La epigenética se erige como una de las disciplinas más fascinantes y revolucionarias de la biología moderna. En su esencia, la epigenética estudia cómo factores ambientales, como la dieta, la contaminación y el estrés, pueden modificar la expresión de nuestros genes sin alterar la secuencia del ADN. Este campo de investigación revela por qué, a pesar de compartir el mismo material genético, los gemelos pueden tener diferencias marcadas en sus características físicas y de salud.
Además, la epigenética nos permite entender fenómenos como la diferenciación de las abejas, donde una abeja se convierte en reina o trabajadora en función de las condiciones en las que se desarrolla. Las marcas epigenéticas no solo afectan a los individuos, sino que también pueden ser heredadas por las futuras generaciones, lo que implica que nuestros estilos de vida pueden influir en la salud y el bienestar de nuestros hijos y nietos.
Esta revolución epigenética desafía las viejas creencias sobre la genética, sugiriendo que la biología no es un destino inmutable, sino un proceso dinámico que puede ser influenciado por nuestras elecciones y el entorno. A medida que profundizamos en la epigenética, abrimos la puerta a nuevas posibilidades en medicina, nutrición y salud pública, con el potencial de transformar nuestra comprensión de la herencia y la enfermedad.
**Hashtags:** #Epigenética, #BiologíaModerna, #SaludYBienestar
**Keywords:** epigenética, expresión génica, factores ambientales, dieta, contaminación, estrés, herencia epigenética, gemelos, diferenciación celular, revolución biológica.
Además, la epigenética nos permite entender fenómenos como la diferenciación de las abejas, donde una abeja se convierte en reina o trabajadora en función de las condiciones en las que se desarrolla. Las marcas epigenéticas no solo afectan a los individuos, sino que también pueden ser heredadas por las futuras generaciones, lo que implica que nuestros estilos de vida pueden influir en la salud y el bienestar de nuestros hijos y nietos.
Esta revolución epigenética desafía las viejas creencias sobre la genética, sugiriendo que la biología no es un destino inmutable, sino un proceso dinámico que puede ser influenciado por nuestras elecciones y el entorno. A medida que profundizamos en la epigenética, abrimos la puerta a nuevas posibilidades en medicina, nutrición y salud pública, con el potencial de transformar nuestra comprensión de la herencia y la enfermedad.
**Hashtags:** #Epigenética, #BiologíaModerna, #SaludYBienestar
**Keywords:** epigenética, expresión génica, factores ambientales, dieta, contaminación, estrés, herencia epigenética, gemelos, diferenciación celular, revolución biológica.
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TVTranscripción
00:00The hands, the eyes, the face, our body is a swarm of billions of cells that treasure
00:12the DNA that our parents have passed on to us and that our children inherit.
00:18What exactly is transmitted from one generation to another, from one cell to another?
00:23We know that DNA is transmitted, but it is not the only thing.
00:30Monozygotic twins or identical twins have the same genome.
00:34So, why are they not always the same?
00:39The genome is like a book that can be read in very different ways.
00:44For a long time, scientists have believed that DNA controlled our biological destiny.
00:52But things are not that simple.
00:56The advancement of technology and its new tools allow us to affirm that, in the study
01:01of DNA, we must consider the impact of the environment.
01:07Biologists from all over the world are investigating this new mystery.
01:11Exploration is to search in all cells, to know new knowledge and to go where people
01:16have not been before.
01:18It is a scientific adventure that will allow us to discover the hidden factors that alter
01:22our DNA, our identity and perhaps our genetic heritage.
01:37The human being has always been fascinated by the laborious bee.
01:44Its nature never ceases to raise questions to scientists who, little by little, are unraveling
01:49the mysteries of its development.
01:56There are thousands of species.
01:59Perhaps the best known is the domestic bee or the honeybee.
02:05A colony like the one I have in front of me is made up of a large number of workers
02:10that can range between 20,000, 30,000 and even 40,000 and a single queen bee that is
02:17the mother of all the others.
02:20The queen of this colony is easily distinguishable because they have placed a red dot on her back
02:25to always know where she is.
02:28Her body is different from that of her daughters.
02:30Its silhouette is longer and has a slightly wider thorax.
02:36The queen is the only fertile bee, the only one that can mate and her mission in life
02:41is to lay eggs.
02:55The queen is very different from the workers that pollinate around her.
02:59However, in its earliest stage, all the larvae are identical.
03:03What is the mechanism that turns one of them into a queen?
