Transcriber: alberto perez Reviewer: Maria Coimbra
I want to tell you a story about bees.
We all know how bees live in very organized societies.
They work together for the good of the colony
and they actually divide the work between themselves.
Some of them are called foragers,
they go out from the colony to look for food.
And some of them are called nurses,
they stay in the colony taking care of it.
Both kind of bees have the same DNA, the same information that made them,
but their behavior is completely different.
And you can actually see that the information
that they use from their DNA is completely different.
There are actually some markers on top of their DNA
that is changing how this information can be used.
Now, imagine that we take away all the nurses from the colony
while the foragers are gone.
When they come back, some of them, are going to start working as nurses
not only is their behavior going to change,
but also what information they are using from their DNA.
Those markers are also going to be changing.
And what I want to tell you about today is about this new exciting research
about how those markers can affect the information on your DNA,
how they are affected by our environment and the decisions we make
and how they can influence your lives.
So let me step back for a second.
I actually got interested in DNA when I was a kid.
I was very confused.
Just imagine growing up as a red head in Spain.
I got asked quite a lot of times if I was lost in my own town.
And actually both my parents and brother have dark hair
and most of the kids in my school also had dark hair.
So I was really wondering where I came from,
if I was adopted and all those kinds of things that kids usually worry about.
So, when I actually asked my dad about it, he said: "it's all in your DNA."
And that wasn't the answer I was looking for,
but it did get me interested about DNA and how it works.
And we actually know from shows like CSI and Jurassic Park
that DNA is a unique fingerprint for each one of us,
it has all the information to make one of us.
And one of the first questions I had is: well, we are complex,
how much DNA do we actually need to make one of us?
And DNA is actually a simple molecule.
It is made up from smaller building blocks, just like LEGOs.
They are stacked on top of each other making the shape of a double helix.
The more building blocks you put, the longer and longer the helix becomes.
There are actually only 4 building blocks.
They are called A, C, G and T,
for the names of the molecules they represent.
And what's cool about them
is that the order these blocks are placed in
actually codes for information about us.
So, this information might actually look something like this.
And to you and I, this might not make much sense,
but inside of our bodies that information can be turned into something useful
for our bodies in pretty much the same way that a computer code of 1s and 0s
is used in our phones to make the apps that we use.
The complete set of instructions to make one of us
is actually 3 billion letters long.
And it is called the genome.
You can think of the genome as a library containing all the information about us.
Where each one of the books contains information about how to make one specific
thing inside of us.
And instead of having just one copy of this library somewhere inside of us,
we have multiple copies.
In fact, we have one identical copy in each one of our cells.
So that when a cell needs something, it goes to its library,
looks for the information and then uses it.
Now, there are several trillion cells inside of our body.
So if I actually take all the DNA from my cells and put it together
in a straight line, there is enough DNA to go all the way
from this room to the Sun and back, several hundred times.
So that's how much DNA there is in each one of us.
And we need some way to keep that DNA inside of us
and also make the information available to us.
Just imagine what happens whenever you take your earphones
and put them in your pocket.
When you take them out again,
they are probably going to come out like a tangled mess.
You can't use them right away.
If the same happens to our DNA, then we would die.
So we actually need a quite good mechanism to store the information.
And actually, the way this information is stored in each cell
determines what information from the DNA we can use.
So in the example from the library,
just think about different layouts of the books.
Those books that are on shelves that are very easy to access
are going to be used a lot.
Where as those that are stored far away on high shelves, they might never be used.
And this is actually good.
Just imagine cells from your eyes, heart and stomach.
They have very different needs, they need to access different information
to carry out their work.
And this is done by storing the information in different ways.
What actually controls this is something called epigenomics.
This literally means: "On top of the DNA."
And this a set of markers that act to store that information in different ways,
so that we can use different information in each one of our cells.
In the example of the bees, those markers were the ones responsible for making
the behavior of those bees be different,
They could access different information and their behavior was different.
One way to think about this markers is like punctuation marks on a text.
Just imagine the next two sentences: "Let's eat, mommy!" or "Let's eat mommy!"
They have exactly the same letters, the same words,
but the meaning is completely different just by changing a small punctuation mark.
And actually the same happens with our DNA.
Where those markers are placed
is going to affect what information our cells can use.
And this is actually good.
So just imagine, though, what happens to those markers.
They can actually be affected
by our environment and the decisions we make.
Things like stress, sun exposure, diet, smoking, exercise,...
All these things can change where those markers are placed.
Imagine, for example, identical twins.
They have exactly the same DNA but their appearance might be different.
One of them might be taller, or bulkier, or even have different eye color.
When they were initially made,
they had exactly the same DNA and exactly the same markers.
But as they go through their lives and are exposed to different environments
and different decisions, their markers appear in different places
and that makes their appearance also become different.
Not only that, but the way those markers are placed can stay for a long time.
In fact sometimes, those markers can be passed on to the next generation.
And I have an example from a northern region of Sweden.
About 200 years ago,
this region was very isolated from the rest of the world.
So what they could eat was actually affected by how good the harvest was.
If the harvest was good, those were bountiful years,
they could eat plenty of food during the whole year.
Whereas if the harvest was bad, then food would become scarce.
And of course, this scarcity or abundance of food
influenced how long these people were able to live.
But more important than that, it also affected the markers on their DNA.
And it so happens that if those markers where placed during a critical period
of their development, just before puberty,
then those markers could be passed on to their children and even grandchildren.
So, imagine what that means.
What that means is that if I'm here right now, how long I might live,
that might depend on what my grandparents or my parents where eating
during their childhood.
And that's completely different
from the way we thought about Darwinian evolution.
We thought that we have some traits that we inherit from our parents
and then they go on to the next generation.
And now we are saying that something from our environment can affect our DNA
can place some markers and affect how that information is used.
So it's a completely different point of view.
The only difference is that these changes are only temporal,
they affect one or two generations.
Whereas changes in the DNA, those are permanent.
So I've told you three stories:
one about bees, about how these markers might affect behavior.
One with twins, about how it might affect the physical appearance.
And one, the recent one, about food shortage
and how it might affect how long these people live.
And it made a difference up to 6 years in how long these people lived,
even if they never got exposed to those shortages of food.
And there is one more thing I want to talk about.
Which is what happens when these markers are placed in incorrect places.
So this might actually explain why, for example in twins,
one of them might develop a genetic disease
and the other one doesn't.
This is something that we could not explain until now,
and with these markers we can see a reason for this happening.
There is also a growing number of cancers that have been identified to happen
because of incorrect placement of those markers.
And just imagine what that can mean for the future of medicine.
Up until now, we have been targeting cancers by targeting the cancer cells,
trying to kill them.
And as you know this has huge side effects for the individuals.
What we could do now is target those markers on the DNA,
revert them to the original position,
so that those cancer cells could act like normal cells.
And this would reduce the side effects a lot.
So, this is one of the many reasons
why epigenomics has been exploding in the last years.
It's changing the whole way we are looking at DNA
and the way the information inside us is used.
It has even been featured on the cover of TIMES magazine,
saying how "DNA is not our destiny."
We might be in a future
where we are no longer determined by what the information inside us is.
We could place certain markers that change things we don't want to ever happen in us.
So all in all, this is opening a whole new world of opportunities for our future.
Thank you very much!
(Applause)