person to you, which is crazy!

But it's true. Anyway,

So you have this clone or twin or what have you, and your parents decide?

that it's too much trouble to keep both of you

And so they give your clone to a kind of sketchy traveling circus. Now

I know your parents probably wouldn't actually do this, but just roll with me for a minute.

So for the purposes of this example let's just say that you grew up living a normal suburban

American life while 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 and bearded ladies. And let's say you guys are 50 years old, whatever, you get together and have some lunch.

So you sit in there across the table from your clone.

What do you think you see? Well for starters,

Clone probably has a tattoo on its face.

And if Clone had stayed in the circus Clone probably, you know, professionally rides a unicycle

over a tightrope, so Clone is probably in pretty good shape. But then again Clone

probably smoked cigarettes and

probably was malnourished as a child so might be slightly shorter than you. By the same token, let's say that you've been eating sonic tater

tots five days a week since

1992 so you're looking a little bit tubby. Plus, you spent the last 20 years at a really stressful job that puts you at risk

for all kinds of weird health complications. So at 50, you and Clone would probably look pretty different from one another.

But it turns out you don't just look different. You actually have become

different. Now, if some scientists looked at your genetic code

they would say that your DNA was still exactly the same as that other person. That is to say, if your

Genome is a paragraph all of the letters would be in the exact same [word]

But on another level there would be a huge difference and if we extend this metaphor

We can say that the letters are in the same order

But the spaces in the punctuation are all in different places of course completely

Potentially changing the message of that paragraph the study of this genetic punctuation that I'm talking about is called epigenetics which literally means

Above genetics the epigenome doesn't change your DNA

But it decides how much or whether some genes are expressed in different cells in your body?

Epigenetics looks at what happens to your genes over the course of your life and whether those

changes could be passed down to your children or even your grandchildren

So here's the way epigenetics works you have billions of cells in your body and they each contain

Your dna the same exact blueprint of your genetic code

But just because they have the DNA it doesn't mean that they know what to do with it

They need outside instruction from these little carbon and hydrogen

Compounds called Methyl groups the way these Methyl groups control the genome is by binding [to] a gene and saying do not

Express this Gene the Methyl groups bind

Differently to your genome and a skin cell versus say a tongue cell or an eyeball cell and that is one of the ways that

A cell knows that hey, I'm the skin cell or hey. I'm an eyeball cell hey

I'm a muscle Cell. In addition to Methyl groups epigenetics is also controlled by

Histones which are proteins that are basically the spools that DNA winds itself around histones can change how tightly or loosely?

The DNA is wound around them if they're more loosely wound the genes can express more and if they're more tightly round than they express

Less so whereas the Methyl groups are more like a switch the histones are more like a knob

Every cell and your body has a distinct methylation and histone pattern and that is what gives

Every cell its marching orders think of your genome the DNA is the actual hardware of the computer

While the

epigenome is more like the software which tells the hardware what to do the genome is what's going to be doing all the work but

the epigenome is going to be telling it what to do so the hardware of your DNA is going to be the same throughout your

Entire life, but these epigenetic tags do change throughout your life

And they decide what genes get expressed or not. Now epigenetic information in a cell?

Isn't permanent it can change throughout your life, and it can be hereditary

And it can change over time especially when your body is going

Through a lot of changes like say during puberty a bunch of Methyl groups kick in they're like okay

So you guys over here? You're gonna have [to] start growing hair, and you guys over here

I really need you [guys] to get behind giving this guy's some really horrible

Acne or like when you get pregnant which hopefully I won't but when you do your epigenome has to be like [alright] guys

[everything's] about to get a whole lot bigger in here

And we're gonna have to pass something the size of like a miriam Webster's dictionary through that little pipe over there

So let's get this thing done, but it's not just these dramatic times when the epigenome is changing

It changes suddenly throughout our entire lives

[and] it changes based on a lot of environmental factors like what we do what we eat

What we smoke and how stressed out?

