This is such an odd preoccupation of places like the guardian and has a lot of the hallmarks of the discredited recovered memory movement/therapy[1][2]. There's never any discussion of epigentic changes that effect somatic cells vs gametes, or even of the competing definitions of epigenetic changes.
Here's a quote from the article:
> Scientists working in the emerging field of epigenetics have discovered the mechanism that allows lived experience and acquired knowledge to be passed on within one generation
This is obviously such a nonsense interpretation of epigenetic changes that it's hard to take anything in the article seriously.
Obviously there's real science happening around epigenetics and there are interesting findings, reporting like this is a really big leap.
I read the article, the linked study, and two studies citing the linked study. The claim that memories or “lived experience” is inherited is not supported by the study.
Erm…memories — by any biologically reasonable definition— are separate from epigenetic changes. No serious researcher would conflate the two, other than perhaps hippy-dippy ‘biologists’ who struggled through ‘Physics for Poets’, as undergrads. Source: Biophysicist for 30 years now.
Further, even if the study had held up, there is a vast difference between memories retained through an individual metamorphosis event, and passing memories along to offspring resulting from sexual reproduction. The OP fails to recognize this obvious point.
No, I said, “There is a vast difference between memories retained through an individual metamorphosis event, and passing memories along to offspring resulting from sexual reproduction. The OP fails to recognize this obvious point.”
You’re selectively quoting and then re-arranging the quotes to attempt to make yourself look better.
Honestly, for someone to be posting this nonsense with a link to their LinkedIn professional profile in their bio is kind of career suicide. You’ve inadvertently stumbled into an argument on a IT tech website with people who are bona fide life scientists and are embarrassed and are clumsily trying to save face.
My career is doing just fine, actually. Like, better than ever and I'm not making this up.
Feel free to add me on LinkedIn, I have no issue in people knowing who I am; should I be scared or anything? Lol. You should try not being anonymous, just a suggestion, :).
You said:
"Memory [...] is separate from epigenetic changes"
I replied with a study that seems to suggest otherwise. That's not really hard to follow ...
>IT tech website
Hmm naw man, Hacker News is way more than that. Also, why would I be embarrassed? You are just projecting too much unto others, chill.
>and has in fact shown that larvae do not carry over memories through metamorphosis
Nope.
The 2008 study is "the first to demonstrate conclusively that associative memory survives metamorphosis in Lepidoptera".
The article you cited does not disprove this, but rather it shows the brain structure of (some, at least) insects get completely re-arranged before/after their transition to adulthood.
For me, this only makes the 2008 study more interesting, since the memories could still persist, even after a completely new brain architecture (!).
That 2008 study has never been reproduced and the piece in Quanta points towards it being impossible. Our current understanding of memory is that it has a physical basis, so that 2008 study is likely wrong.
Appealing to authority is one of the most primitive logical fallacies out there.
But if we're going to do that, let's do it properly and choose the peer reviewed article written by experts in the field over a blog post written by a "science communicator".
Ha. You tried to appeal to authority by insinuating you’re a professional biologist. First, you’re not. You appear to be primarily an app developer, not a researcher. Which is why I mocked you by pulling my 30 years on you.
I definitely would not call myself a "professional biologist" as that would make a whole room burst with laughs, lol. So, you're right on that.
But I do work as a researcher, publish some interesting papers from time to time and, yes, I think I'm also an "app developer", in the sense that I've made some apps?
These kind of arguments you make really come across as quite infantile, to be honest. I'm going to have to stop engaging with you because no substantial value is added to the conversation while you already crossed the line to personal attacks, several times, even after you've been told about it and pointed to this site's rules. Find somebody else to engage with your tantrums, I'm out.
You serve up a distasteful dish of arrogance and ignorance. You drop into a conversation implying you’re a professional biologist (“Source: biologist for 20 year”) when you’re not - that’s the arrogance. You then make wildly inaccurate statements any real life scientist knows isn’t true for cheap internet points from software folks who don’t know any better- that’s the ignorance. You finish it off with a dollop of childishness on top by complaining when actual scientists call you out on your nonsense. Do better. I know you can.
Again the 2008 study has never been reproduced to my knowledge and defies everything we know about how memory is stored, so I think skepticism of such an incredible claim is warranted.
I'm not commenting on whether you're right or wrong about biology, obviously—I have no idea. But it's not ok to violate HN's rules like this, regardless of how right you are or feel you are. I appreciate that you've been a biophysicist for 30 years and we certainly want that people with that depth of expertise on HN, but even more important is that you not put down or ridicule others.
I know that in the history of science and academia there has at times been a culture of hard-nosed ridicule of others who are deemed to be wrong and/or not knowledgeable enough to enter a discussion. Perhaps that approach is still vital in some professional circles, maybe? I don't know, but I can tell you for sure that on an open internet forum like HN, such an approach just poisons everything it touches.
Incidentally, if you do happen to be right, that makes it even worse to post these sorts of attacks, because then you end up giving people a reason to discredit you which has nothing to do with the truth. Lots of past explanation about this if anyone cares: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor....
You've broken the site guidelines since then too, so this is unfortunately a pattern:
Eh, I mean what other explaination is there for "instinct". You have genetic and epigenetic factors that give something a predisposition to respond to stimuli in a specific way. Makes sense to me, but it's just a theory (as most things are) and we have a lot more to learn.
There’s a big difference between DNA methylation on gametes leading to behavioral predispositions in offspring and the claim that memories and experiences are inherited.
It depends on what you mean by memories. I'm not a fan of the Guardian as I've seen stuff editorialized to the point it conveys misinformation. This article is poorly written to the point the writer doesn't seem to understand the topic.
"Epigenetic memories" is different than colloquial "memories". The article seems to completely miss this. And of course people who haven't been exposed to that domain specific concept are likely to misinterpret it.
It's intentionally misleading given that "memory" has a common understanding. If they simply wanted to keep the article approachable, they could even just simply write "they're analogous to memories, but don't work like memory as most people understand it."
Memory is the wrong word to use even like that. To the extent that there is DNA methylation in gametes, it will up or down regulate the expression of existing genes in the DNA. Nothing is created de-novo as in memory, you can’t look at the resultant gene regulation and look backwards to a cause.
Then please go tell all the publications and researcher that they are wrong for using the term "Epigenetic memory" in thier domain. Or are you a domain expert (in the minority if you are)?
The study[1] mentioned in the guardian does not contain the phrase "epigenetic memory", and only contains the word memory twice, and both uses are of the conventional definition. The author in the guardian is misrepresenting the science.
I agree that the article is garage. The point of contention is around epigenetic memory being a thing or not. It is a common term used in the domain, such as in this paper and others.
You could probably replace the word memory in that paper with maguffin and not change the meaning. It's totally unconnected to the common definition or the use in neurology. I guess what I'm getting at is that this kind of reporting obscures what's going on intentionally for the political aims of the guardian. Which I think is lousy.
I'm not a domain expert in epigenetics, but in grad school for bioinformatics I did a bunch of research on nucleosome positioning[0] which is epigenetics-adjacent.
"Epigenetic memory" is the term of art I was taught in grad school. Either they've changed that in the last 10 years, or ch4s3 is attempting to assert a different definition of "memory" than the one used in the field.
They are also incorrect. DNA methylation is an actual methyl group chemically binding to an actual DNA nucleotide, and staying there. When we flip a bit on a hard drive platter we call that "memory" as well.
Well, you've got brain wiring that causes you to respond to stimuli in a certain way. A small portion of that wiring is genetic (e.g. opposite sex attraction, fear of heights, disgust at certain smells), and the rest comes from prior sensory exposure (i.e. is learnt during your own lifetime).
Is there a good, real-world example of how we think epigenetics works? I've seen a lot of mentions that "epigenetics _proves_ that intergenerational trauma is real!" -- and at least to my eyes this feels like a stretch of the science. For instance, why are epigenetic effects inherited? Why is it not the case that in environment, the parents experience one environment and so some genes are expressed. (ie, epigenetics happens based on that environment) and then the children are in the a different environment, and so different genes are expressed.
