3 ms·

Hello, I don't have access nor the time to grok the full paper. http://www.pnas.org/content/early/2015/10/14/1508347112.full.pdf http://www.pnas.org/content/ear

Hello, I don't have access nor the time to grok the full paper. http://www.pnas.org/content/early/2015/10/14/1508347112.full.pdf http://www.pnas.org/content/early/2015/10/14/1508347112.full... 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!

fjarlq 11y ago
https://en.wikipedia.org/wiki/Transgenerational_epigenetic_inheritance https://en.wikipedia.org/wiki/Transgenerational_epigenetic_i...
milkcircle 11y ago
A quick answer to your question #1/2: microRNA (miRNA) is the substrate of a very complex piece of cell machinery that uses the miRNA sequence to find complementary messenger RNA (mRNA). When miRNA binds to its respective mRNA, the machinery (whose details I will not go into) degrades the mRNA, preventing its translation into protein. So while the DNA remains unaltered by the miRNA, protein expression is regulated on the level of mRNA degradation. MiRNA and short-hairpin RNA are tremendously useful in the laboratory setting to knock down the expression of genes without having to do gene modifications. This paper shows that miRNA can be passed from father to child through the sperm, and this miRNA can affect the way certain genes are expressed. As for your question #3, I couldn't find any information in the paper regarding how long the miRNA persisted in the offspring. The miRNAs seem to have a long-term effect on genes in the paraventricular nucleus of the hypothalamus, but whether this is due to effects of miRNA solely in the development of the zygote, or whether the miRNA in the adult is also important, is unclear. It seems likely that changes due to the miRNA in fetal development alone could be sufficient in dramatically changing stress responsitivity, but this remains to be proven. In another famous study, maternal nurture plays a very important role in the epigenetic development of baby mice [1]. So it could very well be that a favorable and nurturing environment may cause epigenetic changes in the offspring that might counteract the actions of the miRNA described here. Again, this is something that the paper does not show and therefore we can only speculate at this point. Hope this helps! [1] http://www.nature.com/neuro/journal/v7/n8/full/nn1276.html http://www.nature.com/neuro/journal/v7/n8/full/nn1276.html
- noname123 11y ago
  Thank you milkcircle for your detailed and precise answers for my specific questions! And also going beyond to bring up another paper following up on nurture in terms influences epigenetic development of offsprings. Thanks for clearing up my confusion on how miRNA works ("regulate[s] on the level of mRNA degradation"). I learn something new today thanks to you!

fjarlq 11y ago

https://en.wikipedia.org/wiki/Transgenerational_epigenetic_inheritance https://en.wikipedia.org/wiki/Transgenerational_epigenetic_i...

milkcircle 11y ago

A quick answer to your question #1/2: microRNA (miRNA) is the substrate of a very complex piece of cell machinery that uses the miRNA sequence to find complementary messenger RNA (mRNA). When miRNA binds to its respective mRNA, the machinery (whose details I will not go into) degrades the mRNA, preventing its translation into protein. So while the DNA remains unaltered by the miRNA, protein expression is regulated on the level of mRNA degradation. MiRNA and short-hairpin RNA are tremendously useful in the laboratory setting to knock down the expression of genes without having to do gene modifications. This paper shows that miRNA can be passed from father to child through the sperm, and this miRNA can affect the way certain genes are expressed. As for your question #3, I couldn't find any information in the paper regarding how long the miRNA persisted in the offspring. The miRNAs seem to have a long-term effect on genes in the paraventricular nucleus of the hypothalamus, but whether this is due to effects of miRNA solely in the development of the zygote, or whether the miRNA in the adult is also important, is unclear. It seems likely that changes due to the miRNA in fetal development alone could be sufficient in dramatically changing stress responsitivity, but this remains to be proven. In another famous study, maternal nurture plays a very important role in the epigenetic development of baby mice [1]. So it could very well be that a favorable and nurturing environment may cause epigenetic changes in the offspring that might counteract the actions of the miRNA described here. Again, this is something that the paper does not show and therefore we can only speculate at this point. Hope this helps! [1] http://www.nature.com/neuro/journal/v7/n8/full/nn1276.html http://www.nature.com/neuro/journal/v7/n8/full/nn1276.html

noname123 11y ago
Thank you milkcircle for your detailed and precise answers for my specific questions! And also going beyond to bring up another paper following up on nurture in terms influences epigenetic development of offsprings. Thanks for clearing up my confusion on how miRNA works ("regulate[s] on the level of mRNA degradation"). I learn something new today thanks to you!