Question

What is the inactivation of the X chromosome? What is a Barr body?

Answer 1

A normal human female is expected to have a mosaic phenotype due to the inactivation of one X-chromosome and one Barr body (contains inactive X chromosomes in the somatic cells). Each female carries one bare body in their somatic X-chromosomes means one X-chromosome is active and another is inactive while males contain no Barr body because they carry only one X-chromosome.

The Barr bodies are selected randomly, means the inactivation process is random, during which the dominant gene generally overcome the recessive gene (so, most of them display the dominant allele). And another thing is, these inactivates X-chromosomes are not completely inactive.