Do I have a wholly-incorrect understanding of epigenetics? Is there a clear and simple example of an epigenetic mechanism?
It seems pretty clear for example that being an alcoholic can cause DNA methylation in your gametes such that your offspring have a higher risk above and beyond regular genetic factors to become an alcoholic. However that is at a population level and there are complicating factors.
Inherited trauma is totally unsupported but up or down regulated gene expression based on environmental factors before your conception are supported by some compelling evidence.
I'm trying on a mental model re: Epigenetics. How does this look:
Your genes are a recipe book, not a blueprint. What recipe is chosen is based somewhat on environmental effects. When you reproduce, you shuffle together the parents book + the earmarks on the pages.
This is only true if you take a pretty narrow definition of the word "trauma".
One example would be an ancestor experiencing famine, who then passes down epigenetic markers have marked effects on their offspring in terms of health, longevity, and behavior.
The Dutch Hunger cohort study is highly suspect. However, the idea that someone is literally starving to death just before or during gestation having some knock on genetic effects is not all that surprising. But again, the phrase "inherited trauma", as it's typically used is bunk.
Also the phrase "a heritable memory" is kind of nonsense even with respect to epigenetic changes. Again what we're talking about with epigenetics is up or down regulation of your existing genes, not some new information being encoded.
I found the research about the Chinese Suihua cohort to be more compelling.
I fully agree that someone starving to death right around the time of pregnancy could have some knock on effects; this is discussing changes in the following generation, the ones that are tens of years removed from the starvation event.
> Also the phrase "a heritable memory" is kind of nonsense even with respect to epigenetic changes. Again what we're talking about with epigenetics is up or down regulation of your existing genes, not some new information being encoded.
I wonder if you are missing the forest for the trees here somewhat. We're talking about the up/down regulation of specific genes based on specific methylation patterns in DNA that are present only because of some event that occurred. It's not memory in the sense of "I remember what I had for breakfast this morning", but it's memory in the sense of "these methylation patterns exist because their genesis was triggered by a specific event in the last few generations". That IS new information being encoded, just in a more fuzzy way than with neurons or computer memory.
I would need more convincing to think the phrases you mention are nonsense/bunk. Could you perhaps articulate the definitions you're using for "trauma" and "memory"? I think we are using different definitions, as it seems clear what is meant by the phrases as used.
EDIT: what issue do you take with the Dutch hunger study? I hadn't heard criticism about it before, and I just googled "dutch hunger cohort study criticism" and found nothing.
>just googled "dutch hunger cohort study criticism" and found nothing
x2
@ch4s3 is making some pretty strong claims here and there, for which I do not see the evidence either.
Don't take me wrong, I don't mean to suggest he's just being a quack; but rather, this is an invitation for him to substantiate his knowledge. The more we learn the better, :).
So check this study out[1] it uses the Dutch hunger winter families cohort day as a starting point, but uses a web based form to follow up on obesity. This is obviously not going to yield great results. And the findings show that only the adult children of famine exposed fathers are more likely to be obese which seems a little add. It has nearly 600 citations.
My criticism is that a lot of studies based on the data to lazy things like this, draw big conclusions, and get a lot of citations but there just isn’t much to them.
I've never read the Chinese Suihua cohort study so I'm not going to speculate or comment on it.
I think "in the last few generations" is a little speculative. There's strong evidence for epigenetic changes being passed from parents, but going further back the evidence is much weaker.
> what issue do you take with the Dutch hunger study
It's a really narrow study of a rather genetically homogeneous group picked from a really small geographic area and it has all of the issues of any retrospective study. The outcome could just be random chance. If you look at any small closely related group you're just going to find some sort of weird clustering, even if it varies in that group. If similar epigenetic markers showed up in other populations with similar well documented circumstances it would be stronger.
The basic idea is that genome modifications can be inherited with the genome. Methylation is one example; histone mods are another. If you want specific examples, I'd recommend focusing on a specific type of modification and searching "fill-in-the-blank inheritance", to avoid the more dramatic pop science.
I'm in a comp bio PhD studying epigenetics in development and disease. Epigenetics can be thought of as the set of biochemical mechanisms other than the linear sequence of DNA that store and respond to information to control cell behavior. This is how normal development from a single zygote to an adult organism is controlled, why cells vary so much despite having (mutations/mosaicism aside) the same DNA, how cells respond to changing biochemical conditions, and where cancer comes from.
The classic example of epigenetics - of stable information transfer between cell generations not based on DNA sequence - is methylation of cytosines. Here's the simplified version. As you know, the DNA is based on ACTG. When you have a CG, the C can be methylated, which means an extra carbon is attached at a specific position on the molecule. That extra carbon gets 'copied' when the DNA is duplicated during mitosis and gets passed to the daughter cells. Yet it can be added or erased during the cell's lifetime. It typically works to block proteins responsible for transcribing genes into mRNA from binding to the gene, so the gene is silenced when it is methylated. This gives a way to transmit patterns of gene expression across generations of cells.
This mark is extremely well-studied and understanding everything about DNA methylation is beyond this humble PhD student. But there are also extremely mechanisms for erasing and/or resetting certain aspects of cell state during mitosis or meiosis, including RNA, the proteome, and methylation state. We can't take it for granted that just because there's a mechanism by which biochemical information could be transmitted that it actually is (or that it isn't).
A common source for the idea of intergenerational trauma being supported by epigenetic evidence is the Dutch hunger winter [1]. The idea is that an experience that parents had in utero seems to have had an effect on the physical development of their children, in a way that's specific to parental sex. I'm willing to say "sure, that effect could be real and there could be an epigenetic explanation." But AFAIK we don't know specifically what that hypothetical mechanism would have been.
Note that the bod(y|ies) of the mother and child are interchanging material and engaging in biochemical crosstalk constantly during gestation, so there is abundant opportunity for environmental influences on the mother to have lifelong impacts on the child. Since the child's body will in turn engage in the same 'dialog' with the child's own children during fertilization and gestation, it's entirely possible for environmental influences on generation 1 to impact generation 3 as mediated by generation 2 via an in utero exposure.
All that said, I have a lot of uncertainty about what our priors ought to be on how important such hypothetical mechanisms might be. I think that in the coming decades, we'll make huge progress in understanding development and disease within an individual's body through an epigenetic lens. We will probably also see some interesting controlled experiments on "epigenetic inheritance" using short-lived model organisms, such as fruit flies or worms. Possibly we will collect enough epigenetic information in large-scale biobanks over 20-40 years that we can get a more detailed understanding of possible epigenetic inheritance mechanisms in humans, but these assays are currently quite expensive, and moreover there's no single measure applicable to an individual person, since the whole point of epigenetics is that the state varies across cell and tissue type.
The cohort studies around the Dutch Hunger Winter are really interesting but it’s a huge leap to generalize from maternal starvation during gestation have all kinds of effects to some fanciful ideas of inherited trauma writ large.
Yeah but so many people want to believe this idea. Consider all the history of people of "royal blood" as if that endeared them with the knowledge and skills of ruling. There is a whole industry that plays to this desire of people to "know". From palmistry to genetic memory, they are all bonkers.
I can not look into my genes so I know nothing about that, but what I can say with confidence is that trauma therapy continues to fundamentally change how I judge, act and react, and has deeply positive effects on all my relationships. I can totally see how that positively influences how my children will develop. That aspect of “passing on trauma“ is very real. I now stay calm and regulated in most stressful situations, and in the few cases where I overreact I know how to and I have the ability to (!) make up for it later and correct my mistakes. And use the trigger to further heal past pain.
Definitely. People want to believe it so badly that they'll just throw all logic out the window. I can't find it with a cursory search, but I recall one case in which a person allegedly inherited a fear of drowning via "genetic memory" from her uncle who drowned shortly before she was born. It's essentially "psychic medium" bullshit with a veneer of pseudobiology. But hoo boy, does that ever play well.
It's one thing to suggest that psychological or metabolic stress could affect the dynamics of DNA methylation in a way that crosses generational boundaries. It's quite another to identify those inherited dynamics as "memories".
