If each interphase nucleus in a preparation of normal rat epithelial cells is found to contain a single Barr body, one can conclude that
A) the cells are in meiotic prophase.
B) all of the chromatin in these cells is inactive.
C) the DNA in these cells has replicated.
D) the cells are not transcribing any genes.
E) the cells came from a female rat.

Question

Quizplus · Accepted Answer

A Barr body is an inactive X chromosome in the nuclei of female mammals. Therefore, the presence of a Barr body in each interphase nucleus indicates that the cells came from a female rat.

If Each Interphase Nucleus in a Preparation of Normal Rat