Can acquired traits and aptitudes be inherited through epigenetics ?

[Maciamo]

The idea may have sounded ridiculous to many scientists not so long ago. After all, when are born our brain is supposedly a blank slate. DNA only constitutes the body's building blocks, and the principles of Darwinian evolution states that any new mutation arises fortuitously. In contrast, Lamarck believed that an organism could pass on characteristics that it acquired during its lifetime to its offspring. The famous example that Lamarck gave was that "if giraffes stretch their necks to reach high leaves, their offspring have longer necks."

Even though the Lamarckian model of evolution was discredited as soon as it was proposed by the French scientists in the 18th century, the concept may make a come back thanks to new discoveries in the field of epigenetics. Two months ago, Brian G Dias & Kerry J Ressler published a paper in the journal Nature, in which they explain that mice whose father or grandfather learned to associate the smell of cherry blossom with an electric shock became more nervous than mice in the control group when exposed to the same odour, even though they never received the electric shock themselves. You can read about it in more details here.

If the study can be replicated with other stimuli and other animal it would mean that acquired fears, and by extension also memories, behaviours or even abilities can be inherited. This can be explained by the activation or deactivation of some genes through the process of DNA methylation and histone modification, which are the basis of epigenetic inheritance. Genes can be made more 'reactive' or 'sensitive' to stimuli, or conversely 'silenced' during an individual's life, due to a repeated exposure or behaviour, or due to a traumatic event. These changes are henceforth inherited by later generations, although they will weaken at each new generation and return to 'normal' after a few generations if the stimuli that caused the methylation are not repeated by the offspring.

There are been many human cases of apparently inherited fears or trauma, running in families for several generations, that were left unexplained by science. This could be for instance an irrational fear for the noise made by air raid sirens among children of young individuals (who hadn't had children yet) who experienced traumatic fears during air raids in WWII.

But if fears can be inherited through epigenetics, then it is reasonable to imagine that the (de)activation of certain genes could also have an impact on traits of character that were acquired through someone's early life. A more combative attitude can be acquired by children raised in a particularly competitive environment. We could even imagine that children trained to develop their memory would activate genes that increase neurotransmitters required for memory, and that their offspring would consequently benefit from an increased memory before they even start their own drill. The same could be true for physical abilities or even some forms of intelligence linked to more active genes of some kind.

It has been observed for a long time that some abilities run in families. Parents who are good at music tend to have children who are also good at music. Many lawyers have children who also become lawyers. It could be due to their childhood environment or to genetic predispositions towards some aptitudes. In the latter case it was almost always assumed that the increased abilities lied in the genetic code itself, in other words whether someone possessed or not a particular genetic variant or mutation, and that these were purely inherited by chance from one's numerous ancestors. But in some cases it may be that our parents or grandparents are the ones to thank for (or pity, in the case of trauma). Without their own personal experiences some of our genes would never have been (de)activated, and we would not have the same character or abilities.

Acquired trauma, such as PTSD, can have a devastating effect on someone's life. It is even worse if it is inherited by a person's children and grandchildren. Fortunately we ma soon have a way to remedy to that. The understanding of epigenetic mechanisms have already prompted researchers to develop drugs that can tweak epigenomes to get rid of these undesirable changes in our DNA.

[LeBrok]

I'm very sceptical about epigenetics being transferable to future generations. I will remain such till these studies can be duplicated beyond any doubt.
However I can see a process where some demethylation from stressed parent's DNA could be copied to offspring genome, causing some form of general nervousness in both.
I doubt that something more precise (precise knowledge) can be transferred this way.
It is inconceivable for me that a learned behaviour of parents could be written into DNA. It would mean that once brain is rewired (learn) and the change is positive (survive), the brain or other signaling medium would contact the right segment of DNA and change methylation only in this segment (out of millions of choices) in all cells, especially in new egg cells to be transferred to new generation.

It is also possible that frequent electric shocks could cause methylation problem. This could affect parent's sex cells and next generation being generally more nervous. The rest might be in the eye of scientists who want to validate their research a bit too hard.

