Скачать или смотреть Congenital Anomalies of the Barr Body; Turner's syndrome and Klinefelter's syndrome

Females have two X chromosomes. Since the somatic cells of females are not involved in sexual reproduction. Here one of the two X chromosomes is inactivated by lyonization. This inactive X chromosome is known as a Barr body.

The process of X-inactivation was discovered by Mary F. Lyon, a British geneticist. One X-chromosome is inactivated so that unnecessary information is not passed on to the next generation. The amount of expression of X-chromosome genes should be equal in both males and females.

The active X-chromosome is enclosed within euchromatin, whereas, the inactive X-chromosome is enclosed within heterochromatin. The inactive X-chromosome is compacted and is not accessible to the molecules involved in transcription.

In X-inactivation, the X chromosome is compacted to create a small, dense structure called the Barr body.

#barrbody