8 Dosage compensation in human females results in the geneti

8. Dosage compensation in human females results in the genetic silencing of one of the X chromosomes -- but XO females (who have one active X chromosome) show distinct phenotypes (Turner syndrome) not shown by XX females. A. Suggest two explanations for this difference. (2 points) B. How many Barr bodies would be found in a XO female? (1 point)

Solution

A)XO females show distinct phenotypes because because the XO females having Turner syndrome usually exhibit numerous deleterious phenotypes.Moreover there is apr resence of escaper genes which is usually present within the Xist domain .These genes suggest that X inactivation usually acts on the various kinds of. individual genes

Another reason is that the process enrichment of heterochromatin marks which happens on the inactivated X chromosome results in many genes being silenced on the X.

B)There are no Barr bovies in XO female as there Barr bodies require multiple X\'s.