Epigenetics is the study of changes in gene expression that do not involve changes to the underlying DNA sequence. It involves mechanisms like DNA methylation and histone modification that turn genes on and off. Epigenetic markers can be inherited from parents and influence traits and disease risk. While the genome contains the basic instructions, the epigenome controls which genes are expressed and when. Epigenetic changes may be influenced by environmental factors and can affect health by triggering conditions like cancer.
2. What is Epigenetics?
The study of changes in the way a
gene is carried out without any
actual changes to the DNA
occurring
Literally Epigenetics means “above
genetics”
3. So what’s the background?
Epigenetics doesn’t have very much
history to it since it is such a new
field to study!
Conrad Waddington first coined the
term Epigentics in the 1940’s .
In 1975 two groups announced that
DNA methylation could affect gene
expression.
4. What does it do?
Think of it this way, if the genome
The
was a computer, the hardware of epigenome
the computer, then the epigenome never
actually
would be the soft ware of the does the
work. The
computer. It tells the computer genome
when to work, how to work and how does the
work that the
much of that work to do. epigenome
tells it to do.
5. How it works.
Methyl groups
(made of one carbon and three hydrogen atoms),
latch onto DNA near a gene and tells it whether to
express the trait or not
Histones also play a part
Histones are a type of protein that genes coil
around
Tightly wound= gene is expressed less
Loosely wound= gene is expressed more
6. Techniques/Methods
Methylation
Most common of the techniques
Adds a methyl group
Phosphorylation
Regulates genes
Acetylation
Induced transcription
7. The difference is?
Genome Epigenome
Your actual gene Attaches itself to
your gene
Does the work Tells your gene what
assigned to it to do (like how to
express a trait)
8. Inheritance
So if you do Sometimes yes and sometimes
something
during your no…
life that Someepigenetic tags stay in place
gives you a
specific when someone has offspring
epigenome This is epigenetic inheritance
will it be
passed Others are completely wiped away so
down?
the child can start from scratch
->
9. Example of this is:
An experiment was done with genetically identical mice. Most were
fat but some were skinny. Both these mice have a one gene called
agouti but in the yellow mouse it stays on all of the time, and this
causes obesity.
So why is the thin mouse thin, if they are genetically identical?
Well, in the brown (thin) mouse there is a tiny chemical “tag” that has
attached itself to the agouti gene shutting it down.
In order to get thin brown mice instead of fat yellow mice, you can feed
the pregnant mothers a diet rich in methyl groups to form tags and
ultimately turn the gene off. This dramatically shifted the coat color from
yellow to brown and produced many more brown mice.
This is important because the coat color is a tracer, or an indicator that
the gene is in fact turned off. This shift of the phenotype is called an
epigenetic fix, and it was also inherited by the next generation of mice,
regardless of what their mothers ate.
10. Future Implications
When the chemical tags in control of our genes
change it opens the door for cells to become
abnormal, which can trigger diseases like cancer.
So technically, a few misplaced tags can kill you,
but this could be a good thing. Traditionally cancer
has been thought to only come from broken
genes. It is a lot harder to fix broken genes than to
reposition some epigenetic tags. Amazingly
enough, there are already some drugs that will
work in rearranging the tags. The results are
incredible, there are no horrible side effects and in
one trial half the patients went into remission.