03:16The mystery was not unraveled until the middle of the 20th century.
03:26The process that makes a larva become a queen instead of a worker is based on the
03:31food that it receives.
03:34Larvae eat royal jelly for three days.
03:37Then, if they are destined to become workers, their diet varies.
03:42Royal jelly is mixed with larval papilla, made up of pollen and honey.
03:48Instead, the future queen will continue to be fed royal jelly during the rest of her
03:53larval stage.
03:57What shows that a simple nutritional change can make a significant difference between
04:02two similar beings during the first days of their life.
04:07But how is it possible that an external element can have such an impact on their development?
04:13Isn't that supposed to be controlled by DNA?
04:19To understand this process, it is necessary to go back to the origins of one of the most
04:24fascinating aspects of biology.
04:27The sequencing of the human genome.
04:34Scientists spent a long time trying to understand the way in which the characters of one generation
04:40to another are transmitted.
04:41And finally, in 1952, the exclusive role of DNA was completely ratified.
04:51The nucleus of each human cell contains 23 pairs of chromosomes.
04:57Each chromosome is made up of two chains of DNA.
05:04It has four nitrogenous bases, represented by the letters A, T, G and C.
05:10The DNA of a human being has 3 billion letters that are assembled to form the genes, which
05:16in turn synthesize the proteins, the basic parts of living beings.
05:22The sequencing of the human genome, which exposes the detailed map of our 25,000 genes, ended
05:28in the year 2000, which opened the door to immense possibilities.
05:40This is today's headline.
05:42Today, we feel happy to unveil the first draft of the great book of human life.
05:57Scientific journals published the map of the all-powerful genome.
06:01Its almost complete sequencing aroused the most incredible hopes, such as the discovery
06:06of the genes of obesity and schizophrenia and the eradication of cancer.
06:11The promises of science seemed to have no end.
06:17It is very likely that scientists are largely to blame for so much talk about the importance
06:23of DNA.
06:24They proclaimed that we had decrypted the human genome.
06:28Deciphering is taking a encrypted message and making its reading intelligible.
06:32But reading the translation does not imply understanding its meaning.
06:36It was then that we started decoding, which will still take us some time.
06:46Scientists know that this adventure has just begun and that the text they have in their
06:52hands is very difficult to interpret.
06:56We cannot answer all the questions by looking only at the DNA sequence.
07:03We need to know the whole genome.
07:06Our biological complexity does not respond only to the characteristics of the DNA.
07:10It also depends on how it is used, read and transmitted.
07:17A few months after the sequencing of the human genome, Science magazine first dedicated
07:23an entire issue to epigenetics, the study of the factors that interact with the genes
07:28and its possible hereditary transmission.
07:33The unanswered questions began to accumulate.
07:43Scientists were looking for new elements to explain the beauty and complexity of the
07:48human being.
07:49In Australia, a research laboratory is trying to better understand the laborious bee, sequencing
08:00all its genome.
08:03The results show that there is no genetic difference between the larvae of the queen
08:08and the workers.
08:10They all share the same DNA.
08:23If the difference is not genetic, it may be epigenetic.
08:28Everything seems to ratify that the royal jalea is capable of creating an interaction
08:32with the initial genes of the larva and convert these into genes of the queen.
08:39The process begins during the larval state.
08:42After three days, the future queen receives an exclusive feeding.
08:46A change that will profoundly modify its development.
08:51After the metamorphosis, the nymphs progress at a different pace.
08:56The development of the queens is much faster than that of the workers.
09:01A queen will be ready to emerge in just two weeks, but the workers will need
09:06one more week.
09:10So it is the royal jalea that makes the difference.
09:13But how does it work on the genes of the larva?
09:21The methylation of DNA, an epigenetic mechanism, is what triggers these different
09:26development programs.
09:30The DNA of the bee contains about 10,000 genes.
09:33And as in all living organisms, some of its genes are expressed in scientific language,
09:39while others remain inactive.
09:43The expression of the genes can be silenced by the methylation of the DNA, a kind of
09:49chemical mark that is added to a gene and allows to turn it off, as if it were a switch.
09:54If the methylation of the DNA is intense in the initial stages, we will have worker bees.
10:03But if we suppress the methylation, we will have queens.
10:07In the same way that feeding activates an epigenetic program that determines the creation
10:12of workers or queens, we inject into these eggs some molecules that interrupt the methylation
10:18of the DNA, which will allow them all to become queens.
10:26The system used to create a queen is surprising and shows that certain chemical modifications
10:32in identical genes can play a crucial role in the development of a living being.