[Maciamo]

I'm very sceptical about epigenetics being transferable to future generations. I will remain such till these studies can be duplicated beyond any doubt.
However I can see a process where some demethylation from stressed parent's DNA could be copied to offspring genome, causing some form of general nervousness in both.
I doubt that something more precise (precise knowledge) can be transferred this way.
It is inconceivable for me that a learned behaviour of parents could be written into DNA. It would mean that once brain is rewired (learn) and the change is positive (survive), the brain or other signaling medium would contact the right segment of DNA and change methylation only in this segment (out of millions of choices) in all cells, especially in new egg cells to be transferred to new generation.

It is also possible that frequent electric shocks could cause methylation problem. This could affect parent's sex cells and next generation being generally more nervous. The rest might be in the eye of scientists who want to validate their research a bit too hard.

Knowledge is a set of neural connections in the brain, not something that is set in the genes, and therefore isn't transferable to offspring. What I was referring to are genes that influence the way the brain works, or the "natural sensitivity" of a person for some things.

[Aberdeen]

I don't think there's anything surprising about the idea that the way we react to things could be encoded in our genes. It's been noted that many types of animals raised in a zoo environment seem to have an instinctive fear of specific types of predators that would have been a threat to them in the wild. Show a tame gazelle a hologram of a lion and the gazelle will freak out. And it's been shown that people will pick out a snake from the details in a shrub much faster than they will pick out any other details. That's apparently just as true for those of us who grew up in a part of the world where there are no poisonous snakes as it is for people living in countries like Australia where there are lots of poisonous snakes. It's just something that people became programmed to watch for in the past. And I suppose we could become wired to react to new warning signals, such as emergency sirens, and pass that on to our offspring.

[Maciamo]

I don't think there's anything surprising about the idea that the way we react to things could be encoded in our genes. It's been noted that many types of animals raised in a zoo environment seem to have an instinctive fear of specific types of predators that would have been a threat to them in the wild. Show a tame gazelle a hologram of a lion and the gazelle will freak out. And it's been shown that people will pick out a snake from the details in a shrub much faster than they will pick out any other details. That's apparently just as true for those of us who grew up in a part of the world where there are no poisonous snakes as it is for people living in countries like Australia where there are lots of poisonous snakes. It's just something that people became programmed to watch for in the past. And I suppose we could become wired to react to new warning signals, such as emergency sirens, and pass that on to our offspring.

Yes, we have known for a while that instinctive fears and many basic traits of characters (such as sociability or aggressiveness) are set in our genes. The big news here is that some of them could be modified in our DNA through life experiences and passed on to next generations ! The keyword in the title is acquired traits and aptitudes.

[Aberdeen]

Yes, we have known for a while that instinctive fears and many basic traits of characters (such as sociability or aggressiveness) are set in our genes. The big news here is that some of them could be modified in our DNA through life experiences and passed on to next generations ! The keyword in the title is acquired traits and aptitudes.

And that's exactly what I was talking about. If a gazelle that was raised in a zoo away from the lion cage is more afraid of a lion than it is of a hippo, some specific information about what type of large animals it should fear the most must have somehow become encoded in its DNA. And why do all people apparently have the instinctive ability to spot a snake more easily than other details that might be in their line of vision? I wish I could remember the source of that information, but I clearly remember reading about that in some science magazine. And, to me, it sounds like some kind of inherited learned behaviour. The question is how it happens and how long it takes for something like that to become part of one's genetic inheritance. If some people have inherited a fear of air raid sirens, it sounds as if that sort of thing can happen quite quickly, but I wonder how long it would take for that sort of fear to disappear from a genetic line if it's no longer useful.

[hope]

I have been fascinated by the study of epigenetics for several years. My interest spiked courtesy of the twin studies carried out by Tim Spector. From studying identical twins he shows how, even though they are genetically the same,
the environment can cause differences between them as time goes on.
Nurture acting on nature.

Regarding traits and behaviours,I think there is good epigenetic evidence from some animal studies, particularly in the last 5/6 years to show behaviours or traits can be carried across to the next generation and beyond.
Mice and rat research have shown a variety of inherited behaviours.

Studies on rat pups, who have been nursed and groomed well by mums, show these pups will in turn be good nurturing mothers to their own offspring. Whereas those who received poor nursing, in their turn made poor mothers.
Newborn rats, taken from mothers from day 1 -14, showed depressive like behaviours as adults and in turn their offspring also showed similar behaviour. http://www.ncbi.nlm.nih.gov/pubmed/2...ne&format=text
One study, in particular which had effects across several generations was that of Vinclozolin, the fungicide used to control rot or disease in fruit or vegetable crops. http://en.wikipedia.org/wiki/Vinclozolin
A study showed it impaired not only the fertility of rats exposed to it in utero but also those rats born over the next 2-3 generations or beyond.


