
Mice can inherit learned sensitivity to a smell (2013) - marojejian
http://www.sciencedaily.com/releases/2013/12/131202121544.htm
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anateus
I've read the paper. We don't know the exact mechanism by which this works,
but I would bet that it's related to the chemical exposure (as the authors
suggest in the Discussion section), i.e. exposure to the scent causes
ingestion of the chemical which then affects the genetic contents of the
gametes. That's really really interesting, but isn't the same as "learned
behavior can be inherited". In this case, it looks like it's sensitivity to
the scent that is inherited, which was confirmed not just via behavioral
methods but by looking at the neurons devoted to it.

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SubiculumCode
I'm going to throw out an off-the-cuff hypothesis. What about microchimerism
as an inheritance process? Microchimerism is the presence of of cells that
originate from another individual and are distinct from the cells of the host.
Transmission between mother fetus has been observed. Moreover, olfactory bulbs
are one area with continued adult neurogenesis. Thinking on that, I reasoned
that if so, there might be increased neurogenesis in the olfactory bulbs
during pregnancy in mice. A quick lit search came up with:
[https://www.ncbi.nlm.nih.gov/m/pubmed/12511652/](https://www.ncbi.nlm.nih.gov/m/pubmed/12511652/)
Yes, increased neurogenesis during pregnancy in response to particular
hormone. Pretty out there hypothesis, I know...

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dgreensp
Note that the “inheritance” can come from the father, and also happens with in
vitro fertilization.

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memebox3v
Well it's also true that you can pick up cells from people you are genetically
similar too and live in close proximity to. This might play a part in group
cohesion?

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everdev
It makes more sense that learned behavior and can be inherited by offspring
rather than random mutations producing complex advantageous behavior but
exciting to hear that it's been replicated.

I wonder if offspring of older parents possess an advantage of possibly having
more learned behavior passed down.

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petermcneeley
Final vindication of Lamarck.

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memebox3v
The Darwinism/Lamarckism thing is wrapped up in politics. Darwinism is used as
a justification of the social order. Might is right. The strong survive.
Lamarckism has a more touchy feely feel to it. Not that Darwinism is
fundamentally wrong! Its just that the nuances are ignored because of the
politics.

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mikekchar
I thinks that's a misinterpretation of Darwinism. The strong don't survive.
The surviving ones survive. That's the whole point. Darwinism isn't an
optimisation algorithm. A set of circumstances that were favourable for
survival with a particular trait may not necessarily be favourable in the
future. At any given point, though, the ones that survived are the ones that
you can see, so it appears as though they were "selected". This theory is
nicer than Lamarckism because it literally needs no mechanism. In order to
accept Lamarckism you need to show that species change due to environmental
pressures. That's more difficult.

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bonesss
> _Darwinism isn 't an optimisation algorithm. A set of circumstances that
> were favourable for survival with a particular trait may not necessarily be
> favourable in the future._

While agreeing with the thrust of your post, personally I think that Darwinism
is a form of optimization, but the mild confusion around Darwinism that you're
describing is a confusion about what that system optimizes _for_.

Darwinism optimizes for survival in the specific environment and circumstance,
and plays out over time. Darwinism does not optimize for "best" or "strongest"
or the "mightiest".

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tritium
I think this also blows apart some nascent theories regarding toxoplasmosis.

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azeotropic
This isn't particularly rigorous. Like all of these studies that claim to
support epigenetic memory in mice, they've started with mixed genetic
background mice, so that none of the offspring are genetically identical to
the parents. You can't rule out the possibility that genetic differences are
responsible for this result.

This is publication bias in action. Studies that don't show epigenetic
inheritance don't get published. Where are all the properly controlled
experiments using inbred strains?

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rkangel
I am far from a geneticist (or in fact any form of scientist), but why do
normal experimental controls not work in the case of this experiment?

You perform the odor exposure to half of your group and not the other half
(the control group). Then you compare the results (measurement of the
offspring) between control group and non-control group.

Assuming that your group size is large enough that the measured difference can
be considered statistically significant, then it doesn't matter what other
variances there are - you have controlled for them.

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hycaria
There are strains of mice which have very little genetic variability, thus
excluding (or at least diminishing) other variations than the studied effect.
This study apparently didn't use one of such strains, so many genes could
interfere. Large enough is otherwise _really_ large.

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Red_Tarsius
Sometimes I wonder what the epigenetic effects of porn will be on the long
run. The illusion of living in a plentiful environment could have unforeseen
consequences over the brain of our children.