Why yes, this stuff jumps diagonally. That's called an epigenic memory cross-transfer. It also works backwards and if one of the being is dead, and affects you from your birth even if the event had not happened yet at the time. Retcon Epigenetics 101.
It's easy to mistake upbringing with something inherited, or culture and behaviour with familial / race / appearance. I'm sure THAT part is partially inherited (same with the pattern recognition mentioned above).
I always wonder how animals that aren't raised by parents know various things...like why do predators know bright colors are a 'warning' if they don't have parents to teach them? How do spiders know what their web 'should' look like (spider webs come in multiple styles...)
People say 'instinct' by never mention what that means or how it works :-P
There's an idea of 'fixed action patterns' where certain behaviors are encoded in the neurology of an animal, and triggered by certain stimulus.
For spiders then there is an action pattern that upon certain stimulus they will use their spinnerets begin forming a web, first placing anchor points and gradually building it up with radial threads and spiral. The exact behavior differs by species such that they have different resulting patterns. It seems possible that there is an element of 'learning' beyond the basic pattern as well, even in seemingly very simple animals.
I doubt the spiders have a mental model of what their web looks like as such, it's more evolutionary driven genetic behavior, a particular neuronal pattern encoding the action sequence rather than an underlying fundamental understanding.
>For spiders then there is an action pattern that upon certain stimulus they will use their spinnerets begin forming a web, first placing anchor points and gradually building it up with radial threads and spiral.
I can sorta understand stimulus causing them to start making a web (sorta like stimulating a mammary can cause lactation) - but how do it 'know' to use a radial pattern rather then ah-hoc mess the black widows on my porch make? The 'ad-hoc' pattern seems like it would be more 'likely' then a nice pattern? Overall, I guess it just seems like a rather complex pattern/behavior?
Also, I guess I have a more basic question of 'what is instinct' if its not some sort of 'memory'? People seem to have an 'instinct' of the mechanics of throwing a ball, yet we have wildly different abilities with regards to accuracy, 'form', distance/speed (due to muscalture?) - it just seems like we have an 'instinct' for the 'simple' mechanical movements but not for the more complex behavior like throwing a ball to hit a target ?
The stimulus starts the fixed action pattern, but that action pattern includes the behavior to make the entire web, not just the start off the process. Different species of spider have different fixed action patterns (and different neurology underlying that, and different DNA underlying that neurology).
I think throwing a ball is more learned, although some behaviors like grasping the ball may provided a fixed action foundation on which higher order learning builds. Baby humans have a grasp reflex that works in a similar way to the fixed action pattern described, but with a simpler action sequence. If you touch the palm of a toddler, they will instinctively tightly grasp. It's interesting that the grasp reflex disappears around 5 years old, so the fixed neuronal pattern is subsumed by higher order learned behavior.
>>includes the behavior to make the entire web, not just the start off the process.
Thats where I get stuck..the 'behavior' has to account for different sizes of webs (the spider might be in a tight space, or a more open space), etc.
That just seems like an incredibly complex behavior to encode...Cells are supposedly 'simple' organisms but they manage to create/manage such complex behaviors...it's mind blowing..
> I can sorta understand stimulus causing them to start making a web (sorta like stimulating a mammary can cause lactation) - but how do it 'know' to use a radial pattern rather then ah-hoc mess the black widows on my porch make? The 'ad-hoc' pattern seems like it would be more 'likely' then a nice pattern? Overall, I guess it just seems like a rather complex pattern/behavior?
My guess: It "just feels right".
In the beginning (?), the species didn't have any "preference" and just did whatever. Some species cut the pizza in circles (as in, cutting out a circle from inside the pizza, leaving a donut-shaped pizza), others cut squares, others cut weird shapes, etc. All over the place.
Over time, those predisposed to cutting the pizza in a straight line, from border to border, passing through the center, began to survive slightly longer than the rest (for some unknown reason), becoming the dominant predisposition. To anyone born since then, it just felt right to cut the pizza that way. Not passing through the center of the pizza was just weird. And stopping a cut midway, without going all the way through, was also just weird.
At that point the amount of cuts still varied though, so it was all over the place. Some cut it in half, other made 2 cuts (4 slices) but they were in ugly 20° angles (so 2 huge slices and 2 small slices), others made hundreds of cuts so each piece was tiny and was annoying to eat, stuff like that.
Over time, those who preferred to cut the pizza in 90° angles started to survive slightly longer, and over time became the dominant predisposition.
And so on and so on. With these learnings it was becoming easier for people to make pizza ("find food"). Pizza sizes increased, and so did the amount of people sharing a single pizza. Making it easier to attract others, and share a pizza with them. Meeting more people makes it slightly more likely to find a life partner.
Time passed, same old song and dance. Now all pieces must be symmetrical. It was the most fair way to share. Not doing it this way meant the one doing the cuts was evil and must be avoided.
Current situation: Most people cut the pizza in 8 equal-ish slices because it just feels right to do it that way. Those who don't do it that way might still reproduce, but are slightly more likely to be avoided because they are weirdos. They are also slightly less able to get food, because nobody wants to share their pizza with those weirdos, so they are slightly more likely to starve due to being unable to "attract" food.
In that parallel universe, someone named 224hcem asks:
> But how do they "know" to cut the pizza in 8 equal slices rather than the ad-hoc mess the teenagers next door make with their microwaved pizza? Overall it's way more effort to try to make all pieces nice and equal, and the movements have to be more precise meaning the brain calculations are more complex compared to just winging it.
You can basically think of insects like this as organic ASICs. Input in, output out. It's a biological circuit that just has a raw response that's hardcoded in. Kind of like asking how does a computer know to do "MOV". It's baked in to the circuit. Do trial and error trillions of times and some of the circuits end up functioning and survive.
I'm pretty sure it's generally 1 spider per web, and I thought blackwidows (assuming they are still alive) take down the webs when done. So presumably you have quite a few spiders.
I've always wondered why so many different culture know some notion of a dragon. Is it possible that these are based on inherited memories, patterns, insticts of dinosaurs? I know this would be a wild leap but one my wonder.
The trick is that "some notion of a dragon" is incredibly vague, with "dragons" sharing very few commonalities between cultures. A European wyvern and Quetzalcoatl are almost nothing alike, yet people consider them both "dragons."
>Is it possible that these are based on inherited memories, patterns, insticts of dinosaurs?
It is possible that these are based, at least in part, on the discovery of dinosaur fossils, but humans didn't even evolve until the dinosaurs were long dead. So even if it were possible for "inherited memory" to include visual memories it wouldn't do so for dinosaurs.
It isn't a matter of "species boundaries," which aren't even really rigidly defined, so much as time, complexity and information compression.
It doesn't seem likely that whatever primitive mammalian ancestor eventually evolved into primates, and then into humans, carried within it a coherent enough visual and behavioral memory of dinosaurs to have survived so many generations of mutation, eventually informing the modern idea of "dragons" as winged reptiles.
And again, it isn't even true that there is a cross-cultural concept of "dragons" to begin with. It's a eurocentric myth, in that it assumes a Western concept of a "dragon" to be the default, and ignores any other cultural context in order to fit their mythologies into that mold.
Sidenote: My brother the biologist tells me that cats do not instinctively understand that heights can be dangerous; they have to learn it by trial & error.
To be fair, animals who don't try to avoid drowning, are more likely to drown before being able to reproduce. Probably even by trying to drink water or wash their face, since both mouth and nose usually lead to lungs (I bet there exists some weird animal where that's not the case).
Also, humans don't instinctively understand that fire can be dangerous, so there's that.
I didn't realize people don't have an instinct about fire. I always thought kids touching hot stoves/fire was because their hands touched it before their brains registered 'hot! ouch!'
Most DNA is non-coding and encodes tweaks to which genes are expressed where and how. The same way evolution evolved reliable formation of complex body arrangements out of stochastic molecular processes and variations in gene expression based on location, nearby cells and their own signalling, it's done the same for neurons which are far from a homogenous mixture and thus can learn some things("instinctual behaviour") easier than others, all the way to it happening essentially automatically.