Who knows what research will show, now it has taken off again in a serious way.

[Maciamo]

Here is another interesting article from Nature about the subject: Epigenetics: The sins of the father. With a little chart to illustrate the process.




A few excerpts.

Examples of epigenetic changes in humans and rats:

One study of Swedish historical records showed that men who had experienced famine before puberty were less likely to have grandsons with heart disease or diabetes than men who had plenty to eat⁵. Similar work with children in Britain reported in 2005 that fathers who had started smoking before the age of 11 had an increased risk of having boys of above average weight.
...
Male rats fed a high-fat diet, for example, beget daughters with abnormal DNA methylation in the pancreas⁷. Male mice fed a low-protein diet have offspring with altered liver expression of cholesterol genes³. And male mice with pre-diabetes have abnormal sperm methylation, and pass on an increased risk of diabetes to the next two generations.
...
Skinner's team exposed pregnant rats to large doses of pesticides and fungicides, which led to organ damage in their adult offspring. The sperm of male offspring showed changes in DNA methylation that persisted for at least four generations⁹.

How does epigenetic reprogramming work:

Some genes manage to escape these periods of major reprogramming. The best example is genes that are imprinted — whereby one copy from the mother or father is robustly methylated and effectively silenced. These silencing marks crop up in the egg or sperm and are retained in the embryo.
About 100 genes are known to be imprinted, but some non-imprinted genes may also escape the scrubbing through a similar mechanism. “There is a growing consensus that there are more regions than previously thought that escape reprogramming in sperm,” says Sarah Kimmins, an epigeneticist at McGill University in Montreal, Canada.
...
One route might be chemical marks on histones, the proteins around which DNA wraps. Acetyl and methyl groups can attach to histones and affect the expression of nearby DNA. But during sperm-cell formation, DNA is stripped of most of its histones (and their attendant marks) and wraps instead around protamines, which pack it more tightly.

Nevertheless, about 10% of human histones — and about 1% of mouse ones — are retained. These sites might carry information from one generation to the next. In 2011, researchers reported that, in nematode worms, certain histone marks correlate with long life and can be passed down through several generations¹³. And last December, Kimmins and her colleagues showed that feeding male mice a diet low in folate — a nutrient that provides the raw materials for methylation — led to significantly reduced methylation of histone proteins in the animals' sperm and more birth defects in their offspring¹⁴.

Still other studies point to a mechanism involving short RNA molecules latching on to DNA and affecting gene expression. Twenty-eight microRNAs are expressed differently in the sperm of men who do and do not smoke, according to a study reported in 2012 (ref. 15). And these RNA patterns may persist through multiple generations. Last year, Lane's group found that obese male mice show abnormal expression of 11 microRNAs in their sperm — and that they pass on insulin resistance to the next two generations¹⁶.

[LeBrok]

Nevertheless, about 10% of human histones — and about 1% of mouse ones — are retained. These sites might carry information from one generation to the next. In 2011, researchers reported that, in nematode worms, certain histone marks correlate with long life and can be passed down through several generations13. And last December, Kimmins and her colleagues showed that feeding male mice a diet low in folate — a nutrient that provides the raw materials for methylation — led to significantly reduced methylation of histone proteins in the animals' sperm and more birth defects in their offspring14.

Still other studies point to a mechanism involving short RNA molecules latching on to DNA and affecting gene expression. Twenty-eight microRNAs are expressed differently in the sperm of men who do and do not smoke, according to a study reported in 2012 (ref. 15). And these RNA patterns may persist through multiple generations. Last year, Lane's group found that obese male mice show abnormal expression of 11 microRNAs in their sperm — and that they pass on insulin resistance to the next two generations16.

Thanks Maciamo, this is great info in understanding epigenetics.

It clearly says that de-methylation, which is a damage to DNA expression system, is the main case of DNA changes inherited by next generation or two. It is basically a long lasting damage done to DNA.

