Memory is inherited? WTF? Epigenetics...

[TheFallen]

Okay. I've often wondered about the mechanics of instinctual fear, but have always presumed that it was a learned behaviour.

Now there's a credible scientific study that apparently demonstrates beyond reasonable doubt that an unnatural Pavlovian fear induced in mice is passed down via at least the paternal line to at least the next two generations...

WHUT???

The smell of fear can be inherited, scientists prove.

Study shows scents associated with terror may be passed on for two male generations.

Scientists have shown for the first time that fear can be transmitted from a father to his offspring through his sperm alone in a ground-breaking study into a new kind of genetic inheritance.

Experiments on mice have demonstrated that they can be trained to associate a particular kind of smell to a fearful memory and that this fear can be passed down through subsequent generations via chemical changes to a father’s sperm cells.

The findings raise questions over whether a similar kind of inheritance occurs in humans, for example whether men exposed to the psychological trauma of a foreign war zone can pass on this fearful behavioural experience in their sperm to their children and grandchildren conceived at home.

The researchers emphasised that their carefully controlled study was carried out on laboratory mice and there are still many unanswered questions, but they do not discount the possibility that something similar may also be possible in people.

The full article can be found here. It's well worth a read.

This field of research is apparently called "epigenetics" and it's completely boggled my mind... induced memories can be inherited??? Parental experiences potentially directly affect offspring???

Don't forget that this has apparently been demonstrated at the highly respectable Emory School of Medicine in Atlanta, Georgia in a "higher species", namely a mammal... we're not talking liver flukes or fruit flies here. The researchers have no idea what the transmission method is - it's certainly not via DNA, because needless to say the frightened mice's DNA wasn't altered in any way - as far as current scientific understanding goes, anyway. They suspect a bequeathable chemical change in the father mouse's sperm. Whatever the transmission method is, it certainly tends to shoot a few holes in current Mendelian/Darwinian theories of heredity, apparently showing them to tell only part of the story, whatever that story is.

If proven true, this brings up literally MASSIVE amounts of all sorts of ethical questions. Maybe the sins of the fathers are truly visited upon their sons?

[Hashi Lebwohl]

If proven true, this brings up literally MASSIVE amounts of all sorts of ethical questions. Maybe the sins of the fathers are truly visited upon their sons?

I disagree--there aren't any ethical questions involved even if this sort of transference is proven via independent testing. Yes, the actions of the parents can sometimes have repercussions for the children but the children never, under any circumstances, bear any responsibility for the choices their parents make.

I must admit this would be a fascinating discovery, if proven true.

[TheFallen]

We don't disagree, Hashi. Okay my "sins of the father" quote was confusing. Rather than assigning any form of culpability to offspring, I was in fact mulling over the possibility of actions performed by said offspring being less their fault than previously believed - so, exculpability rather than the reverse. And yes, of course I acknowledge that people are capable of making choices as to how to behave, but still...

I've explained that very badly - but if negative emotion is in some way hereditary, it becomes more problematic to assign guilt in certain circumstances. Hell, I can't think of a good example, but I'm sure you know what I'm getting at.

[Hashi Lebwohl]

Yes, your clarification makes perfect sense.

[Vraith]

I've been waiting for SOME mechanism like this [though not exactly this, by any means] to be found.
Partly because of what is shown...but mostly cuz of what ISN'T [actually COULDN't be] shown...in the research on child abuse and bullying that I saw as part of my Education education in psych/development classes.

It will be interesting to see how this works out in the end...but I can imagine a fairly simple [heh...simple in description, not in execution] process.

How many sperm do men produce? I think it's many millions a day. The production of every one of those wigglers MUST be influenced by what's going on in the man's body AT THAT INSTANT. We already know this as fact.
Stress [heh...everything in life] has chemical effects. The effects affect the production process.

They should look at the offspring and see if SOME of them are actually LESS afraid/immune to certain stimuli...because I suspect this will end up being far less specific/particular and far more potentializing/structural preference.

[And, BTW, also probably true of women...recent studies seem to show that the old "truth" that women are born with all the eggs they'll ever produce is probably not true...it is MORE true of men, cuz the production rate is much faster...cuz the shelf life is much shorter. A woman at 30 has most of the same eggs she had at 20...a man at 30 probably doesn't have any sperm he had 20 DAYS ago.]

[TheFallen]

You're right to highlight the unlikeliness of the specific, V. That's what I found most startling because - if the study is to be believed - the implication at least was that the first and second generation mice offspring were only susceptible to the triggering scents. They weren't apparently more generally fearful of any unknown scent.

Sure, I get that, because of the continuous nature of sperm production within the body (and that being a natural biochemical process), it's more than possible that such sperm could be changed chemically dependant upon the level of stress within the potential father at the time. However, a specific chemical change within the sperm that creates an inbred fear only of certain very specific scents? That's staggering, if true.

I'm presuming that the scientists tested offspring mice to see if they reacted fearfully to other unknown scents and found that they didn't. What would also have been interesting would have been to test offspring of a conditioned mouse father, where such offspring had been conceived say two months after the last paternal conditioning, to see if such information-carrying change was still present in the father's sperm after such an intervening period.

If this does turn out to be proven, then it has wide implications and almost gives some (slight) credibility back to the thoroughly debunked evolutionary theories of Lamarck. Consider for example the hypothetical child of a soldier suffering from PTSD after battle? Or possibly even the hypothetical child of a father with an ingrained hatred of the police? Or does the same thing occur with preference as well as aversion? Is it also about -philia as well as -phobia? If so, then how about the hypothetical child of a paedophile? Or rapist? Or murderer? Yes of course, free will still comes into things entirely, but despite that, if the above is true, what does it do to our views on nature versus nurture? Or our notions of culpability? Does it make things just a little more fuzzy?

The whole thing is both fascinating, remarkable and just plain weird.

[Vraith]

It is weird and fun.
I can't think of a good reason that attraction would be excluded, and only
aversions passed on...though the negative might be more common because in general it seems that sudden chemical spikes from fear-events happen more often to most people than shocks of ecstacy.
I suspect, even if it happens in people, it will probably be less potent...just because one aspect of moving up the evolutionary ladder is fewer and less powerful instincts. Dogs have fewer automatic reactions and more choices than mice, dolphins fewer and more still, humans the least and most [so far].

The PTSD thing is a good question...and, to expand it a bit:
Will the inheritor be born with PTSD? Or will it be only a potential that is meaningless unless it is triggered? Will the trigger have to be something very similar to the parent's? [Like exposure to gunfire, or a roadside bomb]
Or more general? [exposure to unexpected loud sounds, having a high-stress job working in tightly bonded group]
And I still want to know: if someone faces extreme circumstances and overcomes the fear/trauma, is that resilience/capacity/adaptive response passed/passable?

[Avatar]

Interesting questions.

--A