Moshe Szyf presents research linking early-life maternal environment to lasting epigenetic changes. He summarizes rodent studies and mentions parallel observations in humans and monkeys, proposing that positive maternal care increases serotonin signaling in the brain, triggering signaling cascades (phosphorylation events) that recruit transcription factors and chromatin/methylation enzymes to program gene networks (e.g., in the hippocampus).
So we did a series of rodent studies and then we looked at humans and monkeys as well to look at a connection between what happens early in life and perhaps DNA methylation mediating it. So the way we think about it is like this is the maternal environment. Either the positive maternal care result in activating pathways in the brain that respond to that, for example, serotonin that responds to so called reward pathways. And that pathway activates a series of sequence events in critical cells like in the hippocampus, that eventually result in epigenetic programming of a set of genes. Now we know it's not just one gene, but the entire circuitry of genes is methylated differently in response to the maternal care. And so it doesn't sound as magic once you understand that that when there is maternal care, the animal responds with high serotonin, serotonin axon receptors that trigger on what we call signaling pathways, a series of phosphorylations that eventually activate transcription factors that can read addresses in the genome and take to the genome a load of chromatin and methylation modifying enzymes and program the genome.