We are in a daily basis scientists have found that things like a bad diet can actually lead to Methyl groups

Binding to the wrong place and making mistakes and with those bad instructions cells become

Abnormal and become a disease and then basically all hell breaks loose

And you get cancer or something epigenetics is a very young science though. We've known about the epigenome since the 1970s

It's only in the last 20 [years] that we've even known what

Effect these epigenetic tags are having on our DNA and even after they got all that

business straight

Scientists still thought that all of our epigenetic tags were stripped off of our genome before they were passed on to our children

So if you started smoking 10 packs a day when you were 10 years old that would certainly be a horrible health decision for you

But you wouldn't necessarily be harming your unborn children in any measurable way however the thinking on [that] is changing pretty rapidly

because it's true that a [lot] even most of the

Epigenetic information from a parent is stripped off of the embryos genome in the first few days and fresh ones are created

Specifically for this new person however some [of] these tags get stuck on the genome and are passed down from generation to generation

[and] it just so happens that the more they study this the more it looks like bad

Epigenetic information is being passed from generation to generation

[and] this is a whole new way to think about how we pass information between generations your grandmother was making dietary decisions

that affect you today as we experience all these new strange epidemics diabetes autoimmune

disorders cancers that weren't appearing in Previous generations

It's starting to look like these may be caused by epigenetic information passed down from our parents

I know it's such an unbelievable Buzzkill

there is no point in our lives when we can do anything without guilt anymore [the] discovery that the

environmental Factors the parent experiences can be passed down from generation to generation was sparked in the

1980s and this happen when some scientists were looking at the birth and death records of some people who lived in [nineteenth-century]

Sweden as is a weird place to find a genetic revolution, but there it is wasn't just any place in Sweden

It was in Norrbotten. Which is the Northernmost County in Sweden

Which is literally in the arctic circle and despite the fact that [norrbotten] was literally the worst place

you could possibly choose to live in sweet there were some people living there in the

1800s and they were completely cut off from the rest of the world let me clarify these people were

Isolated like if they didn't have a good crop year people died no, it wasn't ideal

But you know they didn't ask me my opinion

So I'm not giving it

So anyway these people subsisted entirely on what they grew when the animals that they raised and like I said

Sometimes they starved but sometimes they had huge bountiful years of plenty and what happened people totally went ape crackers

I mean of course they did because they were so freakin hungry

and then all of a [sudden] there was all this damn food everywhere anyway there was a public health specialist who was looking at the

effects of the people who grew up in the really bad

Starving periods of time versus the people who grew [up] in the eat all you can at the smorgasbord

Years you might already be guessing what they found out people [who] went from relatively slim pickins to feed your face until you have to

Barf and then do it all over again in a single season those people got an average of six years sooner than [they're] starved out

Counterparts, and you know it sucks, so do their kids instead of their kids kids who epigenetics

So of course now we all know and we're all going to stop doing unhealthy things

starting today

Unless the damage is already done the damage is

almost certainly already done, but hey

epigenetics brings good tidings along with bad ones

for instance

We now know that certain types of cancer are caused by misplaced epigenetic tags and scientists are now developing drugs that can

Silence the bad genes that were supposed to be turned off in the first place

additionally until recently we thought

That genes were the end all and be all of who you got to be they were your blueprint and you couldn't escape them this

Outlook is [not] just kind of depressing and also alludes to a yucky sort of social prejudice because when you look at Data without considering

Social and epigenetic factors it might look like people with less money are less intelligent

So just like 15 years ago there were scientists saying things in public mind you like some people just have good genes for

Intelligence and it just so happens that the poor people don't all it's so sad too bad poor people

But you have bad genes [well] turns out that that is not even a little bit true

Not only are there a huge variety of social factors that affect

How well people do on intelligence tests that a genetic trait is also, not just a product of genes

it's also a product of environment any one person's genome was determined by any number of

Is made by any number of their ancestors and right now you are making decisions that are going to affect [people] who are alive?

long after you were Dead

[no] pressure or anything and so I'm glad you've watched this because when you and your clone are in your 60s

And you sit down have lunch, and he brings his son and his son has a tattoo on his face

He did not inherit that from you. This is Hank Green from the Scishow. We hope you learned something.