Why is x chromosome inactivation necessary in human females?
1 Answer
Since human (and mammal) females have two X chromosomes, inactivation prevents them from having twice as many X chromosome gene products as males, who only possess a single copy of the X chromosome. This called dose compensation.
Which X will be inactivated is random. The inactivated X is seen as a Barr body in the nucleus.
One of the interesting things about the random expression of each X can be seen in female cats. Their hair color is found on the X chromosome. Since only one gene (black or red) will be expressed, you will see a random color pattern.
The pattern is on their skin and therefore in the hair.
This cat has dilute colors. Gray and cream.
