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Thursday, July 3, 2014

After Darwin, Lamarck: New Evidence That Bad Memories Can Be Genetically Transmitted

Posted by on Thu, Jul 3, 2014 at 8:32 AM

After being ruled for 80 years by a gene-centric form of Darwinism, the biological sciences might be at the dawn of a new age of Lamarckism. You do not believe me (one who sides with the developmental systems thinking of Susan Oyama and Richard Lewontin)? Well check out what a study conducted at Emory University School of Medicine, and published in the journal of Nature Neuroscience, found:

[Researchers] trained mice to fear the smell of cherry blossom using electric shocks before allowing them to breed.
The offspring produced showed fearful responses to the odour of cherry blossom compared to a neutral odour, despite never having encountered them before.
The following generation also showed the same behaviour. This effect continued even if the mice had been fathered through artificial insemination.
The researchers found the brains of the trained mice and their offspring showed structural changes in areas used to detect the odour.
This is not Darwinism, this as close to Lamarck as science can get. Lamarck, if you remember, believed that the living experiences of a parent could be passed down to his/her offspring. The idea was only allowed a home in cultural evolution, and banned from anywhere near biological evolution. But combine these striking findings at Emory University School of Medicine with those recently appearing in the emerging field of epigenetics, and you are pretty much looking at the next era of evolutionary biology, an era that will find the thinking of Susan Oyama more useful than that of Richard Dawkins and his science fictional survival robots.

Also, these findings may actually do a number on the whole mind modules thing that's pushed by the leading proponents of evolutionary psychology.

 

Comments (23) RSS

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1
That's an interesting study but did they take into account that maybe the parents taught them to fear the smell? If the baby mice were still raised by the parents (baby needs to breast feed at least right?) then maybe the parents taught this to them. I don't know either way but it seems more likely than genetically passed on memories.
Posted by Root on July 3, 2014 at 8:58 AM · Report this
2
I think that is what they were addressing when they said it was passed on even through artificial insemination.
Posted by wl on July 3, 2014 at 9:08 AM · Report this
seandr 3
@1: Having just read the Nature article, they make some effort to rule that possibility out by examining IVF offspring of fear-conditioned males (i.e., neither the offspring nor the mothers ever encountered the fathers), and they noted that these offspring showed the same markers in brain anatomy, but they didn't test whether offspring actually feared the odor:

"We could not perform behavioral analyses on IVF-generated offspring because of animal quarantine issues."


Oops! So yes, the verdict is still out on whether this is genetic or social learning.
Posted by seandr on July 3, 2014 at 9:23 AM · Report this
unknown_entity 4
Me, personally, I have always felt that evolution being 100% caused by random gene mutations passed on genetically could not be the answer. Not that there was "intelligent design," but that there must be some sort of feedback mechanism that could influence how genes mutated or, in this case, created an instinctual behavior.
Posted by unknown_entity on July 3, 2014 at 9:30 AM · Report this
blip 5
It's not genetics, it's epigenetics: chemical modification of genes that regulates their expression that do not in any way alter the sequence of the underlying DNA (genetics). These modifications can be passed on for generations.
Posted by blip on July 3, 2014 at 9:34 AM · Report this
6

I think of concepts like entanglement (as nicely summarized in the book Biocentrism.

Two entangled particles, can have parallel behavior choices,, with effects that can in fact, precede the observation by a human at speeds faster than light.

The concept of entanglement has been mathematically established since Bell in the 1960s, but there are a number of experimental verifications since 2000.

So then I think of chromosomes. What could be more "entangled" than two strands of DNA (and yes, I know, the genetic chemical bonding is not quite the same as entangled electrons...or is it...)
Posted by Supreme Ruler Of The Universe http://_ on July 3, 2014 at 9:39 AM · Report this
7
@3, figures
Posted by GermanSausage on July 3, 2014 at 10:47 AM · Report this
Tingleyfeeln 8
I don't think this dismisses gene mutation, it offers a possible explanation for the cause of gene mutation.
I've contemplated for years the role of ancestral experiences in our lives. On a personal level, this idea is about the only explanation I've been able to come up with for some of my characteristics that seem out of line with my up ringing.
As for the competing theories of evolution, lets not have this turn into a rehash of the old "nature vs. nurture" argument. Lets save the black and white thinking for the less evolved among us.
Posted by Tingleyfeeln on July 3, 2014 at 10:59 AM · Report this
9
Mudede, please, for the love of the FSM, stay the heck away from opining about evolutionary theory until you've spent a considerable time learning about it, and not from screeds and popular science literature. One tip: if you're talking about Dawkins, you're more likely than not doing it wrong (he's always been more of a popularizer than a serious thinker, and he's disappeared into his own bunghole in the pursuit of controversy and attention in recent years). You've traveled down this road before, and haven't fared well.
Posted by Warren Terra on July 3, 2014 at 10:59 AM · Report this
venomlash 10
@5: Right on the money. A classic example of epigenetics would be metabolic rates; the children of malnourished individuals tend to have stingier metabolisms because of epigenetic tagging as a result of their parents' environments.
@6: JBITSMFOTP and doesn't understand that things work differently on micro- and macroscales.
Posted by venomlash on July 3, 2014 at 11:06 AM · Report this
Charles Mudede 11
@9) if you think im writing to scientists, you are insane. im writing to the public and, sadly, dawkins is a public figure. scientists are at once smart and terribly naive.
Posted by Charles Mudede on July 3, 2014 at 11:18 AM · Report this
blip 12
@8, I haven't read the paper but I assume they would rule out genetic mutation by sequencing the genes in exposed/unexposed mice as well as their progeny, in addition to demonstrating that the gene involved in detecting the odor has been epigenetically modified.
Posted by blip on July 3, 2014 at 11:26 AM · Report this
13
@11 Wow, way to miss the fucking point. First of all, @9 doesn't classify your audience at all. S/he says nothing about your audience actually, so the idea that @9 is accusing you of writing for scientists is a complete non sequitur.

