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November 14, 1966

The Sex Chromatin

JAMA. 1966;198(7):795. doi:10.1001/jama.1966.03110200151068

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In 1947 Dr. Murray L. Barr interested a graduate student, Ewart G. Bertram, in an investigation of possible structural changes in the nerve cells following intense stimulation. In the course of their studies Barr and Bertram, working on cats, noted that the hypoglossal neurons of some animals had a nucleolar satellite which was absent in others. At first this finding was a real puzzle and a technical failure in the staining of the preparations was suspected. When other possible variables were considered, it became apparent that all animals whose nucleoli contained satellites were females but those who lacked them were males. This discovery of sex chromatin, made less than 20 years ago without facilities more complex than the staining jar and the microscope should serve as inspiration to investigators who sometimes feel that all of the simple, straightforward discoveries have been made.

The finding of the sex chromatin body has