10:38The unique case of bees could be reproduced in other species?
10:43Jonathan Weitzman has his own opinion on this.
10:48I will give you an example.
10:50I am British and this is my queen.
10:53She was born a queen, so we could say that she is a genetic queen.
10:58On the right you can see the queen of bees, but the queen was not in her genes.
11:03Over time, a larva becomes a queen because it is fed with royal jelly.
11:09As you can see, in England there are two ways to become a queen.
11:13You can be the genetic queen, and in some cases, not very often, you can become a queen
11:19by interacting with the real environment.
11:25What are we made of? Who are we?
11:28Whether it is scientists or cells, DNA does not explain our immense diversity.
11:34The cells of the liver, the eye or the hand have the same genome.
11:40However, they are almost as different as scientists.
11:43How is it possible to be so complex?
11:48Jonathan Weitzman is passionate about this topic.
11:51He keeps asking questions about the behavior of our cells.
11:57In our body there are hundreds of types of cells
12:00with very different behaviors and characteristics
12:03that will transmit to the next generation of cells.
12:07The cells of the liver, the neurons, the lymphocytes in the blood, the skin cells,
12:13all of them behave differently and use the genome in a very different way.
12:19And yet, they all come from the same original source, the fertilized egg.
12:25And I wonder, how can this original cell give rise to such a diversity of cellular states
12:31starting from the same genome?
12:33The Scottish biologist Conrad Waddington,
12:36the first to use the term epigenetic,
12:39began to answer this question in the 1940s.
12:44Waddington kept asking himself how a embryo could become
12:48a being composed of varied and numerous cells
12:51from a single cell.
12:54Conrad Waddington drew a landscape with a mountain,
12:58and at the top he placed several cells
13:01represented by balls of the same color
13:04that, as they descended through their irregular slopes,
13:08could become different cells depending on the path they took.
13:14So, at the top, when they start to slide from the summit,
13:17their course is uncertain.
13:19At that moment, they can become different cells,
13:22and as the cell moves down that path,
13:25it becomes more and more narrow,
13:28depending on which valley it goes into,
13:31and that position will be shaped.
13:39Cells of the liver, of the heart, of the skin, of the brain,
13:44the destiny and the identity of our cells
13:47is not only engraved in the DNA.
13:50Other mechanisms work so that the cells
13:53differentiate and store the memory of their identity.
13:58We are all aware that the origin was an egg,
14:02and from there, each living being was perfecting
14:05an epigenetic mechanism to read genetic information.
14:09There is something magical about all this.
14:12I find it wonderful to think that we are beginning
14:15to understand how it works,
14:19that we are understanding how a small plant
14:22can be created from genetic information
14:25that has been modified for 2 billion years,
14:29and that we are learning to read the coding system
14:32that has made that plant, or the human being that I have in front of me.
14:37The genome does not change during cell differentiation,
14:40what changes is the way to use it,
14:43and it is the epigenetic mechanisms that determine
14:46which part is used and which part is not.
14:52The way our genes are expressed
14:55is decisive for the development of our cells.
14:59There are many ways to explain what epigenetics consists of.
15:03The metaphor that works best is music.
15:06Musical scores have lines and characters
15:09that set the guidelines for playing the music.
15:16But every time those signs are interpreted
15:19by different artists, they sound different.
15:26In this metaphor, the score is the DNA.
15:29But for the melody to sound,
15:32we need musicians,
15:35and for the melody to sound,
15:38we need musicians,
15:41and for the melody to sound,
15:44we need musicians and an interpretation.
16:03The same genetic score
16:06can be interpreted in different ways.
16:10Monophygotic twins are the perfect example.
16:14They come from the same ovum and share the same DNA.
16:19But their genome seems to have been interpreted by different musicians.
16:24I love garlic.
16:25I hate it.
16:26He runs much faster than me.
16:28He needs training.
16:30My French is not bad.
16:32I don't even speak it.
16:37Jonathan Weitzman and his twin brother, Matthew,
16:40are researchers.
16:42They share the same DNA
16:44and the same concerns about identity.
16:47Maybe we're interested in genetics
16:49because we've always been fascinated
16:51by hereditary transmission,
16:53what makes us who we are.
16:55We're a combination of our genome,
16:57of our epigenome,
16:59and of our experiences.
17:01That's what makes me who I am today.
17:03But those new experiences
17:05and the changes in my epigenome
17:07will make me who I am tomorrow.
17:12The genome is relatively static.