I'm amazed by how cells know what to grow 'into' as well - especially since stem cells seem to be able to grow into just about any body part?
>>and thus can learn some things("instinctual behaviour") easier than others
I don't understand this - Isn't 'instinctual behaviour' something you don't have to learn? Also, I wonder if there's a limit to how complex a behavior can be 'encoded'? like bright colored animals == poisonous. That requires being able to tell a say a toad from a bird, what a color is, what colors = poison, etc? That seems like a pretty complex behavior...Do we have any idea what the limit is for complex behaviors in genes?
To be clear, I'm not an expert, but the way I imagine it is as genetically encoded biases to process information differently based on its colour, position, which neuron(s) or receptors it's coming in from, etc. that don't necessarily encode the entire neural circuitry for a behavior, but make it automatically learnable without the need for full-blown experiences, just as a consequence of the neurons developing and being exposed to normal environmental information at all.
I guess I just get floored that such complex behaviors can be encoded. Like how some people seem to 'just know' how to draw and I can't draw a straight line with a ruler...
> I'm amazed by how cells know what to grow 'into' as well - especially since stem cells seem to be able to grow into just about any body part?
AFAIK the current explanations for this often involve electrical and chemical gradients, along with "timer" cyclic reactions among groups of cells.
A contrived example: Suppose the first progenitor cell buds off two children, where one is set to be "Emit Head signals, flee from Tail signals" and the other is "Emit Tail molecules, flee from Head molecules". These two daughter-lines promptly zip off in opposite directions, and now there's a kind of chemical Head-to-Tail measure in the middle for differently-calibrated cells to arrange themselves on.
Then it buds off some cells that are tuned to create a line in-between the two poles, and those cells generate/follow a certain chemical "beat" in order to subdivide, and if the beat lasts X cycles they create X striped zones, which might become chunks of a spine...
Thing is, it seems to me like some sort of 'master control' needs to know what signals to emit. Which sounds like it has to have a 'blueprint' of what the entire organism should 'look' like?
I always think of some lil control room going "ok..we need a heart and 2 lungs...send out the heart signals, and send out 2 lung signals" (electrical or chemical or whatever the signals are)
Just amazing such 'simple' organisms manage to co-ordinate all this stuff...
Thanks! That was pretty good...gonna see what else he has :-D
ok - I have no idea what he's talking about, but both my girlfriend and I loved the ones we listened to :-D (1)(2)
I don't think this isn't fully known. Neural science has long been a fascination of mine and the conclusion I've come to is that it can happen in two ways.
The first is direct. In order for this to happen there must be a stable representation of the input and output. In this case, bright colors must have a stable representation, and fear must have a stable representation. This gives the opportunity for neurons to know how to connect the two so that one leads to the other. How does the individual neuron do that? The body is full of chemical gradients and they function kind of similar to landmarks that can be used for navigation by the growing neuron.
The second is indirect. In this case there is nothing directly encoding the connection between brightness and fear, instead due to factors of the brain structure and the environment the animal exists in it is highly likely to learn the association. For instance the low-level visual processing and fear processing areas of the brain may be almost but not quite wired up. Now there may be a common insect that is brightly colored and just a little bit poisonous. Due to the innate curiousity the animal will try to eat the insect and get an upset stomach. The dormant connection is then molded to associate these two things.
I don't see any connection between the Guardian and the recovered memory movement.
Throughout this thread you have a bit of an insistence on narrowly defining memory in terms of the brain, i.e. memories that people have.
In the field of epigenetics, and in computer science, and other areas, "memory" more broadly means a system of encoding information. Which is what happens here, when methyl groups physically bind to an adenine or cytosine molecule, like flipping a bit.
It's incorrect to call information stored in epigenetics "memories", but it's fine to call it "memory". I forgive the article for doing this as it's written for consumption by the broad public, and it's illustrative of the overall point if not literally correct.
Yes, the book is by one of the original nut bags behind the recovered memory craze. Here[1] is an academic publication talking about the problems with it.
As best we can tell through experimentation, trauma at least is passed on to subsequent generations. Comparing the science to discredited books that were based on the science and extrapolated without evidence is not a valid comparison. Like conflating UFOs with extraterrestrials, it takes a leap of faith to go from one to the other.
The article glosses over some details of a decade old study, that might have maybe shown that some types of conditioning using electrical shock might have epigenetic effects that persist in gametes and effect later behavior. The study attempts to show it indirectly and hand waves at the mechanisms. It doesn’t test for DNA methylation or anything similar.
It’s mentioned in the article here:
> How had this happened? The team discovered that the DNA in the grandfather mouse’s sperm had changed shape. … The gene for this olfactory receptor had been demethylated (chemically tagged), …
As well as in the abstract of the linked study:
> Bisulfite sequencing of sperm DNA from conditioned F0 males and F1 naive offspring revealed CpG hypomethylation in the Olfr151 gene.
I must have missed that reading the study, and that certainly is a little more compelling. I'm still very skeptical about the way the guardian article presents the claims, and the lack of any mention of follow up work since the decade old study.
> The study made use of mice’s love of cherries. Typically, when a waft of sweet cherry scent reaches a mouse’s nose, a signal is sent to the nucleus accumbens, causing this pleasure zone to light up and motivate the mouse to scurry around in search of the treat. The scientists exposed a group of mice first to a cherry-like smell and then immediately to a mild electric shock. The mice quickly learned to freeze in anticipation every time they smelled cherries. They had pups, and their pups were left to lead happy lives without electric shocks, though with no access to cherries. The pups grew up and had offspring of their own.
> At this point, the scientists took up the experiment again. Could the acquired association of a shock with the sweet smell possibly have been transmitted to the third generation? It had. The grandpups were highly fearful of and more sensitive to the smell of cherries.
I read the underlying study. It’s pretty shy on experimental details, and while an epigenetic change is the possible mechanism they don’t directly show that. It’s also a huge leap from the guardian article’s claim that memories are inherited.
> Might this new understanding increase our capacity for self-awareness and empathy? If we can grasp the potential impact of our ancestors’ experiences on our own behaviour, might we be more understanding of others, who are also carrying the inherited weight of experience?
They are literally refereeing to the concept of inherited trauma and inter-generational memory throughout the piece. It's a favorite hobby-horse of the guardian and while they are somewhat subtle here and dress it up by picking a very old study, they are in fact talking about the kind of ideas appearing in popular self help books like The Body Keeps the Score, and other things in their orbit. The author of the article in question is hawking a similar book on the guardian's books platform.
>Scientists working in the emerging field of epigenetics have discovered the mechanism that allows lived experience and acquired knowledge to be passed on within one generation, by altering the shape of a particular gene.
Also pretty debatable:
> or the trauma inflicted on your grandfather when he fled his home as a refugee, might go on to shape your parents’ brains, their behaviours and eventually yours.
Or a reference to the thoroughly academically panned The Body Keeps the Score:
> It’s not just our body that keeps the score but our very genes.
Note that I'm not claiming here that memories can be encoded in genes; I'm also not making a strong claim here that memories can be encoded epigenetically!
What I am arguing against is the claim that the only possible method of transmission of traits is through DNA, which is what parent comment said, and has been out of date for quite some time.
Your genes are a recipe book, not a blueprint. What recipe is chosen is based somewhat on environmental effects. When you reproduce, you pass on the book + the earmarks on the pages.
In your comment, the word "Explicitly" is the controversial part. Of course a memory cannot be _explicitly_ (like .mp4? lol) encoded in genetics. But effects pass on, or so says the field. It's the same as how the word "Memories" in the title is doing a lot of hand-wavey hype generation. Can I share a password or birthday party during intercourse? Of course not.
>Of course a memory cannot be _explicitly_ (like .mp4? lol) encoded in genetics.
Indeed so the answer to the question: Can you inherit memories from your ancestors? Is No. Full stop.
You want to talk about how the vibes during your grandparents lives affected some obscure part of your parents health then ok. But these things are completely different.
