Sociology 1010
Epigenetics 

JJJ

Male Speaker:   Say you have a clone or a secret identical twin.  You know a twin or a clone is a genetically identical person to you.  Crazy, but true.  Anyway, you have this clone or twin.  Your parents decide it is too much trouble to keep both of you.  They give your clone to a sketchy traveling circus.  

Roll with me.  Say you grew up living a normal suburban life.  Your clone grew up with less stability and less access to nutritious food and less education, but more exercise and more access to sword swallowers.  

Say you guys are 50 years old.  You get together and have lunch.  What do you see?  For starters, the clone has a tattoo on his face.  If the clone had stayed in the circus, the clone was personally riding a unicycle.  Then again, clone probably smokes cigarettes and was malnourished as a child and might be shorter than you.  

By the same token, say you have been eating Sonic tater tots five days a week since 1992 so you are a bit chubby.  And you work at a high stress job so you're at risk for all kinds of weird health complications.  

At 50, you and clone would look different from one another.  It turns out that you don't just look different.  You have become different.  If scientists looked at your genetic code, your DNA would be exactly the same.  That is to say, if your genome is a paragraph, all the letters would be in the same order.  On another level, there would be a huge difference.  We can say the letters are in the same order, but the spaces and punctuation are all in different places, completely changing the message of that paragraph.  

The study of this punctuation is called epigenetics.  This means above genetics.  The epigenome doesn't change your DNA, but it decides how much or whether different cells are expressed in your body.  Epigenetics looks at what happens to genes over the course of your life and whether those changes can be passed to your children or grandchildren.  

This is how epigenetics works.  You have billions of cells in your body, and they each contain the same blue print of your genetic code.  

Just because they have the same DNA doesn't mean they know what to do with it.  They need outside instruction from carbon hydrogen compounds called methyl groups.  The way they control the genome is by binding to a gene and saying: "do not express this gene."  They bind differently to a tongue cells or an eye ball cell.  That's one of the reason why a cell knows what it is.  Epigenetics is also controlled by histones, proteins that are the spools that DNA winds itself around.  

[1:03.]  

Histones can change how tightly or loosely DNA is wound around them.  If they are loosely wound, the genes can express more and vice versa.  The methyl groups are a switch.  The histones are a knob.  

Every cell in your body has a distinct methylation and histone pattern.  That is what gives your cells the marching orders.  The DNA is the hardware of a computer.  The epigenome is software.   The genome does the work and the epigenome tells it what to do.  The hardware is the same throughout your life, but epigenetic tags do change throughout your life and they decide what genes get expressed or not.  

Epigenetic information in a cell isn't permanent.  It can change throughout your life and can change during things like puberty.  

"You guys have to start growing hair."  "You guys give this guy some horrible acme."  Or when you get pregnant.  The epigenome goes: "OK, guys.  Everything is going to get bigger in here.  We're passing something the size of a dictionary through that pipe there.  Let's get it done."  

It isn't just these dramatic times where the epigenome changes.  It changes subtly throughout our lives through environmental factors like what we do, eat, smoke, and how stressed out we are.  

Scientists have found that things like a bad diet can lead to methyl groups binding to the wrong place and making mistakes.  With those bad instructions, cells become abnormal and become a disease.  Then all hell breaks loose and you get cancer.  Epigenetics is a young science, but we have known about it since the 1970s.  It's only in the last 20 years that we have known what effects these tags have on our genome.  

Even after we got that straight, scientists still thought that our epigenetic tags were stripped off our genome before they were passed on to our children.  If you started smoking 10 packs a day when you were 10, that would be a horrible decision for you, but you wouldn't be harming your children.  However, the thinking on that is changing rapidly.  

It is true that a lot, even most of the epigenetic tags are stripped off, it is also true that some tags get stuck and are passed on.  The more they study this, the more it looks like bad epigenetic tags are being passed across epigenetics.  This is a new way to think about how we pass on epigenetic information.  Your grandmother was making dietary decisions that affect you today.  

As we experience these new, strange epidemics like diabetes, auto immune disorders, and cancers that weren't appearing in previous disease, it looks like these may be caused by previous epigenetic informant passed down from our parents.  

[1:06.]  

I know.  It's an unbelievable buzz kill.  There is no point in our lives where we can do anything without guilt anymore.  

The discovery that the environmental factors a parent experiences can be passed down from generation to generation was sparked in the 1980s.  This happened when scientists were looking at death records of people who lived in 19th century Sweden.  This is a strange place to find a genetic revolution, but there it is.  

It was just any place, it was Norrbotten, which is the northern most county in Sweden, which is literally in the Arctic Circle.  Despite the fact that Norrbotten was the worst place you could choose to live in Sweden, there were people living there in the 1800s.  They were totally cut off from the rest of the world.  I'll be clear.  These people were isolated.  If they had a bad crop year, they would have died. No, it wasn't ideal, but they didn't ask me for my opinion.   

These people subsisted on the animals they raised and what they grew.   Sometimes they starved.  Sometimes they had huge, bountiful years of plenty.  When that happened, people went ape crackers.  Of course they did.  They were so hungry and then there was a lot of food everywhere.  

There was a public health specialist that was looking at the people who lived during the starving times vs. the other years.  

You can guess what they found out.  People that went from relatively slim to pigged out.  The people who pigged out died about six years earlier and so did their kids and kids’ kids. 

Now we know.  We'll stop doing unhealthy things today, unless the damage is already done?  It's already done.  

Epigenetics brings good titles along with bad ones.  For instance, now we know that certain types of cancers are caused by misplaced epigenetic tags.  Scientists are developing drugs that can turn off the bad genes.  We initially thought that genes were the be all and end all of you were supposed to be.  

This outlook isn't also just depressing, it leads to social prejudice.  If we look at data without considering social and epigenetic factors, it might look like people with less money are less intelligent.  15 years ago, scientists were saying that: "some people just have good genes for intelligence, but not poor people.  Sorry poor people.  You have bad genes."  

It turns out that that isn't even a little bit true.  Not only are there a huge variety of social factors that affect how well people do on intelligence tests.  An intelligence trait isn't just a product of genes, also of environment.  Someone's genes are affected by many decisions of many ancestors.  

Right now, you're making genes that will affect your descendants for generations.  '

[1:09.]  

When you sit down with your clone in 50 years and have lunch.  He brings his son.  His son has a tattoo on his face?  He didn't inherit that from you.  

This is Sam from the science show.  We hope you learned something.  

[End of video.]