17:14The epigenome, in comparison,
17:16is relatively dynamic.
17:18Identity, who we are,
17:20changes over time in our life.
17:22And so the epigenome,
17:24in a certain way,
17:26acts as the carrier
17:28of the memory of our past
17:30and contributes to define
17:32what we are at every moment.
17:34So the longer we live,
17:36the more our epigenomes diverge.
17:38And there was something
17:41that was identified
17:43by recent investigations.
17:51Throughout life,
17:53genes interact with many factors.
17:55Our experiences
17:57condition their expression.
17:59But how does that influence
18:01two monocygotic twins
18:03that share the same DNA?
18:05This is what researcher
18:07Manel Esteller is trying to find out
18:09Manel Esteller
18:11How are you?
18:13Fine. Hello.
18:15Berta?
18:17Yes. Grisela.
18:19Welcome.
18:21As you know, we are studying epigenetics.
18:23Alterations or changes
18:25that you can have
18:27in your genetic material
18:29despite being twins.
18:31They are normal changes.
18:33There is nothing to worry about.
18:35I can explain some differences
18:37You are now more equal
18:39or more different than 10 years ago.
18:41Do you differ little
18:43or are you still very close?
18:45Physically, I think
18:47we are differentiating a little.
18:49The features are changing.
18:51Yes.
18:53Monocygotic twins
18:55can also be different
18:57if you look at the fingerprints.
18:59Do you see them different?
19:01This is a purely epigenetic change
19:03without any genetic alteration
19:06They are very similar
19:08but they can be distinguished.
19:10There are certain differences.
19:12This is the appearance
19:14at birth.
19:16I was born with this stain
19:18and she did not.
19:20What is this change due to?
19:22We do not know.
19:24It could be that there was
19:26a small genetic mutation
19:28or it could be an epigenetic change
19:30associated with it.
19:32We will not know until we look at it in detail.
19:34You are genetically identical
19:36but epigenetically you are diverging.
19:38You are diverging
19:40because lifestyles are different.
19:42You can see it physically
19:44and also in the growth
19:46that you will have
19:48and also in the diseases.
19:50This will change
19:52and it will be very important
19:54for these two individuals
19:56who are not photocopies.
19:58The conclusions derived
20:00from the study of twins
20:02and diseases
20:04but it is not a closed book.
20:06These studies were key
20:08to demonstrate
20:10that there is genetic determinism
20:12but not 100%.
20:14Studies with identical twins
20:16allow us to evaluate
20:18the influence of epigenetics
20:20on development.
20:22But does it also intervene
20:24in the appearance of diseases?
20:27The study of monocytotic twins
20:29is also important in cancer
20:31because we sometimes have
20:33the question of people
20:35who have a dominant mutation
20:37that considers a risk
20:39of 80-90% of breast cancer
20:41and one of the sisters
20:43has breast cancer at 60
20:45and the other does not
20:47or has it at 90.
20:49How is it possible
20:51if her DNA is the same?
20:53Because there are epigenetic differences
20:55between identical twins
20:57that could reveal anomalies
20:59and even serve as markers
21:01to control the appearance
21:03of diseases as serious
21:05as cancer.
21:17The research team
21:19led by Edith Heard
21:21of the Coogee Institute
21:23has brought new hopes
21:25in this field.
21:27We already knew
21:29that cancer is a genetic disease
21:31and that some changes
21:33in the DNA play
21:35a relevant role
21:37in its appearance.
21:39But our research shows
21:41that it is also
21:43an epigenetic disease
21:45and reaffirms our conviction
21:47that changes in the expression
21:49of genes,
21:52as well as in the expression
21:54of genes,
21:56can be caused
21:58by a mutation
22:00in the DNA.
22:02This is the case
22:04of the X chromosome.
22:06The X chromosome
22:08represents
22:10a mutation
22:12in the DNA
22:14of the X chromosome
22:16and the X chromosome
22:18of the Y chromosome
22:20The females have
22:22two X chromosomes
22:24and the males one X
22:26and another Y.
22:28The Y only has 100 genes
22:30compared to the 1,300
22:32that the X treasures.
22:34So, to balance the balance,
22:36one of the female chromosomes
22:38is inactivated at the beginning
22:40of embryonic development.
22:42An epigenetic mechanism
22:44known as genetic dose compensation
22:46that helps keep one of the X chromosomes
22:48inactivated throughout the life
22:50of the female.
22:52The inactivation
22:54of the X chromosome
22:56is essential.
