So say you have a clone or a secret identical twin because you know that a twin or clone is a genetically identical 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.

Danny Hutson

100 thoughts on “Epigenetics

  1. I heard a Swiss geneticist who went back into his own ancestry; which was in the Alps, and his ancestors also got snowed in every winter, sometimes starving a month or two before the spring thaw. The church kept good records. He discovered that the epigenetic benefits of starving for a couple of months during winter reduced all the chronic illnesses significantly, and extended life; a similar result discussed in this clip. In addition he mentioned that an ideal time for reaping the healthy benefits of a couple of months of starving was during adolescence, and an adolescent who starved would pass the benefits down for two generations.
    He did not mention that starving is always bad for toddlers and babies. Too little food leads to brain damage when one is that young.
    He did not mention that most (maybe all) hunting gathering cultures had puberty ceremonies in which adolescents and teens fasted for a month or two. Maybe those hunting gathering cultures, through trial and error, know some stuff we are ignorant about . . . . eh? (Trial and error; more than 200, 000 years of hunting gathering compared to 30, 000 years of agriculture and civilization.)

  2. The face tattoo and smoking analogies are funny but some people are not knowledgeable enough to make the connection and would actually think that genes compel us to get face tattoos. Epigenetics would result more in traits like slower metabolism. It's best if you use realistic examples otherwise you'll feed misinformation.

  3. Hank, first of all, I love your videos and energy. Although you are correct in saying there are hereditary changes in the epigenome (these are called imprinting marks), the debate on the impact of trans-generational epigenetic inheritance affecting human traits is still ongoing. Some of the studies you are presenting here as solid evidence are very flawed and confounded and should not be taken as final proof (https://www.cell.com/action/showPdf?pii=S0092-8674%2814%2900286-4).
     This is a very new and "dangerous" field of research, because it's very prone to misinterpretations like this. This being said, I highly doubt Youtube to be the right platform to discuss this, but taking into account this has around 2 million views just thought I'd give it a try…

  4. If the father smokes and his wife is pregnant, is there more of a chance that the baby is predisposed to become a smoker? What about if the father quits smoking before making a baby?

  5. Wow. Epigenetics could vindicate me from an answer I got wrong in Biology class, BACK IN 1975! The teacher asked the following question: if you cut off the tail of a mouse generation after generation, would future generations of this mouse be born without tails? I raised my hand for  – Yes.  We were told that was the wrong answer. Fast forward to 2019. The experience of getting a tail cut off could be passed onto future generations and tail genes could be suppressed via epigenetics. So apparently my thinking was 44 years ahead of it's time. Can I receive a Nobel Prize retroactively?

  6. I like this old Hank and his mode of presentation. Not that I don't like the current one but this older one is more laid back. And … darker

  7. truly an interesting video, this explains why my twin brother looks very different to me now: we have very different personalities and obviously have lived through different experiences. Although our genes are the same, they are expressed differently.

  8. People with less money ARE STATISTICALLY less intelligent. And genetically less intelligent. Statistically. The contrary would be highly inconsistent.

  9. It's funny because wanting a face tattoo is a learned trait and not something that is passed down through the genes.

  10. Interesting. 7 years old video! I have been watching your newer videos but didn’t know you started more than 7 years ago. You sound exactly almost the same but better now.

  11. put a hammer in each of his hands so he can beat himself on his head It will feel good when he stops !!!!

  12. Excellent presentation. But, I cannot agree with you that only now all these diseases are showing up. Its just information technology era.

  13. Imagine if you will.

    I consumed gmos which may be corrupted or have gaps and then twenty years later I am told that I have a DNA disease and my stomach feels like it is going to explode; ironically the gmos plant also kills whatever insect eats it by making the insects stomach feel like it is going to explode. I am told that I have a DNA disease and that I am going to be very sick and over time they may have to cut some of my intestines out, and I could end up with a bag attached to my stomach.

    So, I am wondering about my damaged DNA; if I had many children would they also have a small chance that their DNA would have the knowledge of my illness? Or is there a chance that one of the children would have my autoimmune disease because DNA never forgets?

  14. "Right now you are making discussions that are gonna æffect long after you are dead"
    Laughs in infertility
    Sounds like I got a free pass to hedonism lol.

  15. Could it also be that environmental factors like poverty or famine tend to lend towards fewer/less effective coping skills, and it is the lack of positive coping skills (in conjunction with prevalence of negative coping skills) which increases one’s propensity to make bad/unhealthy decisions, and it is learned behavior rather than some ill-defined genetic contagion, that is to blame for the inter-generational similarities in health outcome? Forgive the run-on sentence, but wouldn’t Occam’s razor Favor the behavioral hypothesis?

