Epigenome

IDENTICAL TWINS: PINPOINTING ENVIRONMENTAL IMPACT ON THE
EPIGENOME

1. Often, the physical characteristics of genetically identical twins become increasingly
different as they age, even at the molecular level. Explain why this is so. (use the
terms "environment" and "epigenome")

When the twins are born they start out with the same epigenome, with only the imprinted genes from their parents. Once, the twins age and start to live different lives, they are exposed to different environments that shape their epigenomes.

2. Name 3-4 environmental factors that influence the epigenome.

Stress, diet, exposure to toxins, such as smoke and alcohol, and physical activities are a few examples of environmental factors that can have both positive and negative effects on the epigenome.


3. What is an imprinted gene?

Imprinted genes is the part of the epigenome that is inherited from one's parents. These genes are the only part of the epigenome that is passed down to new generations.

LICK YOUR RATS

1. Explain how a high-nurturing mother rat shapes her pup's epigenome, and what that
pup's response to stress will be.

A high nurturing mother will lick the pups and the pups will also grow up to be high-nurturing and relaxed just like their mother.

2. In rats, does licking by the mother activate, or deactivate her pup's GR gene?

Licking the pups activates the GR gene.

3. Explain how cortisol and the GR protein work together in the brain to relax a rat pup.
You may draw a diagram.

During fight or flight cortisol is released in the hippocampus. GR is also released to help calm the cortisol. So, the more GR there is, the faster the pup will be able to relax, the less GR, the longer it takes.

4. The rat nurturing example shows us how parental behavior can shape the behavior of
their offspring on a biochemical level. Relate this to humans and think about the personal
and social implications. Record your thoughts.

If a baby is raised in a high stress environment with little attention or care, the child will most likely grow up reflecting these behaviors. On the other side, if the same child was raised in a loving, caring, and calm environment the child is much more likely to grow up to be a calm, loving parent then the other child who grew up with stress.

NUTRITION & THE EPIGENOME

1. Explain how the food we eat affects gene expression.

Different foods have different chemicals which directly affect the expression of genes. Different amount of different or the same chemical can either turn a gene on or off.

2. Can the diets of parents affect their offspring's epigenome?

The diets of parents definitely affect their offspring. When a mother is pregnant the food she eats directly goes to the offspring, and at this stage of an offspring's life the nutrition they are receiving is vital.