22:58If one of them
23:00is not inactivated
23:02during the development
23:04of the female,
23:06the embryo will die immediately.
23:08The genetic balance
23:10is essential.
23:12An excess of expression
23:14of the X chromosome genes
23:17including felines
23:19and human beings
23:21is essential.
23:27This vital phenomenon
23:29provides a lot of information
23:31about the functioning
23:33of healthy cells
23:35and cancerous cells.
23:37As a general rule,
23:39our cells double
23:41their DNA
23:43and are divided into two equal cells
23:45The X chromosome
23:47is inactivated
23:49during the development
23:51of the female.
23:53But what happens
23:55when a cell
23:57loses this memory?
23:59Researcher Ronan Salignet
24:01is an expert
24:03in this field.
24:05In normal state,
24:07the inactive X chromosome
24:09occupies a small part
24:11of the cell nucleus.
24:14In tumor cells
24:16there is a change
24:18in the silent state
24:20of the inactive X chromosome.
24:22It has a more relaxed
24:24and much denser structure.
24:26In cancerous cells
24:28with altered epigenetic mechanisms,
24:30in the inactive X chromosome
24:32the reactivation
24:34of some genes
24:36that are normally off occurs.
24:38It seems to be shown
24:40that the reactivation
24:42is a discovery
24:44that opens new paths
24:46in the scientific crusade
24:48against cancer.
24:50Epigenetics is a branch
24:52of very promising biology
24:54in the fight against cancer
24:56because epigenetic modifications
24:58are reversible.
25:00Correcting a genetic mutation
25:02is very complicated.
25:04But epigenetic alterations
25:06can be reprogrammed
25:08with certain molecules.
25:10There is great hope
25:12that some cancers
25:14can be treated with drugs
25:16designed to influence
25:18the epigenetic machinery.
25:20Some epigenetic drugs
25:22are already in the test phase.
25:24But researchers have discovered
25:26that certain drugs
25:28that have been in the market for years
25:30already act on the epigenetic mechanisms.
25:36A drug used for decades
25:39has turned out to be an epigenetic drug.
25:41We are talking about decitabine,
25:43indicated in the treatment
25:45of myelodysplastic syndrome,
25:47a blood disease
25:49that can lead to leukemia.
25:51Years ago, it was found
25:53that this drug slowed
25:55the progression of the disease.
25:57It is an example of an epigenetic drug
25:59successfully used.
26:01However, it is important to emphasize
26:03that we have not yet fully understood
26:05the epigenetic mechanism
26:07of these drugs.
26:09We know that some have shown
26:11their effectiveness.
26:13The challenge now is to understand
26:15how they act.
26:17Epigenetic drugs are opening
26:19new paths in the fight
26:21against cancer.
26:23The influence of epigenetics
26:25on the development of the body
26:27and in some diseases
26:29is increasingly palpable.
26:33But if genes are transmitted
26:35from one generation to another,
26:37could not the mechanisms
26:39that alter the expression
26:41of these genes also be transmitted?
26:57The type of information
26:59transmitted to the next generation
27:01remains an open issue.
27:04We know that genes
27:06transmit physical features.
27:08I look like my father and my mother
27:10and my son and my daughter
27:12look like me.
27:14But what else do we inherit?
27:16We have researched DNA a lot.
27:18Mainly because with today's technology
27:20it is quite easy to examine
27:22a DNA sequence.
27:24So now what interests us most
27:26is to know what is transmitted
27:28along with that DNA,
27:30what travels with it.
27:34Understanding the elements
27:36of this transmission
27:38is a difficult task
27:40in which plants can help us.
27:44Geneticist Van San Colo
27:46carries out his research
27:48in a species of the same family
27:50as the mustard plant,
27:52the Thaliana arabidopsis.
28:00Arabidopsis is a very interesting plant
28:02for a geneticist
28:04because it is very prolific
28:06and because it has a very short
28:08development time.
28:10Its life cycle in the laboratory
28:12can be completed in two months
28:14and also has a very compact genome.
28:18Can Arabidopsis transmit
28:20visible changes
28:22to its offspring,
28:24such as roots of different lengths
28:26or a more or less early flowering
28:28without altering its DNA?
28:30To find out
28:32the researchers made
28:34epigenetic modifications
28:36in a plant of this species.
28:40Then they made a cross
28:42with a wild specimen
28:44and after a series of successive crosses
28:46they examined the following generations
28:48carefully.
28:53The analysis showed
28:55that the epigenetic modifications
28:57were transmitted
29:00to at least 16 generations.