It has nothing to do with transmission of adaptable traits, needed and beneficial behaviour.

In a sense it is actually the same as getting mutation on a gene, they are almost always bad or nutral, people get birth defects, get genetic diseases, die sooner, or there is no effect at all. Sometimes though mutation turns to be more beneficial than destructive for the organism, and as such is passed to next generations. Unlike genes, Methylation (epigenetic) changes are no stable, not permanent, and can't be passed further than one or two generations. It means they don't conform to evolutionary forcings. In this case 99.9999% of epigenetic changes are destructive or neutral for organizm.

Nevertheless, about 10% of human histones — and about 1% of mouse ones — are retained. These sites might carry information from one generation to the next.

That's a great info, exactly explains how methylation damage could be passed to next generation.

[LeBrok]

feeding male mice a diet low in folate — a nutrient that provides the raw materials for methylation — led to significantly reduced methylation of histone proteins in the animals' sperm and more birth defects in their offspring14.

Make sure your diet contains adequate amount of Vitamin B9, Folic Acid!

It is especially important in aiding rapid cell division and growth, such as in infancy and pregnancy.

DNA synthesis and repair are impaired and this could lead to cancer development.^[7]

Your body produces million of new cells every day to replace dead ones. Lack of methylation can cause DNA defects in new cells, meaning that you will not be as healthy as possible and die sooner.

Food to eat:

Folate naturally occurs in a wide variety of foods, including vegetables (particularly dark green leafy vegetables), fruits and fruit juices, nuts, beans, peas, dairy products, poultry and meat, eggs, seafood, grains, and some beers.^[9][69]Spinach, liver, yeast, asparagus, and Brussels sprouts are among the foods with the highest levels of folate

http://en.wikipedia.org/wiki/Folic_acid

[LeBrok]

It just occurred to me that many diseases can be caused by inadequate methylation. It is interesting how genetic statistics never will tell anyone that a person will get sick for sure, even if a person carries genetic predisposition for this disease. The best they can do is to issue approximate percentile for probability of sickens, like 32%. Likewise study with twins prove that in spite having identical (or almost) DNA one can get sick, with hereditary disease, but not the other. Surely, beside of genetic predispositions, there are environmental factor like diet, radiation, air quality, way of life, etc. These factors always affect creation of new cells and their DNA in our body. And it happens that every day thousands of our cells are dying and thousands of new ones take their places. Likewise thousands of new DNA strands are copied. To achieve exact copy, not only all the letters need to fall in proper places but also methyl groups need to be present and used in right places to keep some genes dormant, inactive. In well functional cell only the needed genes are expressed, the rest are sleeping, winded tight around methyl groups.
Some inherited from parents genes carry predispositions to certain diseases, to which a person have a chance to succumb. If these bad genes are always wrapped around methyl group, then nothing bad is going to happen. However in time of inadequate supply of methyl groups, due to environmental factors, these genes will be expose to protein production, other words they will become active. Let's say with age and constant production of new cells, and long period of methyl group shortage, a person might receive millions upon millions of new cells with exposed bad genes. It might be ok for some time, but when certain threshold is crossed a disease will start acting up.
Unfortunately I can't point to which diseases can start this way, nor I haven't find a research telling us so. I just had a thought. :)

Does it make some sense?

[Angela]

It makes sense to me, but I don't have any scientific evidence to support it. This is way outside my areas of even hobbyist expertise. :)

I only have anecdotal evidence to contribute. I know that physicians don't really understand the inflammatory disease process that causes things like the various auto-immune disorders. They do believe there is a genetic component, but they also believe that environmental stressors are needed to activate these diseases, among which are repeated infections, emotional stress, and even physical stress, as in accidents, serious bone injury etc.

The same is true with things like colon cancer. Siblings can both carry the problematic mutation, or lack the protective mutation, but one succombs and the other doesn't.

I'm not sure how this would tie in.

[Theodorik]

It has been proven that traits can be passed on for several generations through epigenetics. For example, Swedes whose grandfathers had experienced hunger, were more likely to be obese. The science is settled on this. I would post links, but I'm not allowed as a new member.

[Mary]

I am sangeetha,born on nov 23 1985 in chennai,india at 10:50 am...i just want to know whether i can plan to conceive now,i am also a person with bipolar disorder,when will i be peaceful?