Monday, December 6, 2010


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") The environment at birth and until around the time when they begin school is the same. Over time, the epigenome changes from the other twin due to the difference in environment, stress, diet, and many other factors.
2. Name 3-4 environmental factors that influence the epigenome. Diet, stress, physical activity, and environment.
3. What is an imprinted gene? An imprinted gene is when the epigenomic tags from your parents stay on your chromosomes.


1. Discuss factors in your daily life (ie. Diet, exercise, stress etc.) that could be affecting your epigenome. Diet, stress, amount of physical activity, environment, etc.


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 rat shapes her pup's epigenome by stimulating the epigenome. That pup's response to stress will be very calm after stress.
2. In rats, does licking by the mother activate, or deactivate her pup's GR gene? 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. Lots of cortisol makes it easier for the rat to calm down from stress. If the pup was nurtured a lot have more GR protein in the hippocampus. Cortisol attaches to the GR protein, creating the easiness of calming down quickly, because stress is "headquartered" in the hippocampus.
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 your parents abuse you while you are young, you will most likely have a hard time calming down from alarming or stressful situations. On the other hand, if you were brought up by loving, nurturing parents, it will be easier for you to calm down from alarming or stressful situations.

1. Explain how the food we eat affects gene expression. Diets high in these methyl-donating nutrients can rapidly alter gene expression, especially during early development when the epigenome is first being established.
2. Can the diets of parents affect their offspring's epigenome? Yes, if a grandparent or parent went an extended period without proper nutrients, it will effect the offspring or the grandchild. It will either effect them physically, or internally, such as reproductive system issues, mental issues, or any other issues.


1. How does Dietary methyl influence gene expression? More methyl means less rRNA production, which means fewer ribosomes, which means less protein production. Less protein production accounts for weak muscles, bones, and can cause many diseases.
2. Why do Toxins affect gene methylation? Drugs of abuse such as cocaine trigger epigenetic changes in certain brain regions, affecting hundreds of genes at a time. Some of these changes remain long after the drug has been cleared from the system. Research in this area suggests that some of the long-term effects of drug abuse and addiction (including high rates of relapse) may be written in epigenetic code.

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