29:06These modifications were associated
29:08with visible changes
29:10such as the length of the roots
29:12or the flowering period.
29:14For the first time,
29:16some scientists had proof
29:18that some characteristics
29:20can be transmitted
29:22to a large number of generations
29:24without altering the DNA sequence.
29:26We have found
29:28that the epigenetic variations
29:30transmitted through generations
29:32have less stability
29:34than the changes transmitted
29:36by the DNA sequences.
29:38These very long phrases
29:40composed by the letters A, P, C and D
29:42are transmitted with extreme fidelity.
29:46But we have proven
29:48that the epigenetic states
29:50are much less stable.
29:52Its transmission will last
29:55tens or even hundreds
29:57but not millions of generations.
30:08This experiment has shown
30:10that it is possible
30:12to transmit certain epigenetic marks
30:14that modify some aspects of the plant.
30:17In this case,
30:19the modifications were induced
30:21in the laboratory in a controlled way.
30:23But what happens in nature?
30:29Could some changes
30:31be induced by the environment?
30:33For example, by a drought?
30:36It is a great mystery.
30:38The environment influences
30:40the functioning of genes
30:42but we still do not know
30:44how far hereditary changes
30:46that affect several generations
30:48can dictate.
30:50Does the environment play a role?
30:53To try to find the answer
30:55to this question,
30:57Van Sankolo and his team
30:59have installed hundreds of plants
31:01genetically identical
31:03in the mechanical bands
31:05of a unique device in the world,
31:07the X-ray.
31:16Thanks to this mechanical rotation system,
31:18all plants receive the same light,
31:20which allows them
31:22to measure the impact
31:24of the different irrigation intensities.
31:30These are the questions
31:32that concern us.
31:34What are the conditions
31:36that cause the appearance
31:38of epigenetic variations?
31:40Is the environment capable
31:42of inducing this type of change?
31:44And if so,
31:46will the changes we observe
31:48be as stable as those
31:51of the previous generation?
31:53And until when?
31:55These are the unknowns
31:57that we try to clear
31:59thanks to this unique system
32:01called the X-ray.
32:09The results of this research
32:11will allow us to elucidate
32:13whether some environmental factors
32:15such as drought
32:17can influence the plant genome
32:19and how the environment
32:21affects the rest of the species.
32:23What do we know
32:25about its impact
32:27on our own genome?
32:29There are many open investigations
32:31to try to know
32:33exactly what type of information
32:35is inherited
32:37in addition to the genetics.
32:39Does the environment
32:41in which we live
32:43affect the data
32:45we transmit?
32:47Some researchers think
32:49that its influence is very subtle,
32:51but others are convinced
32:53that its impact is considerable.
33:12In the American Northwest,
33:14a researcher is convinced
33:17that the environment
33:19plays a crucial role
33:21in the functioning
33:23of our body
33:25and that it leaves
33:27lasting and transmissible
33:29traces through
33:31epigenetic mechanisms.
33:33This specialist in biology
33:35of reproduction
33:37came to epigenetics
33:39almost by accident.
33:41A manipulation error
33:43allowed him to study
33:45what is known
33:47as serendipity,
33:49an unexpected discovery,
33:51a kind of stroke of luck.
33:53We wanted to study
33:55the effects of a fungicide
33:57on gestating rats,
33:59evaluate the way
34:01it affected the fetuses
34:03exposed
34:05and analyze
34:07the consequences
34:09that the offspring
34:11would have
34:13on the male rats.
34:15A small dose
34:17of these substances
34:19was inoculated
34:21in females in gestation.
34:23The offspring looked normal,
34:25but when they reached adulthood,
34:27the males presented
34:29anomalies in the sperm
34:31that caused a decrease
34:33in fertility.
34:35In the next generation,
34:37in the grandchildren
34:39of the inoculated females,
34:42and then
34:44the surprise jumped.
34:46The youngest males presented
34:48the same anomalies
34:50without having been exposed
34:52to pesticides,
34:54neither by injection
34:56nor in the uterus.
34:58In addition,
35:00in each generation
35:02epigenetic modifications
35:04related to sperm anomalies
35:06were discovered.
35:0890% of the males
35:10in this generation
35:12did not follow
35:14the canons of classic genetics,
35:16so we continue to investigate
35:18to show that the epigenetic factors
35:20can be transmitted
35:22for several generations.
35:24No laboratory has carried out
35:26a similar study
35:28or obtained the same results.
