Barr body

noun \ ˈbär- \

Definition of Barr body

: a densely staining inactivated condensed X chromosome that is present in each somatic cell of most female mammals and is used as a test of genetic femaleness (as in a fetus) — called also sex chromatin

Origin and Etymology of barr body

Murray Llewellyn Barr †1995 Canadian anatomist

NEW! Time Traveler

First Known Use: 1961

in the meaning defined above

See Words from the same year

Medical Dictionary

Barr body

noun \ ˈbär- \

medical Definition of Barr body

: a densely staining inactivated condensed X chromosome that is present in each somatic cell of most female mammals and is used as a test of genetic femaleness (as in a fetus or an athlete) — called also sex chromatin

Biographical Note for barr body

Barr, Murray Llewellyn (1908–1995), Canadian anatomist. A professor of microanatomy, Barr specialized in cytological research, especially as it applies to genetically determined anomalies of sex determination and development, cancer, and mental illness. His most notable work dealt with sex chromatin, now known as the Barr body. In 1949 he noted that females had in the nuclei of their nerve cells a mass of chromatin that males did not. Further study revealed that this sex difference in the nuclei of resting cells is found in most mammals.