By the end of the first week of life, the promoter of a glucocorticoid receptor in the pups of neglectful rat mothers was more methylated than the same gene in pups of nurturing mothers. This means that
A) pups of neglectful and nurturing mothers had some differences in the structures of their chromosomes that occurred after birth.
B) the pups of the neglectful mothers displayed a lessened response to stressful stimuli.
C) the pups of the neglectful mothers possessed more glucocorticoid receptors than the pups of nurturing mothers.
D) all of the above occurred.

Question

Quizplus · Accepted Answer

The increased methylation of the glucocorticoid receptor promoter in pups of neglectful mothers suggests epigenetic changes (differences in gene expression regulation) that occurred after birth, not inherent structural differences in the chromosomes or an increase in glucocorticoid receptors.

By the End of the First Week of Life, the Promoter