35:34But Skinner assures
35:36that pesticides can create
35:38non-genetic and yet
35:40transmissible diseases.
35:44For some,
35:46it is a very limited work
35:48with hasty conclusions
35:50that only incite controversy.
35:52If what you do
35:54does not arouse controversy,
35:56it is not important.
35:58With subtle changes
36:00that do not alter the accepted concepts,
36:02you will never make a great progress
36:04in the field of science.
36:07If all scientists
36:09worked with an open mind,
36:11as I try to do,
36:13many dogmas would be questioned
36:15considered immovable.
36:17But the usual tendency
36:19is to accept the dogmas
36:21and work with them
36:23without daring to change them.
36:25For me that is not
36:27the best way to do science.
36:29Michael Skinner's concern
36:31is shared today
36:33by many laboratories.
36:35We have used mice
36:37to test the hypothesis
36:39that exposure to an episode
36:41of traumatic stress
36:43during childhood
36:45can permanently alter
36:47epigenetic mechanisms
36:49and modify behavior
36:51during adulthood.
37:05The offspring are separated
37:07from the mother suddenly
37:09and on repeated occasions.
37:17We have found that exposure
37:19to periods of chronic stress
37:21alters the behavior of the mouse
37:23and modifies a certain
37:25number of epigenetic mechanisms
37:27in the brain.
37:29And what is most important,
37:31these alterations are transmitted
37:34to the second generation
37:36and also to the third.
37:38Adults who suffered
37:40these episodes of stress
37:42during childhood
37:44are depressive,
37:46evaluate the danger worse
37:48and take more risks.
37:50Their mental disorder
37:52will be transmitted
37:54to their children
37:56and even to their grandchildren.
37:58What this experiment shows
38:00is that not everything
38:02but the mental disorders
38:04and childhood traumas
38:06are very important factors
38:08that can determine
38:10our behavior
38:12during several generations.
38:18The most exciting thing
38:20about epigenetics
38:22are the benefits
38:24that its knowledge
38:26can report to the human being.
38:28There are many psychiatric diseases
38:30whose causes are not known
38:34and deepening
38:36the epigenetic mechanisms
38:38could allow us
38:40to better understand
38:42these diseases.
38:44It is still too early
38:46to say that the epigenetics
38:48of men and mice
38:50is comparable.
38:53But the work
38:55of Mansu
38:57and Skinner
38:59seems to suggest
39:01that the genome
39:03would be almost defenseless
39:05against the attacks
39:07of its environment
39:09and that it would leave
39:11transmissible marks
39:13for several generations.
39:17Conclusions
39:19that cause controversy
39:21in the scientific community.
39:23If we were so sensitive
39:25to the epigenetic changes
39:27induced by the environment,
39:29it would be a real mess.
39:31The cells would change identity,
39:33we would have a lot of tumors,
39:35we would not even be alive.
39:37To what extent
39:39are we permeable
39:41to the environment?
39:43And what do we transmit
39:45to our children?
39:47The influence
39:49of epigenetics
39:51collides
39:53with limits
39:55that have just been discovered.
39:57After fertilization,
39:59the epigenetics
40:01of mice
40:03and chickens
40:06are erased
40:08by the epigenetic marks
40:10provided by the sexual cells
40:12, allowing
40:14a kind of
40:16new generation.
40:22However,
40:24cleaning is not total.
40:26Some marks remain.
40:28But which and why?
40:30Wolf Reich and his team
40:32work in Cambridge
40:34to solve this mystery.
40:38It is very likely
40:40that epigenetic transmission
40:42between generations
40:44is related to the fact
40:46that the erasure of the marks
40:48is never complete.
40:50We would like to understand
40:52what is the mechanism
40:54that decides which part
40:56of the information is erased
40:58and which part is not.
41:00We would also like to find out
41:02if there is a resource
41:04that we can activate
41:06that allows us
41:08to choose between erasing
41:10the information
41:12or transmitting it
41:14to future generations.
41:16It is a very exciting question.
41:18Selective erasure
41:20is very well appreciated
41:22when observing groups
41:24of very early embryonic cells
41:26in the microscope .
41:28The nuclei, in blue,
41:31the few marks transmitted
41:33by the parents
41:35that have not been erased
41:37appear in violet color.
41:39But a few days later,
41:41the embryonic cells,
41:43already in a more advanced state,
41:45contain a constellation
41:47of new epigenetic marks
41:49linked to their development.
41:51We have been studying thoroughly
41:53the erasure process for 10 years
41:55and I find it more and more fascinating.
