How epigenetic memory is passed through generations: Sperm and eggs transmit memory of gene repression to embryos
September 18, 2014
Excerpt: “There are dozens of potential epigenetic markers. In studies that document parent-to-child epigenetic inheritance, it’s not clear what’s being passed on, and understanding it molecularly is very complicated. We have a specific example of epigenetic memory that is passed on, and we can see it in the microscope. It’s one piece of the puzzle.”
See: Maleszka et al (2013). They link oxidation of 5Mc to 5hmC from the main pathway that removes methyl tags from the genome to brain-increased levels of 5hmC in gene bodies that correlate with active transcription.
Excerpt: “Within the neuronal function-related genes, gain of 5hmC is accompanied by loss of H3K27me3…”
Taken together with what is known about nutrient-dependent pheromone-controlled cell type differentiation via amino acid substitutions in the honeybee and other model organisms, a model of RNA-mediated cause and effect suggests learning and memory of food odors and species-specific pheromones links transgenerational epigenetic inheritance via the molecular mechanisms that transmit a ‘memory of repression,’ which can be linked to behavior.
The link from conserved molecular mechanisms to transgenerational epigenetic inheritance of behavior appears to occur in the context of the systems complexity of nutrient-dependent changes in the microRNA/messenger RNA balance and the overwhelming influence of all epigenetic effects on cell type differentiation in all cells of all individuals of all organisms (i.e., of all genera). It is now clearer that control of cell type differentiation occurs via the combination of epigenetic effects on the development of morphological phenotypes and on the development of behavioral phenotypes during life history transitions via amino acid substitutions that stabilize DNA in organized genomes via nutrient-dependent pheromone-controlled ecological adaptations to nutrient availability. See also: Starvation-Induced Transgenerational Inheritance of Small RNAs in C. elegans