Epigenetics Questions

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.
Their environmental factors are completely responsible for the change in their epigenome. Twins who spend time apart will become very different as they age, and twins who spend time together will become different- but much less different than those who spend time apart.

2. Name 3-4 environmental factors that influence the epigenome.
Nutrition, stress, social interaction, and physical activity.

3. What is an imprinted gene?
An imprinted gene is a gene that may or may not me expressed, depending on which parent passed on said gene to their offspring.


YOUR ENVIRONMENT, YOUR EPIGENOME

1. Discuss factors in your daily life that could be affecting your epigenome.
I feel like I have an adequate diet and a good amount of exercise each day, but stress and lack of sleep are certainly affecting my epigenome. Stress is thought to change a certain area of the genome, which will alter the expression of a hormone that controls mood. Basically, the more stressed I feel, the angrier or unhappier I will become.


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.
The more a mother nurtures its pup, the easier it will be for the pup to relax after stress.

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

3. Explain how cortisol and the GR protein work together in the brain to relax a rat pup.
Cortisol, a hormone, is released in the brain during a fight or flight response. This hormone binds to the GR protein, calming the rat pup down. The more GR a rat has, the less time it remains stressed for.

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.
Children with caring and nurturing mothers will grow up to be happier and smarter people who succeed in life. Children with uncaring parents or parents who have issues (with each other) may grow up to be uncaring people themselves, and will probably have a harder time dealing with stress. On a biochemical level, the cortisol hormone and GR protein function the same way as rats' do.


NUTRITION & THE EPIGENOME

1. Explain how the food we eat affects gene expression.
The nutrients we get from food affect our metabolism. Once they enter our metabolic pathways, they're turned into useful molecules. One of these pathways makes methyl- which produces healthy offspring when a mother is pregnant. (It has another function, which will be described later.)

2. Can the diets of parents affect their offspring's epigenome?
Yes, the agouti gene in a human (or a rat) is affected by the mother's diet. A methylated agouti gene results in a healthy offspring, while an unmethylated agouti gene results in the opposite.


EPIGENETICS & THE HUMAN BRAIN

1. How does dietary methyl influence gene expression?
It turns on and off certain genes. Diets rich with nutrients full of methyl will positively alter an organism's epigenome in its early stages of development.

2. Why do Toxins affect gene methylation?
Take BPA as an example. It was made to create polycarbonate plastic, and was horribly unsuitable for consumption. Mothers who consumed it gave birth to obese and unhealthy offspring. The reason for this was because it decreased the methylation of the agouti gene.

DNA Fingerprinting Lab

1. DNA is unique for everyone. The only exception is if a person has what?
An identical twin

2. What are DNA fingerprints used for?
Determining biological parents, or determining the suspect of a crime.

3. What “crime” was committed?
Someone licked a NOVA holographic lollipop.

4. What bodily fluid was removed from the “crime scene” to get DNA?
Saliva.

5. What does a restriction enzyme do?
They cut the long DNA molecules in certain places.

6. What is agarose gel?
It's a molecular strainer, allowing small pieces of DNA to move through.

7. What is electrophoresis?
A process that moves moleecules with an electric current.

8. Smaller fragments of DNA move ____________ than longer strands?
Easier

9. Why do you need to place a nylon membrane over the gel?
So the DNA can be separated from the gel.

10. Probes attach themselves to __________
DNA fragments.

11. Which chemical in your “virtual lab” is radioactive?
Probes.

12. Sketch your DNA fingerprint.

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13. Based on your DNA fingerprint, who licked the lollipop?
Honey Sweet

14. What kinds of things could you do at the DNA workshop?
Make new DNA strands, replicate DNA, or perform protien synthesis.

15. Whodunnit? Officials have sticky problem in Haiti Maggie Fox. November 18, 2010
The cholera outbreak in Haiti is currently being tracked. Suspects include Nepalese troopers from a recent UN mission.

Mitosis Simulation Questions

1. Which stage does the following occur
Chromatin condenses into chromosomes: prophase
Chromosomes align in center of cell: metaphase
Longest part of the cell cycle: interphase
Nuclear envelope breaks down: prometaphase
Cell is cleaved into two new daughter cells: cytokinesis
Daughter chromosomes arrive at the poles: telophase

2. More chromosome questions
How many chromosomes are visible at the beginning of mitosis? 23
How many are in eachdaughter cell at the end of mitosis? 46
The little green T shaped things on the cell are: centrioles
What happens to the centrioles during mitosis? spindle fibers grow on them.

3. Sketches
Prophase:
Metaphase:
Telophase:


4. Amount and percent of collected cells
Interphase: 20 (55%)
Prophase: 10 (28%)
Metaphase: 3 (8%)
Anaphase: 2 (6%)
Telophase: 1 (3%)
Total: 36 (100%)

5. Whitefish and onion views

Whitefish:
View 1: cytokinesis
View 2: metaphase
View 3: prophase
View 4: telophase

Onion:

View 1: metaphase
View 2: prophase
View 3: interphase
View 4: cytokinesis
View 5: cytokinesis