Connor Nielson
ANTH 1020
Nature vs. Nurture vs. Epigenetics
I watched a Ted Talks done by geneticist and doctor Courtney Griffin. She
talks about how she became very interested in Epigenetics after she became
pregnant with twins. She talks about when raising children it’s usually thought that
nurture vs. nature is what molds people into who they are. With identical twins we
notice that once child can have diseases like autism, bipolar disorder and asthma
while the other does not. Instances like these are caused by a third factor besides
nurture and nature, this is Epigenetics (Griffins). I wanted to learn more about
epigenetics and it’s effect on our lives.
Let’s break the term epigenetics down. “Epi…” means on top of and
“…Genetics” meaning your genes, so Epigenetics literally means on top of your
genes. All of our DNA can stretch to be 6 feet long, so it has to be wrapped around
itself many times and then the DNA strands are wrapped around proteins called
histones. On top of all of these things are chemical tags called epigenetic tags, which
sit on our chromatin and tell it to compact inactive genes making them unreadable
and uncompact active genes making them readable (The Epigenome at a Glance).
Our DNA code will always stay the same throughout our entire life. The epigenome
can change things though. Different chemical tags can active from things such as diet
and stress and during our development in the fetus. Different genome strands will
unwrap and become active and others will wrap up and become inactive in response
to what happens in our lives.
The best example we currently have to show how epigenetics works is
identical twins. You could separate them at birth and put them together 30 years
later and they would turn out to be very different people. If you looked at their DNA
they would still both be identical. This can be explained in a video Hank Green does
on his YouTube channel SciShow about Epigenetics “If your gnome was a paragraph
all of the letters would be in the exact same order…the letters are in the same order,
but the spaces and punctuation are in different places, completely changing the
message of the paragraph.” (Green)
For example:
My favorite flavor Hot Pocket by far is ham and cheese. I’m not sure what to
make of this “Limited Edition” Spicy Hawaiian Style Pizza. But I’ll try almost
anything once!
Has a very different tone and meaning than:
My favorite flavor Hot Pocket by far is ham. And cheese I’m not sure what to
make of. This “Limited Edition” Spicy Hawaiian Style Pizza? But I’ll try, almost.
Anything! Once!
So in the separated twins example these two people have been going through
life experiencing different things. Their environments are differing, what they are
exposed to is different. With these differences the different chemical tags will cause
the epigenome to wrap or unwrap different genes and then the twins start to
become different in more ways, while still being genetically identical.
Epigenetics has a huge effect on developing children. Things that a pregnant
mother experiences can be laid down as epigenetic marks that effect the fetus.
Animal studies have shown that a high fat diet can later cause tumors in their
offspring. A lack of vitamins can cause things like heart disease and obesity in
offspring. Smoking during pregnancy has shown to cause children to have asthma.
These things show you why pregnant women are so particular about their diets, so
they can create the best possible outcome for their children. A great example of the
effect on offspring is the study of mice and the Agouti Gene. All mammals are born
with a gene called Agouti. With mice if that gene is unmethylated then the mice grow
to be big fat and yellow, and they can get diseases like cancer and diabetes. If the
mother is fed a diet that effects the epigenetic marks and turns off the Agouti Gene
so her children will be born skinny, brown and healthy (Nutrition and the
Epigenome).
One theory says that this goes past just passing down epigenetic marks from
a mother to her child. Studies have shown that epigenetics marks can be transferred
through many generations, if the marks are put down on our sperm or eggs. A longterm study in Sweden and England showed that boys who ate too much and smoked
while their sperm was developing would have sons and grandsons with shorter
lifespans (Griffins).
Epigenetics doesn’t just effect us during birth or while we are developing. It
can happen our whole lives as our brains develop. Things like loads of stress can
cause you to get depression and other mood disorders. More studies in mice show
that environmental enrichment correlates with your ability to learn and memorize
things. Things like abuse and smoking can cause psychopathy and suicides
(Griffins).
They good thing about epigenetics is that things can always be reversed. We
know that cancer is caused by epigenetics marks. We have genes in our bodies that
are tumor suppressors, but if silencing epigenetics marks start to accumulate then
this can be turned off. Because we know this there are medicines starting to be
developed to reverse this and turn the genes back on (Griffins).
I have diabetes and it is very interesting to me that the work on therapeutic
approaches are showing great promises in reversing the epigenetics of the disease
and the genes can go back to their original states (Stankov). Maybe in the future
someone will figure out how to cure diabetes by using epigenetics and the reversing
of genomes. Epigenetics is very fascinating, it’s something that get’s overlooked but
is a huge part of who we are.
Work Cited
Griffins, Courtney. " Epigenetics and the Influence of our Genes.” YouTube. Ted Talks, Feb 23,
2012. Video. Day Nov 18, 2014.
Hank, Green. " Epigenetics.” YouTube. SciShow, Jan 22, 2012. Video. Day Nov 25, 2014.
"The Epigenome at a Glance." University Of Utah Health Sciences, 22 May 2012.
Web. 23 Nov. 2014.
"Nutrition and the Epigenome." University Of Utah Health Sciences, Web. 20 Nov.
2014.
Stankov, Karmen, Damir Benc, and Dragan Draskovic. "Genetic and Epigenetic
Factors in Etiology of Diabetes Mellitus Type 1." PEDIATRICS. 13 Aug. 2013.
Web. 29 Nov. 2014.