Definition of Barr body in English:

Barr body


  • A small, densely staining structure in the cell nuclei of females, consisting of a condensed, inactive X chromosome. It is regarded as diagnostic of genetic femaleness.

    • ‘We now know that the ‘darkly staining’ Barr body is the condensed, inactive X chromosome.’
    • ‘The formation of Barr bodies is the strategy that humans use for what is called dosage compensation.’
    • ‘If the child is genetically female then a Barr body should be evident in approximately 10-20 percent of the cells.’
    • ‘In some tissues, the inactive X chromosome can be identified in the nucleus as a Barr body and X inactivation provides an important model for the inheritance of gene expression.’
    • ‘If the Barr bodies of a normal female were missing, she would exhibit Turners Syndrome.’


1960s: named after the Canadian anatomist M. L. Barr (1908–95).


Barr body