Can someone give a quick ELI5 into the exact method and rough biological explanation in the study?
From what I understand roughly from the artstechnica layman explanation, the microRNA expression can be influenced by an individual's environment (in the case of the mouse, 36 hours of constant light, a 15-minute exposure to fox odor etc.) These microRNA levels act somehow as regulators/promoters to chromosome molecular structure (basically whether a particular region is wound up tightly or loosely, making that region either harder or more accessible for the DNA transcription machinery), thereby effectively regulating the accessibility and expression of the genes (in this case, genes responsible for "down regulating stress [pathways] of mice") stored in that region.
Although the innate DNA structure (source code) didn't change from parent to offspring, the environment influences (Larmakian inheritance or metaphorically the user-defined environment path) was passed down to the offspring via the microRNA (that was optimized for/influenced by the father's environment) in the father's sperm cells - such that the genes are regulated epigenetically in the child same as the father's from the get-go (e.g., inheriting the environment paths, importing the older browser's bookmarks).
I have several questions, 1) please correct my layman understanding if any of it is off (don't have access to PNAS unfortunately), 2) if someone in the field can explain how microRNA actually regulate the chromosomes and histones, 3) Even if the microRNA is passed down to the offspring, is microRNA expression level in that offspring going to remain persistent? Meaning suppose the offspring is exposed to a totally different environment in contrast to the parent, will the offspring's microRNA eventually change to match its changing environment, i.e., how does microRNA get expressed and regulated in the first place?
Thanks for posting this very interesting paper on Larmakianism making a comeback!