Maybe your grandfather had chocolate cake at his party but it turned out bad and people got sick. Now today you has an unexplained aversion to chocolate cake.
You realize this isn't an explanation of how it would happen, which is what they asked for right? All you did was give an example of what this nonsense is supposed to be.
Its not a brain memory. The argument is that epigenetic modifications can be inherited and thus the ancestor's environment is "remembered". As for how long it lasts and how much the memory is attenuated, well, that's another matter.
"Nobody would suppose that the fact that human
beings everywhere always throw their spears pointy-end first shows that there
must be a gene for a pointy-end-first instinct." - Daniel Dennett.
Counterpoint : "But, as Weiss discovered in a 2008 study, moths and butterflies can retain memories from their time as caterpillars, suggesting that the creatures' nervous system remains during the transformation into a butterfly."
That’s really not always true. And it’s disingenuous to so unequivocally write the title of a paper about mice when the headline article is about humans.
The article talks about the mouse research, I'm giving a link so people can read something other than a Guardian article and judge for themselves. Fair enough mice are different to humans but they're not exactly lobsters. (Edit: although if a similar mechanism was found in lobsters I would take that as evidence the phenomenon being widespread. It's not ethically feasible to conduct this experiment on human subjects)
Interesting! So basically: smell followed by electric shock (or some other painful stimuli) -> demethylation of (already present, but dormant?) gene that connects relevant olfactory receptor to the amygdala?
"Thus, when you and I, asleep or dozing off to sleep, fall through space and awake to sickening consciousness just before we strike, we are merely remembering what happened to our arboreal ancestors, and which has been stamped by cerebral changes into the heredity of the race."
I'm not sure where you got the take that the left thinks of it as trauma; it's consequent events (e.g. your ancestors could not get an education, job, and/or buy a house because of racism -> you did not benefit from generational wealth even though there is now less racism).
I'm also not sure where you get the far right idea from; I don't think they believe in "a sort of cultural memory", it's just culture, nothing woo about it.
TL;DR it feels like you're misrepresenting political sides to try and make this article about politics.
Exactly this. My response is usually just asking if they believe in compounding interest. It's the same concept, but with those farther up the curve justifying themselves.
Hence the "woo woo". The promise of delivery of value in the future, of which compound interest is a part of, is an invented construct that hinges entirely on people believing it to be the way things are. If people stopped believing, it would all cease to exist. There is no fundamental property of the universe that makes it so. It is merely religion.
The factors that successfulness of parents predicts successfulness of children is "woo woo".
It is not some fundamental property of the universe. It is that way only because people believe it to be the way things are. We could stop believing. It is just religion. But it seems nobody wants to, "the left" included.
Why is that? Because they are a benefactor from it? Because, as you suggest, their racist ways have "made them dumb"? The youth population – those able to offer the most future value and thus responsible for maintaining the status quo – by and large "lean left". It is not a "those other guys are to blame" situation.
I don't have beliefs, but I do acknowledge your point that actions speak louder than words. It is easy to say you are racist, but hard to do something about it, and social pattern data indicates that people are lazy and racist and therefore won't do anything[1] about it.
[1] Posting silly comments on the internet for the sake of entertainment is not doing something as it pertains to this.
The left don't think that trauma can be inherited. They think that wealth and social standing can. If your parents have money they can use their wealth to make it easier for you to have money
If your parents are poor (perhaps due to racism) then you will live in a poor area with worse schools, possibly contaminated with pollution, subject to higher insurance and basic costs.
This doesn't require magic ancestral memories it just requires ecomonics.
(Not trying to pose this as a left/right thing - but rather "this is a thing" - and these aren't memories but rather the result of epigenetic changes to the expression of hormones and neurotransmitters that may be able to be passed from mother to child and exhibit differences in how one reacts to certain stimuli)
> The left don't think that trauma can be inherited.
Well, some of them do, as otherwise they would not have told me about it at length in conversation. Scientific literacy varies greatly within every political camp.
I don't know if you can speak for the entire left here, it's really not hard to find articles from the 2010s from otherwise fairly respectable progressive publications which are pretty confident. Usually when I've heard ideologically minded people talking about "transgenerational trauma" [1], it's from a lens of epigenics. I don't think anyone would reasonably doubt that wealth or poverty ripples through many generations, the idea which I hear touted pretty frequently (and is discussed in the article), is that past trauma from war, famine, racism, etc. has a biological mechanism which explains disparities we see today.
As others have pointed out, it's a super convenient conclusion for folks who seek to understand the world in such a way, but at least presently the data just isn't there.
I've never heard any of these ideas. The question in the title is nonsense and you are skewing and distorting other ideas into more nonsense to make something that is already ridiculous political.
This is analogous to when we inherit an old application without the git history and the original developers are long gone. Our instincts are a bunch of logic rules encoded into our DNA like "If you see a python snake, run away".
Can anyone verify that studies have shown that trauma can be inherited from male parents? I had been assuming epigenetic memory came from mothers, via chemical signaling during pregnancy. But epigenetic memory from fathers must be from actual changes to the DNA? Fascinating that a trigger like 'the smell of cherries' can be stored that precisely. It is very hard to believe, so relying on the scientific method here.
The most compelling evidence of any epigenetic changes influencing offspring were the animal studies that showed trauma to the mother can be evident two generations later in premature maturation of memory systems of male offspring (i.e., grandsons). As you state this is via the maternal line at first, I will need to check if the inbetween carrier was female or male. Rick Richardson has done a lot of work on this, here is one paper but I'd suggest looking at his further work; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3637360/
My favorite footnote from Entangled Life [1] (a great book mostly about fungal relationships) is about tapeworm memories: scientists can train them to solve mazes, cut off their heads [which re-spawn], and the trained maze memories are still implemented by the new neuronal cluster ("brain").
178 comments
[ 4.3 ms ] story [ 215 ms ] threadHere's a quote from the article:
> Scientists working in the emerging field of epigenetics have discovered the mechanism that allows lived experience and acquired knowledge to be passed on within one generation
This is obviously such a nonsense interpretation of epigenetic changes that it's hard to take anything in the article seriously.
Obviously there's real science happening around epigenetics and there are interesting findings, reporting like this is a really big leap.
[1] https://en.wikipedia.org/wiki/Recovered-memory_therapy
[2] https://www.nytimes.com/2022/09/27/opinion/recovered-memory-...
No one (including you) really knows the whole extent of epigenetic effects, so I would suggest you give it another read.
We are still at (estimate) 10% known / 90% unknown in Biology. Source: Biologist for 20 years now.
Btw, read the site guidelines. This is a place for discourse, not berating others.
[1] https://www.quantamagazine.org/insect-brains-melt-and-rewire....
I don't. You're attacking a straw man.
You wrote,
>Erm…memories — by any biologically reasonable definition— are separate from epigenetic changes.
I replied with a study showing the opposite to be true.
You’re selectively quoting and then re-arranging the quotes to attempt to make yourself look better.
Honestly, for someone to be posting this nonsense with a link to their LinkedIn professional profile in their bio is kind of career suicide. You’ve inadvertently stumbled into an argument on a IT tech website with people who are bona fide life scientists and are embarrassed and are clumsily trying to save face.
Feel free to add me on LinkedIn, I have no issue in people knowing who I am; should I be scared or anything? Lol. You should try not being anonymous, just a suggestion, :).
You said:
"Memory [...] is separate from epigenetic changes"
I replied with a study that seems to suggest otherwise. That's not really hard to follow ...
>IT tech website
Hmm naw man, Hacker News is way more than that. Also, why would I be embarrassed? You are just projecting too much unto others, chill.
Nope.
The 2008 study is "the first to demonstrate conclusively that associative memory survives metamorphosis in Lepidoptera".
The article you cited does not disprove this, but rather it shows the brain structure of (some, at least) insects get completely re-arranged before/after their transition to adulthood.
For me, this only makes the 2008 study more interesting, since the memories could still persist, even after a completely new brain architecture (!).
But if we're going to do that, let's do it properly and choose the peer reviewed article written by experts in the field over a blog post written by a "science communicator".
