Can Your Environment Affect Your DNA? | Epigenetics Explained — Transcript

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1. 0:11So say you have a clone or a secret identical twin because you know that a twin or clone is a genetically identical
2. 0:19person to you, which is crazy!
3. 0:21But it's true. Anyway,
4. 0:22So you have this clone or twin or what have you, and your parents decide?
5. 0:26that it's too much trouble to keep both of you
6. 0:28And so they give your clone to a kind of sketchy traveling circus. Now
7. 0:32I know your parents probably wouldn't actually do this, but just roll with me for a minute.
8. 0:34So for the purposes of this example let's just say that you grew up living a normal suburban
9. 0:39American life while your clone grew up with less stability and less access to nutritious food and less education.
10. 0:45But more exercise and more access to sword
11. 0:48swallowers and bearded ladies. And let's say you guys are 50 years old, whatever, you get together and have some lunch.
12. 0:53So you sit in there across the table from your clone.
13. 0:56What do you think you see? Well for starters,
14. 0:58Clone probably has a tattoo on its face.
15. 1:00And if Clone had stayed in the circus Clone probably, you know, professionally rides a unicycle
16. 1:04over a tightrope, so Clone is probably in pretty good shape. But then again Clone
17. 1:08probably smoked cigarettes and
18. 1:09probably 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
19. 1:15tots five days a week since
20. 1:171992 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
21. 1:23for all kinds of weird health complications. So at 50, you and Clone would probably look pretty different from one another.
22. 1:30But it turns out you don't just look different. You actually have become
23. 1:35different. Now, if some scientists looked at your genetic code
24. 1:37they would say that your DNA was still exactly the same as that other person. That is to say, if your
25. 1:43Genome is a paragraph all of the letters would be in the exact same [word]
26. 1:48But on another level there would be a huge difference and if we extend this metaphor
27. 1:51We can say that the letters are in the same order
28. 1:53But the spaces in the punctuation are all in different places of course completely
29. 1:58Potentially changing the message of that paragraph the study of this genetic punctuation that I'm talking about is called epigenetics which literally means
30. 2:06Above genetics the epigenome doesn't change your DNA
31. 2:10But it decides how much or whether some genes are expressed in different cells in your body?
32. 2:15Epigenetics looks at what happens to your genes over the course of your life and whether those
33. 2:19changes could be passed down to your children or even your grandchildren
34. 2:23So here's the way epigenetics works you have billions of cells in your body and they each contain
35. 2:27Your dna the same exact blueprint of your genetic code
36. 2:31But just because they have the DNA it doesn't mean that they know what to do with it
37. 2:34They need outside instruction from these little carbon and hydrogen
38. 2:37Compounds called Methyl groups the way these Methyl groups control the genome is by binding [to] a gene and saying do not
39. 2:43Express this Gene the Methyl groups bind
40. 2:45Differently to your genome and a skin cell versus say a tongue cell or an eyeball cell and that is one of the ways that
41. 2:51A cell knows that hey, I'm the skin cell or hey. I'm an eyeball cell hey
42. 2:54I'm a muscle Cell. In addition to Methyl groups epigenetics is also controlled by
43. 2:58Histones which are proteins that are basically the spools that DNA winds itself around histones can change how tightly or loosely?
44. 3:06The 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
45. 3:12Less so whereas the Methyl groups are more like a switch the histones are more like a knob
46. 3:16Every cell and your body has a distinct methylation and histone pattern and that is what gives
47. 3:22Every cell its marching orders think of your genome the DNA is the actual hardware of the computer
48. 3:27While the
49. 3:27epigenome 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
50. 3:33the epigenome is going to be telling it what to do so the hardware of your DNA is going to be the same throughout your
51. 3:39Entire life, but these epigenetic tags do change throughout your life
52. 3:43And they decide what genes get expressed or not. Now epigenetic information in a cell?
53. 3:48Isn't permanent it can change throughout your life, and it can be hereditary
54. 3:52And it can change over time especially when your body is going
55. 3:55Through a lot of changes like say during puberty a bunch of Methyl groups kick in they're like okay
56. 3:59So you guys over here? You're gonna have [to] start growing hair, and you guys over here
57. 4:02I really need you [guys] to get behind giving this guy's some really horrible
58. 4:05Acne or like when you get pregnant which hopefully I won't but when you do your epigenome has to be like [alright] guys
59. 4:11[everything's] about to get a whole lot bigger in here
60. 4:14And we're gonna have to pass something the size of like a miriam Webster's dictionary through that little pipe over there
61. 4:19So let's get this thing done, but it's not just these dramatic times when the epigenome is changing
62. 4:23It changes suddenly throughout our entire lives
63. 4:25[and] it changes based on a lot of environmental factors like what we do what we eat
64. 4:29What we smoke and how stressed out?
