NOVA | Epigenetics
Summary
TLDRThe video script explores the concept of epigenetics, revealing how identical twins, with the same DNA, can diverge in appearance and health due to changes in their epigenome. It discusses the influence of environmental factors and lifestyle on gene expression, as demonstrated through studies on mice and twins. The script also highlights the potential of epigenetic therapy in treating diseases like cancer by altering gene instructions rather than killing cells, offering hope for disease management and prevention.
Takeaways
- đ„ Identical twins, despite having the same DNA, can exhibit different physical appearances and health conditions as they age due to epigenetic changes.
- 𧏠Our genes define who we are, but they are not the only factor; epigenetics, which can work with or against our genes, also plays a significant role.
- đ Researchers at Duke University, led by Randy Jirtle, have shown that genetically identical mice can have different physical traits based on the presence of a methyl group, which can turn genes on or off.
- đ The study of mice revealed that the epigenome, a sort of second genome, can be altered by environmental factors such as diet, affecting gene expression and potentially leading to health issues like obesity.
- đ± Epigenetic changes can be passed down through generations, meaning that what a mother or even a grandmother ate could affect the health of their descendants.
- đ§Źđż Epigenetics is the study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself.
- đ§Ș In a study of identical twins, it was found that as they age, their epigenomes can diverge significantly, especially when their lifestyles differ.
- đ§Źđ Epigenetic instructions can change during critical periods like puberty or pregnancy, which can lead to different gene expressions in cells.
- đ„ Epigenetic therapy is a new approach to treating diseases like cancer, which focuses on changing the behavior of cells by reactivating genes rather than killing them.
- đ Epigenetic drugs have shown promise in clinical trials, with some patients achieving remission without severe side effects.
- đ±đ¶ The epigenome is not only influenced by what we do but also by what our ancestors did, emphasizing the importance of lifestyle choices for future generations.
Q & A
What is the main point discussed in the video about identical twins?
-The video discusses how identical twins, despite having the same DNA, can exhibit different physical appearances and health conditions due to epigenetics, which involves changes in gene expression that do not involve alterations to the underlying DNA sequence.
What is the role of genes in determining who we are?
-Genes play a significant role in determining who we are by providing the instructions for making proteins, which are essential for the structure and function of our bodies. However, genes are not the whole story, as epigenetic factors can influence gene expression and thus our traits and health.
What is the significance of the study conducted by Duke University's Randy Jirtle on mice?
-Randy Jirtle's study on mice demonstrated that epigenetic changes can occur even in genetically identical organisms, leading to different physical characteristics such as size and coat color. This suggests that environmental factors and diet can influence the epigenetic marks on our DNA, affecting traits and potentially health.
What is the epigenetic explanation for the differences observed in identical twins as they age?
-As identical twins age, their lifestyles, diets, and environmental exposures can lead to the accumulation of epigenetic differences. These differences can result in changes to gene expression, which may manifest as physical or health disparities between the twins.
What is the epigenome, and how does it relate to the genome?
-The epigenome refers to the chemical modifications to the DNA and associated proteins that regulate gene expression without changing the underlying DNA sequence. It acts as a layer of information 'above' the genome, influencing which genes are active or silent in different cell types.
How can the epigenome be influenced by environmental factors?
-Environmental factors such as diet, exposure to toxins, and lifestyle can influence the epigenome by adding or removing chemical tags like methyl groups to DNA and associated proteins, which can turn genes on or off and affect gene expression.
What is the potential impact of epigenetic changes on human health?
-Epigenetic changes can have profound implications for human health. They can influence susceptibility to diseases, including cancer, and may also affect the health of future generations by altering gene expression in ways that are inherited.
What is the concept of epigenetic therapy, and how does it differ from traditional cancer treatments?
-Epigenetic therapy aims to modify the epigenetic marks on DNA to reactivate silenced genes or inhibit overactive ones, rather than killing the cells as in traditional cancer treatments. This approach seeks to remind cancer cells of their normal function and behavior, potentially offering fewer side effects.
