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  • 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 actually 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 was coming from, if I was adopted and all those kind 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 this 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.

  • So, 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 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 inside 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 in 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.

  • And one way to think about this markers is like punctuation marks on a text.

  • 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 are 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 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 through a long time.

  • In fact some times, 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 on how long this 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 to their grandchildren.

  • So imagine what that means. What that means is that if I'm here right now,

  • how long i might leave, 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. Where as 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 that 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 shortness 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 does not. 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 this might 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 would become like normal cells. And this would reduce a lot the side effects.

  • So, this is one of the 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 in 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!

I want to tell you a story about bees.

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B1 dna information affect imagine colony behavior

【TEDx】You can't always blame your parents: Alberto Perez at TEDxSBU

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    阿多賓 posted on 2014/01/28
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