  16. Now I see the error of my ways, I will change them right now for the benefit of the human race. I feel like fried chicken whiskey barbiturate smokin' what, wake up. she's pregnant. Oh well.

  17. Came out in 2012. It’s now 2019. In the past year, I’ve hear upwards of 10 descriptions of epigenetics. This is the first one to explain it correctly.

  18. This was the end of the nature vs nurture debate, the result? Checkmate nature. Nurture wins. look into the dutch hunger babies, Nature lost that debate hands down.

  19. The fact that the Iceland people's future generations get sick at an equal rate is only relevant if the new generation ate very healthy, and then still got sick at the same rate. That is not the case, but you implied it strongly. Heart attacks will be rare when anyone eats a specific diet which is good for heart health. IT has been proven through the Dean Ornish diet, Pritikin, and many others. I'm currently on the Mcdougall diet and although I don't have health problems in my family like parents, grandparents, I still lowered my LDL bad cholesterol from 120 to 65. It will work just the same for virtually all people who has parents that were sick.

  20. Interesting, yet underdeveloped and fraught, area of research. We must endure the fad-driven, exaggerated, and plainly erroneous claims of epigenetic influences, including the likelihood, intensity, duration, and heterogeneity, of its impact on genetic expression.

  21. So could this mean, the longer a couple waits to have children, the more tarnished their genes become before passing them to their offspring?

  22. Wow watching this show has made me realize that Hank Green has turned into a robot these days. poor guy .no offense robots.

  23. So you're sitting there, across the table from your clone–what do you think you see? Well, for starters, your clone is really, really small. He fits under a glass dome probably meant for a table clock.

  24. Serious question here: Genetics would not explain lower income populations with lower intelligence, but epigenetics might?
    If one is born into a part of the culture in which academic performance / education is not as highly valued or encouraged, this could affect one's epigenetics. And that can get passed down, generation after generation.
    Am I interpreting this information correctly?

    Also: "tattoo," not "tatoo."

  25. Whoa HUUUUUUGE oversight at 04:54. Effect with an E is most definitely NOT the same thing as affect with an A.
    Effect (noun) : result, outcome, consequence
    Affect (noun) : appearance or impression
    Effect (verb) : to bring about
    Affect (verb) : to influence

    One effect of changing your affect can be that you effect change in how you affect people.

  26. it's actually simple. you get half your flesh from two people. part of the flesh is the brain. in the subconscious for lack of a better world all of the experiences of the two parents are still there. Then you have your conscious mind which has its own experience. It's the reason people think they reincarnate. go back several generations before breeding in other words.

  27. hey mr. Science did you know that there is a point.. 08,30 min.. where all your desperately trabsparent pc-fashionable anti-scientific virtue-signalling just defeats your whole object here. If you can't stand scientific realities what are you doing making this show? Get off!

  28. So would epigenetics only affect/show-up in our offspring? Or is it possible to use epigenetics during childhood to affect our CURRENT genes?

  29. I predict this plucky young lad will one day go on to become someone, in the youtuber community—if he just shaves off that chin fungus.

  30. Does this also mean that the live experiences of slaves are in some way expressed by their descendents? I would love to see a segement about this.

  31. Optimize your body for YOUR benefit not your government machine's DO NOT ALLOW your home system to influence your gene expression to it's own benefit

  32. Epigenetics in the Word of God

    The Lord is longsuffering, and of great mercy, forgiving iniquity and transgression, and by no means clearing the guilty, visiting the iniquity of the fathers upon the children unto the third and fourth generation.
    Numbers 14:18 KJV

  33. I sometimes blame my awful immune system on epigenetics, then continue to eat junk food and not exercise. Sorry future offspring! I'll try to do better. Also, my next ASMR video will be on epigenetics, so swing by if you're interested in science, history, and asmr 🙂

  34. Epigenetics was first discovered by JC Willis in the 1890s. https://en.wikipedia.org/wiki/John_Christopher_Willis . . He called it the "Age and Area Hypothessis" as he showed that plants were passing environmental adaption between generations without any effect of natural selection. It's just the name Epigenetics was created much later.

  35. stop eating meat, dairy, eggs, bad oils. It not only gives you cancer and erectile dysfunction and diabetes, but it also does that to your offspring, babies are literally being born with atherosclerosis.

  36. "We are all better people in the future" says Dan Arielly, the Duke University professor who wrote "predicatbly irrational" a great book- so Hank, can you do a few videos on how to become a better version of ourselves now? (Factoring in the people with depression and anxiety and 4 kids!) <3

  37. Thanks for covering the bioethics part at the end. There's a lot of ways this could be misinterpreted and used for bad things. It's been done often enough before.

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