What does the presence of a Barr body indicate?

What does the presence of a Barr body indicate?

The Barr body, also sometimes called the sex chromatin, is the inactive X chromosome in female somatic cells. In all of the female somatic cells, which don’t take part in sexual reproduction, one of the X chromosomes is active, and the other is inactivated in a process called lyonization, becoming the Barr body.

What is a Barr body in biology?

The Barr, or sex chromatin, body is an inactive X chromosome. It appears as a dense, dark-staining spot at the periphery of the nucleus of each somatic cell in the human female.

What is Barr body give the formula for the no of bar body in a cell?

Barr body is an inactive X chromosome present in a female cell. The number of Barr body is one less than the number of X-chromosomes. In the given example, there are total 4 X chromosomes. Hence, the number of Barr bodies are 4 – 1 = 3.

Why do females show a Barr body in their cells?

A Barr Body is an inactivated, condensed X chromosome found in female cells. To ensure that X-linked gene product doses are kept similar between males and females, one of the X chromosomes in a female becomes very condensed – the Barr body.

What happens to Barr bodies?

A Barr body (named after discoverer Murray Barr) or X-chromatin is an inactive X chromosome in a cell with more than one X chromosome, rendered inactive in a process called lyonization, in species with XY sex-determination (including humans). Barr bodies can be seen in neutrophils at the rim of the nucleus.

What is the significance of Barr body near female nucleus of neutrophils?

Recognition of a Barr body in a neutrophil is important in order to avoid reporting it as abnormal (unless two or more per neutrophil are seen). The Barr body is considered nonpathological unless associated with rare chromosome disorders.

Can a Barr body be reactivated?

Reactivation of a Barr body is also possible, and has been seen in breast cancer patients. One study showed that the frequency of Barr bodies in breast carcinoma were significantly lower than in healthy controls, indicating reactivation of these once inactivated X chromosomes.

Do Barr bodies replicate?

An inactivated X chromosome (Xi), which becomes transcriptionally silent as a result of the dosage compensation, forms the compact structure known as the Barr body on the nuclear periphery and replicates in the late S-phase, is an example of a bulk heterochromatin domain inside the nucleus in female mammalian somatic …