Epigenetics is fascinating, even bizarre by conventional thought. Some worry that it’s another variety of determinism, just not located in the genes. I have other worries, if not that particular one.
How epigenetics work is that a gene gets switched on or off. The key point is that it’s not permanently set. Some later incident, conditions, behavior, or whatever can switch it back the other way again. Genes in your body are switched on and off throughout your lifetime. But presumably if no significant changes occur in one’s life some epigenetic expressions remain permanently set for your entire life.
Where it gets fascinating is that it’s been proven that epigenetics gets passed on across multiple generations and no one is certain how many generations. In mice, it can extend at least upwards of 7 generations or so, as I recall. Humans, of course, haven’t been studied for that many generations. But present evidence indicates it operates similarly in humans.
Potentially, all of the major tragedies in modern history (violence of colonialism all around the world, major famines in places like Ireland and China, genocides in places like the United States and Rwanda, international conflicts like the world wars, etc), all of that is within the range of epigenetis. It’s been shown that famine, for example, switches genes for a few generations that causes increased fat retention and in the modern world that means higher obesity rates.
I’m not sure what is the precise mechanism that causes genes to switch on and off (e.g., precisely how does starvation get imprinted on biology and become set that way for multiple generations). All I know is it has to do with the proteins that encase the DNA. The main interest is that, once we do understand the mechanism, we will be able to control the process. This might be a way of preventing or managing numerous physical and psychiatric health conditions. So, it really will mean the opposite of determinism.
This research reminds me of other scientific and anecdotal evidence. Consider the recipients of organ transplants, blood and bone marrow transfusions, and microbiome transference. This involves the exchange of cells from one body to another. The results have shown changes in mood, behavior, biological functioning, etc
For example, introducing a new microbiome can make a skinny rodent fat or a fat rodent skinny. But also observed are shifts in fairly specific memories, such as an organ transplant recipient craving something the organ donor craved. Furthermore, research has shown that genetics can jump from the introduced cells to the already present cells, which is how a baby can potentially end up with the cells of two fathers if a previous pregnancy was by a different father, and actually it’s rather common for people to have multiple DNAs in their body.
It intuitively makes sense that epigenetics would be behind memory. It’s easy to argue that there is no other function in the body that has this kind and degree of capacity. And that possibility would blow up our ideas of the human mind. In that case, some element of memories would get passed on multiple generations, explaining certain similarities seen in families and larger populations with shared epigenetic backgrounds.
This gives new meaning to the theories of both the embodied mind and the extended mind. There might also having some interesting implications for the bundle theory of mind. I wonder too about something like enactivism which is about the human mind’s relation to the world. Of course, there are obvious connections of this specific research with neurological plasticity and of epigenetics more generally with intergenerational trauma.
So, it wouldn’t only be the symptoms of trauma or else the benefits of privilege (or whatever other conditions that shape individuals, generational cohorts, and sub-populations) being inherited but some of the memory itself. This puts bodily memory in a much larger context, maybe even something along the lines of Jungian thought, in terms of collective memory and archetypes (depending on how long-lasting some epigenetic effects might be). Also, much of what people think of as cultural, ethnic, and racial differences might simply be epigenetics. This would puncture an even larger hole in genetic determinism and race realism. Unlike genetics, epigenetics can be changed.
Our understanding of so much is going to be completely altered. What once seemed crazy or unthinkable will become the new dominant paradigm. This is both promising and scary. Imagine what authoritarian governments could do with this scientific knowledge. The Nazis could only dream of creating a superman. But between genetic engineering and epigenetic manipulations, the possibilities are wide open. And right now, we have no clue what we are doing. The early experimentation, specifically research done covertly, is going to be of the mad scientist variety.
These interesting times are going to get way more interesting.
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Could Memory Traces Exist in Cell Bodies?
by Susan Cosier
The finding is surprising because it suggests that a nerve cell body “knows” how many synapses it is supposed to form, meaning it is encoding a crucial part of memory. The researchers also ran a similar experiment on live sea slugs, in which they found that a long-term memory could be totally erased (as gauged by its synapses being destroyed) and then re-formed with only a small reminder stimulus—again suggesting that some information was being stored in a neuron’s body.
Synapses may be like a concert pianist’s fingers, explains principal investigator David Glanzman, a neurologist at U.C.L.A. Even if Chopin did not have his fingers, he would still know how to play his sonatas. “This is a radical idea, and I don’t deny it: memory really isn’t stored in synapses,” Glanzman says.
Other memory experts are intrigued by the findings but cautious about interpreting the results. Even if neurons retain information about how many synapses to form, it is unclear how the cells could know where to put the synapses or how strong they should be—which are crucial components of memory storage. Yet the work indeed suggests that synapses might not be set in stone as they encode memory: they may wither and re-form as a memory waxes and wanes. “The results are really just kind of surprising,” says Todd Sacktor, a neurologist at SUNY Downstate Medical Center. “It has always been this assumption that it’s the same synapses that are storing the memory,” he says. “And the essence of what [Glanzman] is saying is that it’s far more dynamic.”
Glanzman’s experiments—funded by the National Institutes of Health and the National Science Foundation—involved giving mild electrical shocks to the marine snail Aplysia californica. Shocked snails learn to withdraw their delicate siphons and gills for nearly a minute as a defense when they subsequently receive a weak touch; snails that have not been shocked withdraw only briefly.
The researchers extracted RNA from the nervous systems of snails that had been shocked and injected the material into unshocked snails. RNA’s primary role is to serve as a messenger inside cells, carrying protein-making instructions from its cousin DNA. But when this RNA was injected, these naive snails withdrew their siphons for extended periods of time after a soft touch. Control snails that received injections of RNA from snails that had not received shocks did not withdraw their siphons for as long.
“It’s as if we transferred a memory,” Glanzman said.
Glanzman’s group went further, showing that Aplysia sensory neurons in Petri dishes were more excitable, as they tend to be after being shocked, if they were exposed to RNA from shocked snails. Exposure to RNA from snails that had never been shocked did not cause the cells to become more excitable.
The results, said Glanzman, suggest that memories may be stored within the nucleus of neurons, where RNA is synthesized and can act on DNA to turn genes on and off. He said he thought memory storage involved these epigenetic changes—changes in the activity of genes and not in the DNA sequences that make up those genes—that are mediated by RNA.
This view challenges the widely held notion that memories are stored by enhancing synaptic connections between neurons. Rather, Glanzman sees synaptic changes that occur during memory formation as flowing from the information that the RNA is carrying.