What is epigenetics? - Carlos Guerrero-Bosagna
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0:07 - 0:09Here's a conundrum:
-
0:09 - 0:12identical twins originate
from the same DNA, -
0:12 - 0:14so how can they turn out so different
-
0:14 - 0:18even in traits that have a significant
genetic component? -
0:18 - 0:22For instance, why might one twin
get heart disease at 55, -
0:22 - 0:25while her sister runs marathons
in perfect health? -
0:25 - 0:28Nature versus nurture
has a lot to do with it, -
0:28 - 0:33but a deeper related answer can be found
within something called epigenetics. -
0:33 - 0:36That's the study of how DNA interacts
-
0:36 - 0:39with the multitude of smaller molecules
found within cells, -
0:39 - 0:43which can activate and deactivate genes.
-
0:43 - 0:46If you think of DNA as a recipe book,
-
0:46 - 0:50those molecules are largely what determine
what gets cooked when. -
0:50 - 0:54They aren't making any conscious
choices themselves, -
0:54 - 0:58rather their presence and concentration
within cells makes the difference. -
0:58 - 1:00So how does that work?
-
1:00 - 1:06Genes in DNA are expressed when they're
read and transcribed into RNA, -
1:06 - 1:11which is translated into proteins
by structures called ribosomes. -
1:11 - 1:15And proteins are much of what determines
a cell's characteristics and function. -
1:15 - 1:22Epigenetic changes can boost or interfere
with the transcription of specific genes. -
1:22 - 1:25The most common way interference happens
is that DNA, -
1:25 - 1:27or the proteins it's wrapped around,
-
1:27 - 1:30gets labeled with small chemical tags.
-
1:30 - 1:34The set of all of the chemical tags
that are attached to the genome -
1:34 - 1:35of a given cell
-
1:35 - 1:37is called the epigenome.
-
1:37 - 1:42Some of these, like a methyl group,
inhibit gene expression -
1:42 - 1:44by derailing the cellular
transcription machinery -
1:44 - 1:48or causing the DNA to coil more tightly,
-
1:48 - 1:50making it inaccessible.
-
1:50 - 1:53The gene is still there, but it's silent.
-
1:53 - 1:56Boosting transcription is essentially
the opposite. -
1:56 - 2:01Some chemical tags will unwind the DNA,
making it easier to transcribe, -
2:01 - 2:05which ramps up production
of the associated protein. -
2:05 - 2:08Epigenetic changes can survive
cell division, -
2:08 - 2:12which means they could affect
an organism for its entire life. -
2:12 - 2:14Sometimes that's a good thing.
-
2:14 - 2:16Epigenetic changes are part
of normal development. -
2:16 - 2:20The cells in an embryo start
with one master genome. -
2:20 - 2:22As the cells divide,
some genes are activated -
2:22 - 2:24and others inhibited.
-
2:24 - 2:27Over time, through this epigenetic
reprogramming, -
2:27 - 2:29some cells develop into heart cells,
-
2:29 - 2:32and others into liver cells.
-
2:32 - 2:35Each of the approximately 200
cell types in your body -
2:35 - 2:37has essentially the same genome
-
2:37 - 2:40but its own distinct epigenome.
-
2:40 - 2:43The epigenome also mediates
a lifelong dialogue -
2:43 - 2:46between genes and the environment.
-
2:46 - 2:49The chemical tags that
turn genes on and off -
2:49 - 2:52can be influenced by factors
including diet, -
2:52 - 2:53chemical exposure,
-
2:53 - 2:55and medication.
-
2:55 - 2:59The resulting epigenetic changes
can eventually lead to disease, -
2:59 - 3:04if, for example, they turn off a gene
that makes a tumor-suppressing protein. -
3:04 - 3:08Environmentally-induced epigenetic
changes are part of the reason -
3:08 - 3:13why genetically identical twins
can grow up to have very different lives. -
3:13 - 3:16As twins get older,
their epigenomes diverge, -
3:16 - 3:21affecting the way they age
and their susceptibility to disease. -
3:21 - 3:25Even social experiences can cause
epigenetic changes. -
3:25 - 3:26In one famous experiment,
-
3:26 - 3:30when mother rats weren't attentive
enough to their pups, -
3:30 - 3:34genes in the babies that helped them
manage stress were methylated -
3:34 - 3:36and turned off.
-
3:36 - 3:39And it might not stop
with that generation. -
3:39 - 3:43Most epigenetic marks are erased
when egg and sperm cells are formed. -
3:43 - 3:48But now researchers think that some
of those imprints survive, -
3:48 - 3:52passing those epigenetic traits
on to the next generation. -
3:52 - 3:55Your mother's or your father's
experiences as a child, -
3:55 - 3:57or choices as adults,
-
3:57 - 4:00could actually shape your own epigenome.
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4:00 - 4:03But even though epigenetic changes
are sticky, -
4:03 - 4:05they're not necessarily permanent.
-
4:05 - 4:08A balanced lifestyle that includes
a healthy diet, -
4:08 - 4:09exercise,
-
4:09 - 4:11and avoiding exposure to contaminants
-
4:11 - 4:15may in the long run
create a healthy epigenome. -
4:15 - 4:18It's an exciting time to be studying this.
-
4:18 - 4:20Scientists are just beginning
to understand -
4:20 - 4:25how epigenetics could explain mechanisms
of human development and aging, -
4:25 - 4:26as well as the origins of cancer,
-
4:26 - 4:28heart disease,
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4:28 - 4:29mental illness,
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4:29 - 4:30addiction,
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4:30 - 4:32and many other conditions.
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4:32 - 4:36Meanwhile, new genome editing
techniques are making it much easier -
4:36 - 4:41to identify which epigenetic changes
really matter for health and disease. -
4:41 - 4:44Once we understand how our epigenome
influences us, -
4:44 - 4:47we might be able to influence it, too.
- Title:
- What is epigenetics? - Carlos Guerrero-Bosagna
- Description:
-
View full lesson: http://ed.ted.com/lessons/how-the-choices-you-make-can-affect-your-genes-carlos-guerrero-bosagna
Here’s a conundrum: Identical twins originate from the same DNA ... so how can they turn out so different — even in traits that have a significant genetic component? Carlos Guerrero-Bosagna explains that while nature versus nurture has a lot to do with it, a deeper, related answer can be found within something called epigenetics.
Lesson by Carlos Guerrero-Bosagna, animation by Chris Bishop.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 05:03
Jessica Ruby edited English subtitles for How the choices you make can affect your genes - Carlos Guerrero-Bosagna | ||
Jessica Ruby approved English subtitles for How the choices you make can affect your genes - Carlos Guerrero-Bosagna | ||
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Jessica Ruby edited English subtitles for How the choices you make can affect your genes - Carlos Guerrero-Bosagna | ||
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