¯\_(ツ)_/¯
But I do work as a researcher, publish some interesting papers from time to time and, yes, I think I'm also an "app developer", in the sense that I've made some apps?
These kind of arguments you make really come across as quite infantile, to be honest. I'm going to have to stop engaging with you because no substantial value is added to the conversation while you already crossed the line to personal attacks, several times, even after you've been told about it and pointed to this site's rules. Find somebody else to engage with your tantrums, I'm out.
cc @dang?
https://news.ycombinator.com/item?id=40720177
https://news.ycombinator.com/item?id=40713066
https://news.ycombinator.com/item?id=40713015
I'm not commenting on whether you're right or wrong about biology, obviously—I have no idea. But it's not ok to violate HN's rules like this, regardless of how right you are or feel you are. I appreciate that you've been a biophysicist for 30 years and we certainly want that people with that depth of expertise on HN, but even more important is that you not put down or ridicule others.
I know that in the history of science and academia there has at times been a culture of hard-nosed ridicule of others who are deemed to be wrong and/or not knowledgeable enough to enter a discussion. Perhaps that approach is still vital in some professional circles, maybe? I don't know, but I can tell you for sure that on an open internet forum like HN, such an approach just poisons everything it touches.
Incidentally, if you do happen to be right, that makes it even worse to post these sorts of attacks, because then you end up giving people a reason to discredit you which has nothing to do with the truth. Lots of past explanation about this if anyone cares: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor....
You've broken the site guidelines since then too, so this is unfortunately a pattern:
https://news.ycombinator.com/item?id=40744320
https://news.ycombinator.com/item?id=40739423
If you wouldn't mind reviewing https://news.ycombinator.com/newsguidelines.html and taking the intended spirit of the site more to heart, we'd be grateful.
"Epigenetic memories" is different than colloquial "memories". The article seems to completely miss this. And of course people who haven't been exposed to that domain specific concept are likely to misinterpret it.
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3923835/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7225062/
Ok, now this is something!
So, please enlighten me, what could be the political agenda being pushed by an article pondering around whether memories can be inherited or not?
"Epigenetic memory" is the term of art I was taught in grad school. Either they've changed that in the last 10 years, or ch4s3 is attempting to assert a different definition of "memory" than the one used in the field.
They are also incorrect. DNA methylation is an actual methyl group chemically binding to an actual DNA nucleotide, and staying there. When we flip a bit on a hard drive platter we call that "memory" as well.
[0] https://scholar.google.com/citations?user=MJO2lYIAAAAJ&hl=en
Do I have a wholly-incorrect understanding of epigenetics? Is there a clear and simple example of an epigenetic mechanism?
Inherited trauma is totally unsupported but up or down regulated gene expression based on environmental factors before your conception are supported by some compelling evidence.
Your genes are a recipe book, not a blueprint. What recipe is chosen is based somewhat on environmental effects. When you reproduce, you shuffle together the parents book + the earmarks on the pages.
This is only true if you take a pretty narrow definition of the word "trauma".
One example would be an ancestor experiencing famine, who then passes down epigenetic markers have marked effects on their offspring in terms of health, longevity, and behavior.
Here's a Nature article on it: https://www.nature.com/articles/s41418-023-01159-4
> "Collectively, these discoveries infer the existence of “a heritable memory of starvation/hunger”."
Also the phrase "a heritable memory" is kind of nonsense even with respect to epigenetic changes. Again what we're talking about with epigenetics is up or down regulation of your existing genes, not some new information being encoded.
I fully agree that someone starving to death right around the time of pregnancy could have some knock on effects; this is discussing changes in the following generation, the ones that are tens of years removed from the starvation event.
> Also the phrase "a heritable memory" is kind of nonsense even with respect to epigenetic changes. Again what we're talking about with epigenetics is up or down regulation of your existing genes, not some new information being encoded.
I wonder if you are missing the forest for the trees here somewhat. We're talking about the up/down regulation of specific genes based on specific methylation patterns in DNA that are present only because of some event that occurred. It's not memory in the sense of "I remember what I had for breakfast this morning", but it's memory in the sense of "these methylation patterns exist because their genesis was triggered by a specific event in the last few generations". That IS new information being encoded, just in a more fuzzy way than with neurons or computer memory.
I would need more convincing to think the phrases you mention are nonsense/bunk. Could you perhaps articulate the definitions you're using for "trauma" and "memory"? I think we are using different definitions, as it seems clear what is meant by the phrases as used.
EDIT: what issue do you take with the Dutch hunger study? I hadn't heard criticism about it before, and I just googled "dutch hunger cohort study criticism" and found nothing.
x2
@ch4s3 is making some pretty strong claims here and there, for which I do not see the evidence either.
Don't take me wrong, I don't mean to suggest he's just being a quack; but rather, this is an invitation for him to substantiate his knowledge. The more we learn the better, :).
My criticism is that a lot of studies based on the data to lazy things like this, draw big conclusions, and get a lot of citations but there just isn’t much to them.
[1] https://scholar.google.com/scholar?hl=en&as_sdt=0%2C39&q=%E2...
Wooos, posted the wrong link earlier. https://obgyn.onlinelibrary.wiley.com/doi/abs/10.1111/1471-0...
I really don't have the time or energy to go through all of them, tbh.
¯\_(ツ)_/¯
I think "in the last few generations" is a little speculative. There's strong evidence for epigenetic changes being passed from parents, but going further back the evidence is much weaker.
> what issue do you take with the Dutch hunger study
It's a really narrow study of a rather genetically homogeneous group picked from a really small geographic area and it has all of the issues of any retrospective study. The outcome could just be random chance. If you look at any small closely related group you're just going to find some sort of weird clustering, even if it varies in that group. If similar epigenetic markers showed up in other populations with similar well documented circumstances it would be stronger.
https://en.wikipedia.org/wiki/%C3%96verkalix_study
The classic example of epigenetics - of stable information transfer between cell generations not based on DNA sequence - is methylation of cytosines. Here's the simplified version. As you know, the DNA is based on ACTG. When you have a CG, the C can be methylated, which means an extra carbon is attached at a specific position on the molecule. That extra carbon gets 'copied' when the DNA is duplicated during mitosis and gets passed to the daughter cells. Yet it can be added or erased during the cell's lifetime. It typically works to block proteins responsible for transcribing genes into mRNA from binding to the gene, so the gene is silenced when it is methylated. This gives a way to transmit patterns of gene expression across generations of cells.
This mark is extremely well-studied and understanding everything about DNA methylation is beyond this humble PhD student. But there are also extremely mechanisms for erasing and/or resetting certain aspects of cell state during mitosis or meiosis, including RNA, the proteome, and methylation state. We can't take it for granted that just because there's a mechanism by which biochemical information could be transmitted that it actually is (or that it isn't).
A common source for the idea of intergenerational trauma being supported by epigenetic evidence is the Dutch hunger winter [1]. The idea is that an experience that parents had in utero seems to have had an effect on the physical development of their children, in a way that's specific to parental sex. I'm willing to say "sure, that effect could be real and there could be an epigenetic explanation." But AFAIK we don't know specifically what that hypothetical mechanism would have been.
Note that the bod(y|ies) of the mother and child are interchanging material and engaging in biochemical crosstalk constantly during gestation, so there is abundant opportunity for environmental influences on the mother to have lifelong impacts on the child. Since the child's body will in turn engage in the same 'dialog' with the child's own children during fertilization and gestation, it's entirely possible for environmental influences on generation 1 to impact generation 3 as mediated by generation 2 via an in utero exposure.
All that said, I have a lot of uncertainty about what our priors ought to be on how important such hypothetical mechanisms might be. I think that in the coming decades, we'll make huge progress in understanding development and disease within an individual's body through an epigenetic lens. We will probably also see some interesting controlled experiments on "epigenetic inheritance" using short-lived model organisms, such as fruit flies or worms. Possibly we will collect enough epigenetic information in large-scale biobanks over 20-40 years that we can get a more detailed understanding of possible epigenetic inheritance mechanisms in humans, but these assays are currently quite expensive, and moreover there's no single measure applicable to an individual person, since the whole point of epigenetics is that the state varies across cell and tissue type.
