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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Barr body is absent in female having –
assistant
The correct answer is  Barr body (Sex - chromatin)

It is a densely staining inactivated condensed 'X' chromosome that is present in each somatic cells of the female.
It is found in the nucleus.
It is used as a test of genetic femaleness → it is possible to determine the genetic sex of an individual according as to whether there is a chromatin mass present on the inner surface of the nuclear membrane of cells with resting or intermittent nuclei. Remember the following fact and the question will seem very easy.
Chromatid body (Barr body or sex chromatin) is derived from one of the two X-chromosomes which becomes inactivated.
The number of Barr bodies is thus one less than the number of X-chromosomes.

Note -

Barr body is found in female But -
Kleinefelter syndrome is male with Barr body.
Turner syndrome is female without Barr body.