65. 4:31We are in a daily basis scientists have found that things like a bad diet can actually lead to Methyl groups
66. 4:36Binding to the wrong place and making mistakes and with those bad instructions cells become
67. 4:41Abnormal and become a disease and then basically all hell breaks loose
68. 4:44And you get cancer or something epigenetics is a very young science though. We've known about the epigenome since the 1970s
69. 4:51It's only in the last 20 [years] that we've even known what
70. 4:53Effect these epigenetic tags are having on our DNA and even after they got all that
71. 4:57business straight
72. 4:58Scientists still thought that all of our epigenetic tags were stripped off of our genome before they were passed on to our children
73. 5:04So if you started smoking 10 packs a day when you were 10 years old that would certainly be a horrible health decision for you
74. 5:09But you wouldn't necessarily be harming your unborn children in any measurable way however the thinking on [that] is changing pretty rapidly
75. 5:15because it's true that a [lot] even most of the
76. 5:19Epigenetic information from a parent is stripped off of the embryos genome in the first few days and fresh ones are created
77. 5:25Specifically for this new person however some [of] these tags get stuck on the genome and are passed down from generation to generation
78. 5:31[and] it just so happens that the more they study this the more it looks like bad
79. 5:35Epigenetic information is being passed from generation to generation
80. 5:38[and] this is a whole new way to think about how we pass information between generations your grandmother was making dietary decisions
81. 5:46that affect you today as we experience all these new strange epidemics diabetes autoimmune
82. 5:53disorders cancers that weren't appearing in Previous generations
83. 5:56It's starting to look like these may be caused by epigenetic information passed down from our parents
84. 6:02I know it's such an unbelievable Buzzkill
85. 6:04there is no point in our lives when we can do anything without guilt anymore [the] discovery that the
86. 6:10environmental Factors the parent experiences can be passed down from generation to generation was sparked in the
87. 6:151980s and this happen when some scientists were looking at the birth and death records of some people who lived in [nineteenth-century]
88. 6:21Sweden as is a weird place to find a genetic revolution, but there it is wasn't just any place in Sweden
89. 6:27It was in Norrbotten. Which is the Northernmost County in Sweden
90. 6:32Which is literally in the arctic circle and despite the fact that [norrbotten] was literally the worst place
91. 6:38you could possibly choose to live in sweet there were some people living there in the
92. 6:421800s and they were completely cut off from the rest of the world let me clarify these people were
93. 6:46Isolated like if they didn't have a good crop year people died no, it wasn't ideal
94. 6:51But you know they didn't ask me my opinion
95. 6:52So I'm not giving it
96. 6:53So anyway these people subsisted entirely on what they grew when the animals that they raised and like I said
97. 6:58Sometimes they starved but sometimes they had huge bountiful years of plenty and what happened people totally went ape crackers
98. 7:04I mean of course they did because they were so freakin hungry
99. 7:06and then all of a [sudden] there was all this damn food everywhere anyway there was a public health specialist who was looking at the
100. 7:11effects of the people who grew up in the really bad
101. 7:15Starving periods of time versus the people who grew [up] in the eat all you can at the smorgasbord
102. 7:20Years you might already be guessing what they found out people [who] went from relatively slim pickins to feed your face until you have to
103. 7:27Barf 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
104. 7:33Counterparts, and you know it sucks, so do their kids instead of their kids kids who epigenetics
105. 7:39So of course now we all know and we're all going to stop doing unhealthy things
106. 7:44starting today
107. 7:45Unless the damage is already done the damage is
108. 7:48almost certainly already done, but hey
109. 7:50epigenetics brings good tidings along with bad ones
110. 7:53for instance
111. 7:54We now know that certain types of cancer are caused by misplaced epigenetic tags and scientists are now developing drugs that can
112. 8:00Silence the bad genes that were supposed to be turned off in the first place
113. 8:03additionally until recently we thought
114. 8:05That 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
115. 8:11Outlook is [not] just kind of depressing and also alludes to a yucky sort of social prejudice because when you look at Data without considering
116. 8:17Social and epigenetic factors it might look like people with less money are less intelligent
117. 8:22So just like 15 years ago there were scientists saying things in public mind you like some people just have good genes for
118. 8:29Intelligence and it just so happens that the poor people don't all it's so sad too bad poor people
119. 8:35But you have bad genes [well] turns out that that is not even a little bit true
120. 8:40Not only are there a huge variety of social factors that affect
121. 8:43How well people do on intelligence tests that a genetic trait is also, not just a product of genes
122. 8:49it's also a product of environment any one person's genome was determined by any number of
123. 8:53Is made by any number of their ancestors and right now you are making decisions that are going to affect [people] who are alive?
124. 9:00long after you were Dead
125. 9:02[no] pressure or anything and so I'm glad you've watched this because when you and your clone are in your 60s
126. 9:07And you sit down have lunch, and he brings his son and his son has a tattoo on his face
127. 9:12He did not inherit that from you. This is Hank Green from the Scishow. We hope you learned something.