How were epigenetic differences in identical twins studied in the Madrid research?
-In the Madrid study, researchers collected cells from 40 pairs of identical twins and analyzed their DNA for epigenetic modifications. They observed that the epigenomes of older twins, especially those with different lifestyles, showed more dramatic differences compared to younger twins.
What does the video suggest about the responsibility individuals have regarding their epigenome?
-The video suggests that individuals have a responsibility to consider how their actions, such as diet and lifestyle choices, can potentially alter their epigenome and that of their future generations, emphasizing the importance of making healthy choices.
What is the potential of epigenetic therapy in treating diseases like cancer?
-Epigenetic therapy holds promise in treating diseases like cancer by targeting the chemical tags that control gene expression, rather than the genes themselves. This approach can reactivate normal gene function in cancer cells, potentially leading to remission with fewer side effects compared to traditional treatments.
Outlines
đ Identical Twins: Beyond the Genes
This paragraph explores the concept that identical twins, despite having the same DNA, can exhibit different physical traits and health outcomes as they age. It introduces the idea that genes are not the sole determinants of who we are, and that epigeneticsâthe study of changes in organisms caused by modification of gene expression rather than the alteration of the genetic code itselfâplays a significant role. The narrative uses the example of mice with identical DNA but different physical appearances and health statuses due to epigenetic modifications, highlighting the work of Duke University's Randy Jirtle, who investigates how the epigenome can influence gene expression and potentially affect health outcomes, including obesity and disease susceptibility.
đŹ The Epigenetic Influence on Health and Heredity
The second paragraph delves into the impact of epigenetics on health and how it can be influenced by environmental factors such as diet. It explains the epigenome as a layer of instructions that dictate how and when genes are expressed, differentiating cell types in the body. The Madrid study of identical twins is highlighted, showing how epigenetic differences accumulate over time, especially when twins lead different lifestyles. The research indicates that these epigenetic changes can be inherited by subsequent generations, suggesting that the health of future generations could be influenced by the environmental exposures and behaviors of their ancestors.
đĄïž Epigenetic Therapy: A New Approach to Disease
The final paragraph discusses the potential of epigenetic therapy in treating diseases like cancer, which can be influenced by the silencing of critical genes. It contrasts the traditional view of cancer as a disease of broken genes with the newer understanding that epigenetic tags can be manipulated to reactivate genes and revert cancerous cells to a normal state. The narrative shares the story of individuals who have participated in clinical trials for epigenetic therapy, resulting in remission for some patients. It concludes with a call to action for individuals to be mindful of their actions, as they have the potential to positively or negatively affect their own and their offspring's epigenome.
Mindmap
Keywords
đĄIdentical Twins
đĄDNA
đĄEpigenetics
đĄGene Expression
đĄMethyl Group
đĄHistones
đĄEpigenomic Tags
đĄDisease Susceptibility
đĄClinical Trials
đĄEpigenetic Therapy
đĄGenome
Highlights
Identical twins, though sharing the same DNA, can exhibit subtle differences in appearance and health as they age.
Genes alone do not fully determine who we are; epigenetics plays a crucial role.
Epigenetics refers to changes in gene expression that can be influenced by factors like diet and environment.
Researchers at Duke University have discovered that a methyl group can modify genes, affecting traits such as obesity in mice.
The epigenome, a collection of chemical tags, can control gene expression and is considered a 'second genome'.
Epigenetic changes can be passed on as cells divide, but they are not necessarily permanent and can change during critical periods like puberty or pregnancy.
Feeding pregnant mice a diet rich in methyl groups can alter the coat color of their offspring, indicating epigenetic changes.
Environmental toxins in the diet can lead to epigenetic changes that result in health issues like obesity in the next generation.
Epigenetic studies in humans, particularly identical twins, show that epigenetic differences can accumulate over time, especially with different lifestyles.
A study in Madrid aimed to determine the epigenetic similarities and differences among identical twins of various ages.
Epigenetic changes can be triggered by what we eat, smoke, or drink, potentially leading to diseases like cancer.