[1] https://www.ohsu.edu/school-of-medicine/moore-institute/dutc...
It's one thing to suggest that psychological or metabolic stress could affect the dynamics of DNA methylation in a way that crosses generational boundaries. It's quite another to identify those inherited dynamics as "memories".
:-)
People say 'instinct' by never mention what that means or how it works :-P
For spiders then there is an action pattern that upon certain stimulus they will use their spinnerets begin forming a web, first placing anchor points and gradually building it up with radial threads and spiral. The exact behavior differs by species such that they have different resulting patterns. It seems possible that there is an element of 'learning' beyond the basic pattern as well, even in seemingly very simple animals.
I doubt the spiders have a mental model of what their web looks like as such, it's more evolutionary driven genetic behavior, a particular neuronal pattern encoding the action sequence rather than an underlying fundamental understanding.
>For spiders then there is an action pattern that upon certain stimulus they will use their spinnerets begin forming a web, first placing anchor points and gradually building it up with radial threads and spiral.
I can sorta understand stimulus causing them to start making a web (sorta like stimulating a mammary can cause lactation) - but how do it 'know' to use a radial pattern rather then ah-hoc mess the black widows on my porch make? The 'ad-hoc' pattern seems like it would be more 'likely' then a nice pattern? Overall, I guess it just seems like a rather complex pattern/behavior?
Also, I guess I have a more basic question of 'what is instinct' if its not some sort of 'memory'? People seem to have an 'instinct' of the mechanics of throwing a ball, yet we have wildly different abilities with regards to accuracy, 'form', distance/speed (due to muscalture?) - it just seems like we have an 'instinct' for the 'simple' mechanical movements but not for the more complex behavior like throwing a ball to hit a target ?
Thanks again!
I think throwing a ball is more learned, although some behaviors like grasping the ball may provided a fixed action foundation on which higher order learning builds. Baby humans have a grasp reflex that works in a similar way to the fixed action pattern described, but with a simpler action sequence. If you touch the palm of a toddler, they will instinctively tightly grasp. It's interesting that the grasp reflex disappears around 5 years old, so the fixed neuronal pattern is subsumed by higher order learned behavior.
Thats where I get stuck..the 'behavior' has to account for different sizes of webs (the spider might be in a tight space, or a more open space), etc.
That just seems like an incredibly complex behavior to encode...Cells are supposedly 'simple' organisms but they manage to create/manage such complex behaviors...it's mind blowing..
Thanks!
My guess: It "just feels right".
In the beginning (?), the species didn't have any "preference" and just did whatever. Some species cut the pizza in circles (as in, cutting out a circle from inside the pizza, leaving a donut-shaped pizza), others cut squares, others cut weird shapes, etc. All over the place.
Over time, those predisposed to cutting the pizza in a straight line, from border to border, passing through the center, began to survive slightly longer than the rest (for some unknown reason), becoming the dominant predisposition. To anyone born since then, it just felt right to cut the pizza that way. Not passing through the center of the pizza was just weird. And stopping a cut midway, without going all the way through, was also just weird.
At that point the amount of cuts still varied though, so it was all over the place. Some cut it in half, other made 2 cuts (4 slices) but they were in ugly 20° angles (so 2 huge slices and 2 small slices), others made hundreds of cuts so each piece was tiny and was annoying to eat, stuff like that.
Over time, those who preferred to cut the pizza in 90° angles started to survive slightly longer, and over time became the dominant predisposition.
And so on and so on. With these learnings it was becoming easier for people to make pizza ("find food"). Pizza sizes increased, and so did the amount of people sharing a single pizza. Making it easier to attract others, and share a pizza with them. Meeting more people makes it slightly more likely to find a life partner.
Time passed, same old song and dance. Now all pieces must be symmetrical. It was the most fair way to share. Not doing it this way meant the one doing the cuts was evil and must be avoided.
Current situation: Most people cut the pizza in 8 equal-ish slices because it just feels right to do it that way. Those who don't do it that way might still reproduce, but are slightly more likely to be avoided because they are weirdos. They are also slightly less able to get food, because nobody wants to share their pizza with those weirdos, so they are slightly more likely to starve due to being unable to "attract" food.
In that parallel universe, someone named 224hcem asks:
> But how do they "know" to cut the pizza in 8 equal slices rather than the ad-hoc mess the teenagers next door make with their microwaved pizza? Overall it's way more effort to try to make all pieces nice and equal, and the movements have to be more precise meaning the brain calculations are more complex compared to just winging it.
Thanks
And the more complex the behavior the more it blows my mind :-D
Thanks!
Thanks for the link below - it was pretty neat :-D
A chaotic web is a sign that the black widow spider is well fed and not hungry.
Thanks
In any case here's a discussion of said paper.
https://www.nationalgeographic.com/science/article/death-tra....
This is fascinating stuff.
>Is it possible that these are based on inherited memories, patterns, insticts of dinosaurs?
It is possible that these are based, at least in part, on the discovery of dinosaur fossils, but humans didn't even evolve until the dinosaurs were long dead. So even if it were possible for "inherited memory" to include visual memories it wouldn't do so for dinosaurs.
It doesn't seem likely that whatever primitive mammalian ancestor eventually evolved into primates, and then into humans, carried within it a coherent enough visual and behavioral memory of dinosaurs to have survived so many generations of mutation, eventually informing the modern idea of "dragons" as winged reptiles.
And again, it isn't even true that there is a cross-cultural concept of "dragons" to begin with. It's a eurocentric myth, in that it assumes a Western concept of a "dragon" to be the default, and ignores any other cultural context in order to fit their mythologies into that mold.
Also, humans don't instinctively understand that fire can be dangerous, so there's that.
I didn't realize people don't have an instinct about fire. I always thought kids touching hot stoves/fire was because their hands touched it before their brains registered 'hot! ouch!'
>>and thus can learn some things("instinctual behaviour") easier than others
I don't understand this - Isn't 'instinctual behaviour' something you don't have to learn? Also, I wonder if there's a limit to how complex a behavior can be 'encoded'? like bright colored animals == poisonous. That requires being able to tell a say a toad from a bird, what a color is, what colors = poison, etc? That seems like a pretty complex behavior...Do we have any idea what the limit is for complex behaviors in genes?
Thanks!
AFAIK the current explanations for this often involve electrical and chemical gradients, along with "timer" cyclic reactions among groups of cells.
A contrived example: Suppose the first progenitor cell buds off two children, where one is set to be "Emit Head signals, flee from Tail signals" and the other is "Emit Tail molecules, flee from Head molecules". These two daughter-lines promptly zip off in opposite directions, and now there's a kind of chemical Head-to-Tail measure in the middle for differently-calibrated cells to arrange themselves on.
Then it buds off some cells that are tuned to create a line in-between the two poles, and those cells generate/follow a certain chemical "beat" in order to subdivide, and if the beat lasts X cycles they create X striped zones, which might become chunks of a spine...
I always think of some lil control room going "ok..we need a heart and 2 lungs...send out the heart signals, and send out 2 lung signals" (electrical or chemical or whatever the signals are)
Just amazing such 'simple' organisms manage to co-ordinate all this stuff...
Thanks
There's also this parody video of Despacito [1] that may be, er, educationally amusing.
[0] https://en.wikipedia.org/wiki/Homeobox
[1] https://www.youtube.com/watch?v=ydqReeTV_vk
Thanks again!
1) https://www.youtube.com/watch?v=2rjbtsX7twc
2) https://www.youtube.com/watch?v=f8FAJXPBdOg
Have you never been afraid of spiders or snakes?
https://www.cbs.mpg.de/Fear-of-spiders-and-snakes-is-deeply-...
The first is direct. In order for this to happen there must be a stable representation of the input and output. In this case, bright colors must have a stable representation, and fear must have a stable representation. This gives the opportunity for neurons to know how to connect the two so that one leads to the other. How does the individual neuron do that? The body is full of chemical gradients and they function kind of similar to landmarks that can be used for navigation by the growing neuron.
