An experiment found that newborn rats who were genetically predisposed to be skittish, nervous, and high-strung would develop into calm, exploratory, and stress-resistant adult rats when raised by genetically unrelated, attentive mothers. The researchers concluded that:
A) although the rats' DNA did not change, the chemicals that controlled their gene expression did change.
B) the genes controlling the rats' behavior must have mutated.
C) although the rats' DNA changed, the chemicals that controlled their gene expression did not.
D) the epigenetic changes were inherited from the previous generation of temperamental rats and were only expressed when the environment was favorable.

Question

Quizplus · Accepted Answer

The experiment suggests that environmental factors can alter gene expression without changing the underlying DNA sequence, which is consistent with epigenetic modifications. The attentive mother rats likely provided a nurturing environment that triggered epigenetic changes in the offspring's gene expression, leading to a more calm and stress-resistant phenotype. The genetic mutations or inheritance of epigenetic changes from the previous generation are not supported by the results of the experiment.

An Experiment Found That Newborn Rats Who Were Genetically Predisposed