Cancer can be viewed as a disease stemming from epigenetic changes rather than solely from broken genes.
Epigenetic therapy is a new approach that aims to change the behavior of cancer cells by reactivating genes, rather than killing the cells.
Clinical trials using epigenetic therapy have shown promising results, with many patients achieving remission.
While it may be easier to fix our epigenome than our genome, it is also easier to mess it up, highlighting the importance of lifestyle choices.
Individuals have a responsibility for their epigenome, which can potentially be altered and impact future generations.
Epigenetic changes offer hope for disease prevention and treatment, as they are more malleable than genetic changes.
Transcripts
you ever noticed that if you get to know
two identical twins they might look
alike but they're always subtly
different yeah whatever as they get
older those differences can get more
pronounced two people start out the same
but their appearance and their health
can diverge for instance you have more
gray hair no no I don't identical twins
have the same DNA the exact same genes
yeah and don't our genes make us who we
are well they do yes but they're not the
whole story some researchers have
discovered a new bit of biology that can
work with our genes or against them yeah
you're heavier and I'm better looking
yeah
whatever imagine coming into the world
with a person so like yourself that for
a time you don't understand
mirrors as a child when I looked in the
mirror i' say that's my sister
and my mother will say no that's your
reflection and even if you resist this
cookie cutter
existence cultivate individual Styles
and abilities like cutting your hair
differently or running
faster uncanny similarities Bond you
together facial
expressions body
language the way you
laugh or dress for an interview perhaps
when you hadn't a clue what your sister
was going to wear
go the synchrony in your lives
constantly confronts
[Music]
you when I see my sister I see myself if
she looks good I think I look pretty
today but she's not wearing makeup I say
my God I look
horrible it's hardly surprising because
you both come from the same egg you have
precisely the same
jeans and you're literally
clones better known as identical
twins but now imagine
this one day your twin your clone is
diagnosed with
cancer if you're the other twin what can
you do except wait for the symptoms
I have been told that I am a high risk
for
cancer HS over
me and yet it's not uncommon for a twin
like Anna Marie to get a dread disease
while the other like clotilde
doesn't but how can two people so alike
be so unalike
well these mice May hold a
clue their DNA is as identical as Anam
Marie and clotilde's despite the
differences in their color and
[Music]
size the human who studies them is Duke
University's Randy
jle So Randy I see here you have skinny
mice and fat mice what have you done in
this lab well these animals are actually
genetically identical the fat ones and
the skinny ones that's correct cuz these
are huge they're huge can we weigh them
to find out so if you take this is looks
like they can barely walk they they
can't walk too much they're not going to
be running very far so that's about 63 G
63 G let's look at the other
one so it's half the weight right this
gets even more mysterious when you
realize that these identical mice both
have a particular Gene called ay but in
the yellow Mouse it stays on all the
time causing
obesity just look at
this so what accounts for the thin Mouse
exercise
Atkins no a tiny chemical tag of carbon
and hydrogen called a methyl group has a
fixed to the AI Gene shutting it
down creatures possess millions of tags
like
these some like methyl groups attach to
genes directly inhibiting their
function other types grab the proteins
called histones around which genes coil
and tighten or loosen them to control
gene
expression distinct methylation and
histone patterns exist in every cell
constituting a sort of second
genome The epig
genome
epigenetics literally translates into
just meaning above the genome so if you
would think for example of the genome as
being like a computer the hardware of
the of of a computer The epig genome
would be like the software that tells
the computer when to work how to work
and how
much in fact it's the EP genome that
tells our cells what sort of cells they
should be skin Hair Heart
you see all these cells have the same
genes but their epigenomes silence the
unneeded ones to make cells different
from one another epigenetic instructions
pass on as cells divide but they're not
necessarily permanent researchers think
they can change especially during
critical periods like puberty or
pregnancy jles mice reveal how the
epigenome can be
altered to produce thin Brown mice
instead of fat yellow ones he feeds
pregnant mothers a diet rich in methyl
groups to form the tags that can turn
genes
[Music]
