Name: 【TEDx】Epigenetics and the influence of our genes | Courtney Griffins | TEDxOU
Uploaded: 2015-11-16T05:17:41.000Z
Duration: 18 min 41 s
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Nine years ago, I found myself in a doctor's office, contemplating

the nature versus nurture debate from a fresh perspective.

You see, I had been trained as a geneticist

and seeing the profound consequences in a lab setting

more on the nature, or the genetic side of the debate.

But, as my doctor revealed to me that I was pregnant with identical twins,

I realized that my convictions were about to be put to the test.

For starters, we had not budgeted on two daycare bills at once.

So I have half-jokingly started to wonder what would be the consequences

maybe, if we just sent one twin to daycare

and maybe just kind of tuck the other one in my office drawer during the workday.

Despite their identical DNA, I somehow doubted

that things would turn out all that well for the twin in the office drawer.

Identical twins have had a profound impact

on scientists' understanding of nature and nurture.

Studies on identical twins who were separated at birth

and raised in separate households have helped us understand

different traits that are more affected by nature, or DNA,

For example, some traits, like IQ or criminal tendencies,

are more affected by your DNA than the house that you grew up in.

On the other hand, other traits, like depression in men,

or your preference for a particular political party,

are more influenced by your environment than by your genes.

What about identical twins who are raised in the same home environment?

Their nature and their nurture are almost the same.

And yet, any parent of identical twins, myself included,

can quickly point out differences in their children.

One twin may have more of a preference for certain types of foods,

or may have more aptitude for a certain sport or musical instrument.

And sometimes, health differences can arise in these children.

For example, there are reports of autism,

arising in one twin at a young age while the other one remains unaffected.

given that the DNA is the same in these children?

And for the large part, their home environment has been the same too.

Well, it turns out that some of these differences can be explained

by a third, very powerful influence on our lives, besides nature and nurture.

I'm going to talk to you today about what epigenetics is

and how it impacts your life, even if you're not an identical twin.

Before we talk about epigenetics, we need to consider our DNA

and how it fits into our cells because, believe it or not,

of the 50 trillion or so cells in your body,

each one contains about six linear feet of DNA.

If we were to stretch it out, it would be about as tall as a pretty tall man.

So how in the world do we fit that amount of genetic material

into something the size of a cell nucleus,

Well, the answer is that we do it by wrapping our DNA

around clusters of proteins called histones.

You can think of histones like molecular spools.

There are about 30 million of these spools in each of your cells.

such a tremendous amount of DNA into a small space.

We call this combination of histones and DNA, chromatin.

this tremendous packaging problem that the cell has,

This is one of DNA accessibility because keep in mind

that the functional units of DNA are actually the genes encoded in it.

There are what tell the cell what to do and who to become

and yet, when these genes are tightly compacted into a chromatin structure,

the cell in unable to read them, they might as well not even be there.

'Epi' meaning 'on top of' and 'genetics', your 'genes',

literally refers to a set of instructions

that sits down on top of our DNA and our histones.

Epigenetic marks are small chemical tags which sit down on our chromatin

and can help instruct it whether to compact or decompact.

how the cell reads the underlying genes encoded in the DNA.

some Epigenetic marks, shown here in red, can help condense chromatin.

When they do this, they obscure the underlying genes,

preventing the cell from being able to read them.

Other Epigenetic marks, shown here in green,

When they do this, the gene becomes accessible to the cell,

the cell is able to read it and turn it on.

These types of Epigenetic marks are profoundly influential to our biology.

what is it that makes our cells different from one another,

what makes them look and behave differently,

what is it that makes a muscle cell, for instance,

After all, these cells contain exactly the same DNA

but it's their Epigenetic instructions that help tell them

which genes to turn on and which ones to turn off.

With those different genes at play, these can become very different cells.

You might be wondering when does all this Epigenetic information

The answer is that much of it happens during our embryonic development.

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【TEDx】Epigenetics and the influence of our genes | Courtney Griffins | TEDxOU

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develop

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neuron