women who have spontaneous abortions. Physicians traditionally have attempted to devise methods to permit women subject to this unfortunate tendency to retain their pregnancies. But researchers in Barr’s lab found that a substantial proportion of the aborted fetuses had serious chromosomal abnormalities. This finding forced obstetricians to rethink the appropriateness of their well-intentioned attempts to prevent early spontaneous abortion.

Where these and ensuing research projects will lead us is conjectural. But at a time when genetic manipulation, cloning, and other related activities are being pursued in laboratories around the world, it seems evident that the field essentially created by Murray Barr will play a major role. Cytogenetics has, of course, become a highly controversial area with major ethical and religious impact.

Barr’s interests were not limited to cytogenetics. He was a gifted teacher of neuroanatomy. He also wrote a book on medical history that has helped fill a gap in our knowledge of that field. Not surprisingly, given his personal proclivity to stay in southwestern Ontario, Barr’s publication emphasizes the history of the medical school at the University of Western Ontario, his alma mater.

Of the many honours Barr received in recognition of his work, he especially prized the Joseph P. Kennedy Jr. Foundation Award for 1962, presented to him by President John F. Kennedy. This recognized his contributions to understanding how mental retardation arises genetically. This Canadian medical achiever was also made an Officer of the Order of Canada (1968) and received numerous other awards and honorary degrees.

He died in 1995, just a few months after his wife of half a century passed away. He and Mrs. Barr had four children, two of them physicians and one a nurse, and all resident in or near London.

Charles Roland