Barr bodies and the inactivated X-chromosome?

Question

Barr bodies only occur in female nuclei, and inactivated X chromosomes stay inactive in their descendants.

How does this work for a male descendant? Wouldn't his XY chromosomes contain the inactivated X chromosome then? I'm not getting this. Thank you!!

Answer 1

The inactivated X chromosome is ' dosage compensation'.

Answer 2

This refers to the somatic cell line and daughter cells.  The second X inactivates randomly during development.  There can be a patchy distribution of the two inactivated chromosomes in the body.

If it referred to germ line, males could not be born.

Answer 3

Which X chromosome is inactivated in each cell is random - so some cells have the paternally-derived X chromosome inactivated, and some have the maternal one.

Another thing to remember, however, is that the inactivation is *reversible* - not permanent. So in germ-line cells, the X is "re-activated" when gametes are made.

In males, the X chromosome is never inactivated. They need the genes on the chromosome to survive.