The second is indirect. In this case there is nothing directly encoding the connection between brightness and fear, instead due to factors of the brain structure and the environment the animal exists in it is highly likely to learn the association. For instance the low-level visual processing and fear processing areas of the brain may be almost but not quite wired up. Now there may be a common insect that is brightly colored and just a little bit poisonous. Due to the innate curiousity the animal will try to eat the insect and get an upset stomach. The dormant connection is then molded to associate these two things.
Throughout this thread you have a bit of an insistence on narrowly defining memory in terms of the brain, i.e. memories that people have.
In the field of epigenetics, and in computer science, and other areas, "memory" more broadly means a system of encoding information. Which is what happens here, when methyl groups physically bind to an adenine or cytosine molecule, like flipping a bit.
It's incorrect to call information stored in epigenetics "memories", but it's fine to call it "memory". I forgive the article for doing this as it's written for consumption by the broad public, and it's illustrative of the overall point if not literally correct.
FYI, the author is a respected neuroscientist: https://en.wikipedia.org/wiki/Hannah_Critchlow
It’s a comparison.
Respected or not she’s making the argument the “the body keeps the score,” which is redolent of the discredited book of the same name.
The body keeps the score is discredited?
[1]https://pubmed.ncbi.nlm.nih.gov/16483114/
It’s mentioned in the article here: > How had this happened? The team discovered that the DNA in the grandfather mouse’s sperm had changed shape. … The gene for this olfactory receptor had been demethylated (chemically tagged), …
As well as in the abstract of the linked study:
> Bisulfite sequencing of sperm DNA from conditioned F0 males and F1 naive offspring revealed CpG hypomethylation in the Olfr151 gene.
https://pubmed.ncbi.nlm.nih.gov/24292232/
> The study made use of mice’s love of cherries. Typically, when a waft of sweet cherry scent reaches a mouse’s nose, a signal is sent to the nucleus accumbens, causing this pleasure zone to light up and motivate the mouse to scurry around in search of the treat. The scientists exposed a group of mice first to a cherry-like smell and then immediately to a mild electric shock. The mice quickly learned to freeze in anticipation every time they smelled cherries. They had pups, and their pups were left to lead happy lives without electric shocks, though with no access to cherries. The pups grew up and had offspring of their own.
> At this point, the scientists took up the experiment again. Could the acquired association of a shock with the sweet smell possibly have been transmitted to the third generation? It had. The grandpups were highly fearful of and more sensitive to the smell of cherries.
> Might this new understanding increase our capacity for self-awareness and empathy? If we can grasp the potential impact of our ancestors’ experiences on our own behaviour, might we be more understanding of others, who are also carrying the inherited weight of experience?
They are literally refereeing to the concept of inherited trauma and inter-generational memory throughout the piece. It's a favorite hobby-horse of the guardian and while they are somewhat subtle here and dress it up by picking a very old study, they are in fact talking about the kind of ideas appearing in popular self help books like The Body Keeps the Score, and other things in their orbit. The author of the article in question is hawking a similar book on the guardian's books platform.
Claims don't have question marks.
But since there are so many such statemetns, feel free to post a few examples.
>Scientists working in the emerging field of epigenetics have discovered the mechanism that allows lived experience and acquired knowledge to be passed on within one generation, by altering the shape of a particular gene.
Also pretty debatable:
> or the trauma inflicted on your grandfather when he fled his home as a refugee, might go on to shape your parents’ brains, their behaviours and eventually yours.
Or a reference to the thoroughly academically panned The Body Keeps the Score:
> It’s not just our body that keeps the score but our very genes.
Note that I'm not claiming here that memories can be encoded in genes; I'm also not making a strong claim here that memories can be encoded epigenetically!
What I am arguing against is the claim that the only possible method of transmission of traits is through DNA, which is what parent comment said, and has been out of date for quite some time.
Your genes are a recipe book, not a blueprint. What recipe is chosen is based somewhat on environmental effects. When you reproduce, you pass on the book + the earmarks on the pages.
In your comment, the word "Explicitly" is the controversial part. Of course a memory cannot be _explicitly_ (like .mp4? lol) encoded in genetics. But effects pass on, or so says the field. It's the same as how the word "Memories" in the title is doing a lot of hand-wavey hype generation. Can I share a password or birthday party during intercourse? Of course not.
Indeed so the answer to the question: Can you inherit memories from your ancestors? Is No. Full stop.
You want to talk about how the vibes during your grandparents lives affected some obscure part of your parents health then ok. But these things are completely different.
With our current knowledge, we cannot either prove or disprove this.
But if you want a nuanced discussion of the article, we should soften the gaze a little. That's all I'm saying.
We would still be cavemen with that attitude.
Counterpoint : "But, as Weiss discovered in a 2008 study, moths and butterflies can retain memories from their time as caterpillars, suggesting that the creatures' nervous system remains during the transformation into a butterfly."
"Parental olfactory experience influences behavior and neural structure in subsequent generations" (2014)
"[...in mice]"
https://www.gutenberg.org/files/310/310-h/310-h.htm
https://youtu.be/jq1Z--HQp5k?t=9
The far right to suggest that there is a sort of cultural memory that immigrants can never integrate with.
The far left to suggest a kind of cultural trauma that requires affirmative action.
I'm also not sure where you get the far right idea from; I don't think they believe in "a sort of cultural memory", it's just culture, nothing woo about it.
TL;DR it feels like you're misrepresenting political sides to try and make this article about politics.
The single greatest indicator of a person's financial success is that of their parents. And that simply repeats generation after generation.
There's nothing magical about it.
I hate racism. It makes people dumb.
It is not some fundamental property of the universe. It is that way only because people believe it to be the way things are. We could stop believing. It is just religion. But it seems nobody wants to, "the left" included.
Why is that? Because they are a benefactor from it? Because, as you suggest, their racist ways have "made them dumb"? The youth population – those able to offer the most future value and thus responsible for maintaining the status quo – by and large "lean left". It is not a "those other guys are to blame" situation.
LOL. You don't believe in social patterns?
Ok, well, you might be the only one. I hope you don't invest in stocks or try to start your own company. Or have friends.
[1] Posting silly comments on the internet for the sake of entertainment is not doing something as it pertains to this.
If your parents are poor (perhaps due to racism) then you will live in a poor area with worse schools, possibly contaminated with pollution, subject to higher insurance and basic costs.
This doesn't require magic ancestral memories it just requires ecomonics.
The epigenetic reaction to trauma is something that may be able to be inherited.
Epigenetic transmission of Holocaust trauma: can nightmares be inherited? - https://pubmed.ncbi.nlm.nih.gov/24029109/
Study finds epigenetic changes in children of Holocaust survivors - https://www.research.va.gov/currents/1016-3.cfm
How Parents’ Trauma Leaves Biological Traces in Children - https://www.scientificamerican.com/article/how-parents-rsquo...
Mechanisms of Epigenetic Inheritance in Post-Traumatic Stress Disorder - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10817356/
(Not trying to pose this as a left/right thing - but rather "this is a thing" - and these aren't memories but rather the result of epigenetic changes to the expression of hormones and neurotransmitters that may be able to be passed from mother to child and exhibit differences in how one reacts to certain stimuli)
Well, some of them do, as otherwise they would not have told me about it at length in conversation. Scientific literacy varies greatly within every political camp.
As others have pointed out, it's a super convenient conclusion for folks who seek to understand the world in such a way, but at least presently the data just isn't there.
[1] https://en.wikipedia.org/wiki/Transgenerational_trauma
Can anyone verify that studies have shown that trauma can be inherited from male parents? I had been assuming epigenetic memory came from mothers, via chemical signaling during pregnancy. But epigenetic memory from fathers must be from actual changes to the DNA? Fascinating that a trigger like 'the smell of cherries' can be stored that precisely. It is very hard to believe, so relying on the scientific method here.
[1]: https://www.amazon.com/Entangled-Life-Worlds-Change-Futures/...