Epigenetics

Lab 2: Epigenetics

Name: Jonathan Visentin   Lab Date: 09/08/2016

Goal:  Today’s activity will help you gain a better understanding of the interplay of your genetics and environmental factors that can affect the expression of your genetics.

For many years, scientists believed that our physiology was solely a function of what genes we had inherited from our parents. But in recent years, scientists are learning about our epigenome;

explore this website → http://learn.genetics.utah.edu/content/epigenetics/ to learn about epigenetics and how you are more than just the sum of your genes!

First watch the introductory video entitled “Epigenome at a Glance” and answer the following:

1. What is the epigenome?

The epigenome is a multitude of chemical compounds that can tell the genome what to do.

1. What is the function of the epigenome?

A human being has trillions of cells, specialized for different functions in muscles, bones and the brain, and each of these cells carries essentially the same genome in its nucleus. The differences among cells are determined by how and when different sets of genes are turned on or off in various kinds of cells. Specialized cells in the eye turn on genes that make proteins that can detect light, while specialized cells in red blood cells make proteins that carry oxygen from the air to the rest of the body. The epigenome controls many of these changes to the genome.

1. What sorts of environmental influences can cause the epigenome to change?

Environmental conditions can affect DNA indirectly by modifying epigenetic factors. Some epigenetic factors come from natural sources (such as the food we eat), or are even encoded in the DNA, and are a normal part of gene regulation. That is, the epigenome helps control which genes are active in a particular cell, and therefore, which proteins are transcribed locally.

Next, watch the video entitled “Insights from Identical Twins” and answer the following:

1. Why do identical twins become more different as they age?

Because identical twins develop from a single fertilized egg, they have the same genome. So any differences between twins are due to their environments, not genetics.

1. How do identical twins’ genetic code compare to each other at birth and at age 60?

1. How do identical twins’ epigenomes compare to each other at birth and at age 60? Explain your answer.

Chromosome 3 pairs in each set of twins are digitally superimposed. One twin's epigenetic tags are dyed red and the other twin's tags are dyed green. When red and green overlap, that region shows up as yellow. The 50-year old twins have more epigenetic tags in different places than do 3-year-old twins.

Now click on “Lick Your Rats” and read the text at the top of the page regarding rats grooming their pups. Now click on the “Go” button under the box with the rat. After listening to the audio about the GR gene, click on the “Start” button under the rat. Try being a good mother rat (lots of grooming) and a more neglectful mother (little grooming).

1. What is the GR gene?

The Glucocorticoid Receptor (GR) Helps Shut Down the Stress Response

1. How effect does more or less grooming have on a rat pup?

Less: Pup’s GR gene will impact on its adult personality. (inactive, hard time relaxing after stress)

More:Pup will have an easy time relaxing after stress

1. Can epigenetic patterns be reversed?  Explain and give an example.

The term has evolved to include any process that alters gene activity without changing the DNA sequence, and leads to modifications that can be transmitted to daughter cells (although experiments show that some epigenetic changes can be reversed).

 The researchers found four times as many differentially expressed genes between a pair of 50-year-old twins compared to 3-year-old twins, and the 50-year-old twin with more DNA hypomethylation and histone hyperacetylation (the epigenetic changes usually associated with transcriptional activity) had the higher number of overexpressed genes. The degree of epigenetic change therefore was directly linked with the degree of change in genetic function.(Web, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1392256/)