In today’s eco-devo class, we’re going to be talking about a general phenomenon: the physical reality of your feelings, as witnessed by changes in gene expression. Seems appropriate for Valentine’s Day, right? On Monday I lectured on a few principles of gene regulation, and how environmental factors are transduced into patterns of epigenetic activity. Today, the students are going to answer questions and give explanations on the mechanics of all that, and then on Friday, they’ll discuss this paper: “Maternal care as a model for experience-dependent chromatin plasticity?” by Meaney and Szyf. Here’s part of true love:
The students are going to explain it all to me later this week, so I don’t want to spill all the beans, but in short, these are the results of studies in mice. Happy baby mice are licked and groomed by their mothers, while less happy mice are neglected and stressed. Being groomed increased serotonin levels, which activates adenylate cyclase, which increases cytoplasmic cyclic AMP levels, which activates a serine-threonine kinase called PKA, which activates a DNA binding protein that demethylates specific DNA sequences. Some of these sequences regulate stress responses in the hypothalamic-pituitary-adrenal axis, so those loving mommy-snuggles are changing how baby mice respond to stressful situations, and those responses persist long into adulthood.
So maternal care, or lack of care, is drilling right down to the structure of DNA and making lifelong modifications to your feelings. At least, if you’re a mouse, and humans almost certainly have the same biochemical arrangement. And a scientist can rip out some of your DNA and find a different pattern of epigenetic marks in individuals who had a loving relationship with Mom versus those who were neglected. It’s written in your semi-permanent epigenetic record.
Of course, this is just one pathway, and there are multiple regulatory pathways modulating stress responses, so all is not lost if you have one bad mother. These individual effects are sort of permanent, though, and would require alternative compensatory mechanisms to be overcome. Also, keep in mind that bad mothers could be a product of bad grandmothers, and that these epigenetic modifications can ripple across multiple generations.
Indeed, maternal effects could result in the transmission of adaptive responses across generations. In humans, such effects might contribute to the familial transmission of risk and resilience. Finally, it is interesting to consider the possibility that epigenetic changes could be an intermediate process that imprints dynamic environmental experiences on the fixed genome, resulting in stable alterations in phenotype – a process of environment-dependent chromatin plasticity.
I hope you all have an opportunity to stimulate some environment-dependent chromatin plasticity today. If you don’t have a date, you can at least call your mom, or be kind to a child. Modify someone’s DNA with a hug!
OT
Valentine’s Day: I love this news item.
In some countries, acts have consequences…
What? Shadenfreude can be as intense as love!
(OK , I am leaving now)
Ex-French President Sarkozy handed one-year jail sentence for illegal campaign financing – Raw Story
https://www.rawstory.com/ex-french-president-sarkozy-handed-one-year-jail-sentence-for-illegal-campaign-finance/
On its face I would assume the mouse maternal grooming model too dichotomous, but useful as a first pass.
Several years ago I kinda hate-read Susan Cain’s pop-psych book Quiet. It extolled the virtues of introverts as square pegs in the round holes of our Dale Carnegie induced extraverted hellscape. Ok, I said, but what about transcending the Jungian forced dichotomy and recognizing the ambiverts. Who recognizes them?
An upside of Cain’s tedious book was introduction to the orchid hypothesis of childhood psychological development (its own troubling dichotomy contrasting orchid and dandelion kids). The maternal care dichotomy PZ reductively highlights via some signal transduction scheme runs up against variation in children per resilience (dandelions) or sensitivity (orchids). Orchids can be most vulnerable to neglect but flourish well beyond dandelions in the right supportive environment:
https://www.theatlantic.com/magazine/archive/2009/12/the-science-of-success/307761/
I was and am skeptical of such a scheme, but it does complexify the developmental situation a bit and doesn’t doom kids who possess a gene variant to a bad outcome.
But alas the schema is complexified even more but a subgrouping of intermediates called tulips, where personality traits of neuroticism and extraversion are important to where one falls amongst the three flowers:
https://www.nature.com/articles/s41398-017-0090-6
So I guess people (psychologists) are taking this flower-child metaphor seriously still. Jung’s personality defining dichotomy of extraversion-introversion lives on in the human garden. Wasn’t neuroticism a focus of Freud’s?
Reminds me of this comic.
I dunno if it can be reduced entirely to bad vs good parenting. Some situations are outside the control of parents and grandparents by extension. Given cycles of poverty exacerbated by racism, one can wonder how impoverished upbringings can result in negative epigenetic imprinting that carries across generations. There might be some child neglect by the parents, perhaps an economically forced situation, but societal neglect added to that. Some kids may be more resilient than others. Reading Viola Davis’s biography has made me reflect a bit on such things.
Florida has eliminated sociology as a core requirement.
Ah, Valentine’s Day. The most miserable day of the year.
Floriduh has eliminated humanity as as a requirement for being human.
“Some kids may be more resilient than others”
Which is why the tired conservative argument “Lincoln had it bad, too, and he overcame it” is bogus.
And evolution will favor a wide spread of personalities (to the extent that personality is guided by genetics).
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“Florida has eliminated sociology as a core requirement”
I will make a wild guess and blame it on semi-literate politicians who think it is associated with ‘socialism’. Like Turkey during the military rule, where a shipment of sociology textbooks was impounded by customs and burned as suspected communist literature.
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Also, things not directly useful for for-profit activities are a liberal luxury that taxpayers should not pay for.
@7 I think Floriduh is long over the “semi literate politician ” phase
brigerjoohansson @ #7 — “…a wild guess and blame it on semi-literate politicians who think it is associated with ‘socialism’.” I would assume there is some of that, but also some politicians see sociology as part of the academic critique of American society, “Critical Race Theory” and so forth. Those invested in American (aka “White”) exceptionalism don’t want any examination of their assumptions or the impact on lives of those assumptions.
@8 , semi literate? Like an orangutan 🦧 literate? But orangutans are smarter and have better personalities than conservative politicians
“Some kids msy be more resilient than others”
As mentioned before, evolution may tend to provide a wide set of personalities.
It has been suggested that “pro-social psychopaths”, people that were well treated as children and have retained their ability for empathy, remorse etc. have some advantages over others in that they may not be as devastated as others during bad times (it is more complicated than that, but this is the Readers Digest version).
Psychopats with a non-optimal childhood on the other hand tend to grow up to be, er, psychopaths.
On the other side of the spectrum are what what psychologists in Sweden called ‘dandelion children’ who thrive despite a quite bad start.
-Considering how badly Thump Dubya et al have messed up where US kids grow up, I wish there was some pharmaceutical fix to environment-dependent chromatin plasticity so you get out of this negative loop.
I know bugger all about child psychology but constant insecurity must be bad.