Question

In a series of studies by Meaney and colleagues, rat pups were randomly assigned to be raised by surrogate mothers who spent a lot of time licking and grooming (high LG) them or surrogate mothers who spent little time engaging in this behavior (low LG). Rat pups raised by low LG surrogate grow up to be _____ fearful in novel situations, which can be attributed to a(n) _____ in DNA methylation.

A)less;increase
B)less;decrease
C)more;increase
D)more;decrease

Answer 1

B)less;decrease

Step-by-step explanation:

The series of experiments performed by Meaney and colleagues, established a relationship between stress, maternal care and the gene expression .

In the experiment the pups were separated from their mothers into two groups:

1. High licking and grooming mothers

2. Low licking and grooming mothers.

It was found out that the pups belonging to high LG mothers had a greater density of glucocorticoid receptors in their hippocampi compared to those of low LG mothers.

Due to this differential expression low LG surrogate raised pups were less fearful in novel situations and this was attributed to epigentic reporgraaming that is a decrease in DNA methylation.

Answer 2

Less, Decrease

Step-by-step explanation:

Rat pups raised by low LG surrogate grow up to be less fearful in novel situations, which can be attributed to a(n) decrease in DNA methylation.

DNA Methylation is a process by which methyl groups are added to the DNA molecule. It can change the activity of DNA segment without changing the sequence.