More disturbingly, you argue that because you are writing to the lay public, you must for some reason only use sources that are "public figures". Does this mean you'll be quoting Jenny McCarthy when you post about vaccines?
Posted by Solk512 on July 3, 2014 at 12:09 PM · Report this
treacle 14
I always knew that Lamarck was right, somehow. And here he is, being vindicated at last. It even mentions his vindication on the Wikipedia page about epigenetics.
Posted by treacle on July 3, 2014 at 12:25 PM · Report this
15
My working assumption is that this study will work out to be flawed in some way. Epigenetics does not easily explain the result as described in the news report - sure, there can be activity-dependent changes in gene expression that can be stable across multiple generations of cell division - but this does nothing to explain how such a change in the nervous system (olfaction, pain perception, cognition) would be transmitted to the germline, which separated its lineage from those tissues long before the exposure. Some mechanisms known to exist in other systems (RNA transport, potentially leading to microRNA-directed epigenetic changes in distant tissues) are not known to exist in mammals, and would be a highly hypothetical stretch in any case.

On the other hand, a fairly trivial explanation would be if the animals' exposure to the chemical was not limited to the olfactory bulb, but was in fact systemic. In this case, the oocytes could have expressed the receptor and thereby responded to the odor, leading to epigenetic changes in gene expression. This would be roughly consistent with the results as seen from a quick glance at the abstract (which is NOT to say it constitutes a devastating critique not addressed someplace in the paper). Importantly, it's not clear from the abstract that the word "conditioning" is justified, at least as popularly understood (Pavlovian paired conditioning, a learning-and-memory task); I don't know how the term is used properly in the neuroscience literature.

Absent either a genuine transmission of a trained response (rather than merely evidence of prior exposure) or proof that the exposure and detection of same was limited to the olfactory system (and there are approaches for this that should work), this might be rather a boring paper.
More...
Posted by Warren Terra on July 3, 2014 at 1:08 PM · Report this
word3 16
Epigenetic marks are laid down at a number of times during development including during gametogenesis. It is not necessary to invoke olfactory receptors on oocytes or spermatocytes to explain alterations in the regulation of the genes controlling epigenetic modifications that occur during gamete formation.

I think Charles does an awesome job writing for both scientists and non-scientists.
Posted by word3 on July 3, 2014 at 2:11 PM · Report this
17
@#16
Sorry, no. That epigenetic marks are laid down during gametogenesis is true, but it's moot. The point of the study is that exposure to this olfactory cue triggers heritable changes in the expression of the gene encoding the receptor, apparently via changes in DNA methylation at that gene. If the exposure is not being sensed in tissues that give rise to gametes, this is a startling result. If the exposure is being sensed in tissues that give rise to gametes, it's really not all that surprising. The news report of heritable effects of paired conditioning strongly suggests the former is being claimed.
Posted by Warren Terra on July 3, 2014 at 2:17 PM · Report this
18
My god, Assassin's Creed was right all along!
Posted by Hacksaw on July 3, 2014 at 2:43 PM · Report this
seandr 19
@9, @13: OMG, will you lopsided pair of tits please shut the fuck up already?

This is an great post on a fascinating bit of science. If you don't like it, eat my asshole.
Posted by seandr on July 3, 2014 at 4:07 PM · Report this
20
@16, I have a doctorate of philosophy in a hard science, and think Charles does a dreadful job of summarizing the experiments while he tries to spin Lamarckism as completely out of favor. In some cases, theories postulated by Lamarck (and others before him) may have a connection.... even wikipedia cites 2009 as lamarck and epigenetics as being similar. http://en.wikipedia.org/wiki/Lamarckism
Posted by ChefJoe on July 3, 2014 at 4:41 PM · Report this
21
Trying to put a connection to this theory into the republican hysteria for voting for the stupidest persons on the ballot. Could be a breakthrough, maybe there is a drug to counteract the insanity gene in the republican party?
Posted by longwayhome on July 3, 2014 at 8:06 PM · Report this
venomlash 22
@20: What science, and from what university? If you'll humor my curiosity, that is.
Posted by venomlash on July 3, 2014 at 10:41 PM · Report this
word3 23
@17 It is not a startling result, it simply remains to be shown precisely how the olfactory exposure triggers these changes.
It is perfectly possible to elicit changes in gene expression in one tissue indirectly via stimulous of another tissue. gametogenesis and the comensutate changes in gene that occur during that process are driven by both local and remote signals.
Posted by word3 on July 4, 2014 at 7:08 AM · Report this

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