Question

A Barr body is a differentially staining chromosome seen at the periphery in some interphase nuclei of mammals with two or more X chromosomes. How many Barr bodies will be there in relation to the number of X chromosomes? What is the nature of the Barr body?

1) There will be one less Barr body than the number of X chromosomes, and the Barr body is considered genetically inactive.
2) There will be one more Barr body than the number of X chromosomes, and the Barr body is considered genetically active.
3) There will be the same number of Barr bodies as the number of X chromosomes, and the Barr body is considered genetically active.
4) There will be the same number of Barr bodies as the number of X chromosomes, and the Barr body is considered genetically inactive.

Answer 1

The number of 1) Barr bodies is one less than the number of X chromosomes, and the Barr body is genetically inactive.

Step-by-step explanation:

The number of Barr bodies in relation to the number of X chromosomes in mammals is one less than the number of X chromosomes. So, if a mammal has two X chromosomes, it will have one Barr body. The nature of the Barr body is that it is considered genetically inactive, meaning that the genes on the Barr body are not expressed.