Epigenetics & The Environment

Identical Twins
-When twins are younger they have the same environment so the receive the same epigenome 
tags but when the grow older and do not share the same environment they receive different tags changing their appearance and molecular level.
-Environmental factors include: Physical activity, diet, exposure to toxins and stress
-Epigenetic tags are erased from mom and dads chromosomes during the first day of fertilization but some tags remain which are imprinted genes
Rats
-A high nurturing mother will raise a high nurturing pup. Does not matter who gave birth to it, just who raised it. It will become a relaxed rat. It may let down its guard too quickly and is more likely to be eaten by predators.
-Mothers activate the pups GR gene by licking them.
-Cortisol binds to the GR gene and the hippocampus sends out a signal to turn off the stress circuit and turns off the fight or flight response and cortisol production.
-When a child has low nurturing people in their childhood they are more likely to become a low nurturing person themselves. When a child has a high nurturing majority of people in their life than they will more likely become high nurturing. External factors can change the high/low nurturing in a person.
-Nutrition & The Epigenome
-The nutrients we get from from our food enter metabolic pathways where they are manipulated modified and molded into molecules that body can uses. It is responsible for making the methyl groups which are important epigenetic tags that silence genes 
- The mothers diet can cause critical changes that stick with you for the rest of your life. Lack of methyl-donating folate or choline during late fetal or early development causes certain areas of the genome to be under-methylated for life
Epigenetics &  The Human Brain
-Methyl influences gene expression by stabilizing it. High levels of methyl means less rRNA production which means fewer ribosomes which result in less protein production. 
-Toxins have a long term affect on the body.Some drugs work by changing gene expression. These changes stabilize through epigenetic mechanisms like DNA methylation, reversing the effects of the disease.