41:57There are still many questions
41:59to be answered.
42:01For example,
42:03we consider it very likely
42:05that food affects the epigenome
42:07and that it is affected
42:09by what we eat,
42:11by the situation
42:13and climate of the place
42:15where we grew up
42:17and by the environment
42:19in which we are immersed
42:21and also by the penalties
42:23that our parents had to face
42:25and by the composition
42:28of the food.
42:30A team of researchers
42:32tries to clarify
42:34if food is able
42:36to mark the DNA
42:38and if the affected DNA
42:40can be transmitted
42:42to the next generations.
42:54Anne Ferguson Smith
42:56What is the impact
42:58of food deprivation
43:00on pregnant mice,
43:02on their young
43:04and on their copious offspring?
43:06The malnutrition of the mother
43:08during pregnancy
43:10has important effects
43:12on the young.
43:14Pregnant females
43:16of our experiment
43:18receive half
43:20of the usual caloric dose,
43:22a fairly severe nutritional cut.
43:24They become fat
43:26and diabetic.
43:28They do not normally assimilate
43:30glucose or insulin,
43:32which causes them to suffer
43:34diseases very similar
43:36to those that the human being
43:38suffers in today's society.
43:40Their fat content increases
43:42and obesity and diabetes
43:44make their appearance.
43:46However, if after birth
43:48we continue to feed
43:50these little mice,
43:53the mice exposed
43:55to food deprivation
43:57in the mother's womb
43:59seem to adapt
44:01to the caloric shortage.
44:03And so,
44:05when they grow up
44:07in an environment
44:09where food is abundant,
44:11they are easy prey
44:13for diabetes and obesity.
44:15The grandchildren of the mothers
44:17who started the experiment
44:19have the same symptoms.
44:21How many generations
44:23could be affected
44:25by these diseases?
44:27Research with mice continues.
44:33But,
44:35in our case,
44:37will feeding influence
44:39in the same way?
44:41We cannot carry out
44:43this type of experiment with humans,
44:45but throughout history
44:47there have been times
44:49when pregnant women
44:51have had to face similar
44:53situations and penalties
44:55as happened during the Dutch famine
44:57of World War II.
44:59During the winter
45:01of 1944-1945,
45:03the Nazis blocked
45:05the supply of food
45:07to the population of the Netherlands
45:09as punishment for their support
45:11to the Allies.
45:13An atrocious episode
45:15that has provided valuable data
45:18These moving images
45:20show the hard tests
45:22that pregnant women
45:24had to live
45:26during that period of deprivation.
45:28The health of their children
45:30has been the subject
45:32of a thorough study.
45:34And the results show
45:36that they are more likely
45:38to suffer diseases
45:40such as diabetes and obesity,
45:42to suffer neurological disorders
45:44such as depression and schizophrenia
45:46The follow-up of the grandchildren
45:48has shown that they,
45:50in adulthood,
45:52also suffer an obesity
45:54higher than average,
45:56which shows that the conditions
45:58of the environment
46:00affect at least two generations.
46:02Research on the impact
46:04of the environment
46:06on the genome
46:08has only just begun.
46:10There are still many mysteries
46:12to be solved.
46:14It is the most important
46:16and powerful transmission mechanism,
46:18which allows to transfer
46:20the characteristics of an individual
46:22to its descendants.
46:24But today we know that there is something else,
46:26something that has a great impact
46:28on health and well-being
46:30and that can be inherited
46:32by the next generation.
46:34I am passionate about trying to understand
46:36how these non-genetic mechanisms work,
46:38whose effects can be prolonged
46:40for several generations.
46:44What fascinates me most
46:46about epigenetics is that
46:48it provides many nuances
46:50to interpret a genome
46:52that we considered static.
46:54It allows us to examine
46:56the marks left by the environment,
46:58those marks chiseled
47:00in the course of each personal history
47:02in the behavior of the genome.
47:04And what I like most
47:06is that its effects are reversible.
47:08It is comforting to think
47:10that there is nothing immovable.
47:13It is a science
47:15that expands the field of genetics.
47:17Not everything is transmitted
47:19in an immutable way.
47:21In the information that is inherited,
47:23there are many transitory data
47:25that accompany those recorded in stone.
47:27Well, epigenetics occupies
47:29a large part of that
47:31that is not recorded in marble.
47:33Research on epigenetics
47:35is in full swing.
47:39But it will take many more years
47:41to interpret all the tones
47:43of such a prolific score.