off and I think you can
see that we dramatically shifted the
coat color and we get many many more
Brown animals and that matters because
your coat color is a tracer it's it's an
indicator that's correct of the the fact
that you have turned off that Gene
that's
right this epigenetic fix was also
inherited by the next generation of mice
regardless of what their mothers
ate and when an environmental toxin was
added to the diet instead of nutrients
more yellow babies were born doomed to
grow fat and sick like their
mothers it seems to me this has profound
implications for our health it does for
human health if there are genes like
this in humans basically what you eat
can affect your future Generations so
you're not only what you eat potentially
what your mother ate and possibly even
what your grandparents ate so how do you
go to humans to do this experiment when
you have these mice and they're
genetically identical on purpose that's
right who is your perfect Lab
human well then we look for identical
humans which are identical twins
[Music]
twins and that brings us to the reason
why were showing you Spanish
twins in 2005 they participated in a
groundbreaking study in
Madrid its aim to show just how
identical epigenetically they are or
aren't one of the question of twins is
that if my twin has this disease I will
have the same disease and genetics tell
us that there is a high risk of
developing the same disease but it's not
really sure they're going to have it
because our genes are just part of the
story something has to regulate these
genes and part of the explanation is
epigenetics estellar wanted to see if
the twins epigenomes might account for
their
differences to find out he and his team
collected cells from 40 pairs of
identical twins Age 3 to
[Music]
74 then began the laborious process of
dissolving the cells until all that was
left were wispy strands of DNA the
master molecule that contains our
[Music]
genes next researchers Amplified
fragments of the DNA until the genes
themselves became
detectable those that had been turned
off epigenetically appear as dark pink
bands on the
gel now notice what happens when the
genes from a pair of twins are cut out
and
overlapped the results are far from
subtle especially when you compare the
epigenomes of two sets of twins that
differ in
[Music]
age here on the left is the overla DNA
of 6-year-old Javier and
Carlos the yellow indicates where their
gene expression is
identical on the right is the DNA of
66-year-old anamarie and
clotilde in contrast to the younger
twins hardly any yellow shines
through their epigenomes have changed
dramatically the study suggests that as
Twins age epigenetic differences
accumulate especially when their
Lifestyles
differ one of the main findings of our
research is that episomes can change in
function of what we eat of what we smoke
or what we drink and this is one of the
key uh difference between epigenetics
and
genetics as the chemical tags that
control our genes
change cells can become abnormal
triggering diseases like
cancer take a disorder like MDS cancer
of the blood and bone
marrow it's not a diagnosis you'd ever
want to hear
when I went in then he started patting
my hand and he was going your blood work
does not look very good at all and that
I had um MDS leukemia and uh that there
was not a cure for it and basically I
had 6 months uh to live Char
coar was epigenetics the reason could
the silencing of critical genes turn
normal cells into cancerous
ones it's scary to think that a few
misplaced tags can kill
you but it's also good news because
we've traditionally viewed cancer as a
disease stemming solely from broken
genes and it's a lot harder to fix
damaged genes than to rearrange
epigenetic
tags in fact we already have a few drugs
that will
work recently Sandra Shelby and Roy
kwell participated in one of the first
clinical trials using epigenetic
therapy the idea of epigenetic therapy
is to stay away from killing the cell
rather what we are trying to do is
diplomacy trying to change the
instructions of the cancer cells
reminding the cell hey you're a human
cell you shouldn't be behaving this way
and we try to do that by reactivating
genes the results have been incredible
and I didn't have really any horrible
side
effects I am in
remission and going in the plus
direction is a whole lot better than the
minus
Direction in fact half the patients in
the trial are now in
[Music]
remission but while it may be easier to
fix our epigenome than our
genome messing it up is easier
too we've got to get people thinking
more about what they do they have a
responsibility for their epig genome
their genome they inherit but their epig
genome they potentially can alter and
particularly that of their children and
that brings in responsibility but it
also brings in hope you're not
necessarily stuck with this you can
alter this
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