We’ve got transgenerational epigenetic inheritance on the mind and now strangely enough it seems that the mind also causes transgenerational epigenetic inheritance?! Researchers have just shown the strangest case of inheritance yet: soma to germline.
A talented team from the University of Maryland have been tracing double stranded RNA (dsRNA) in C. elegans and have made some interesting observations about the movement of mobile RNA from tissue to tissue and provided some extensive characterization of the transport system. But now it seems that rather than just transmitting a signal from somatic cell to somatic cell via some RNA interference (RNAi), the mobile RNAs can also use their RNAi powers to change the germline for quite some time.
Using a model system involving transgenic GFP worms and providing neuronal dsRNA to target and silence GFP expression via RNAi, the researchers found that:
- The neuronal mobile RNAs can enter a lot of somatic cells and the germline.
- This transfer is achieved by the dsRNA selective importer: SID-1 and some other machinery involving the argonaute family.
- Interestingly, the somatic silencing doesn’t cause inheritance, even with multi-generational exposure.
- But the germline silencing lasts for >25 generations, long after the source of neuronal mobile RNAs is lost.
Ultimately, this appears to be the first shown case of RNAi being transmitted from a somatic cell to the germline and eliciting a persistent inheritance across generations. Senior author Antony Jose says, “Will what happens to my body in a lifetime affect my descendants? People have wondered this for a long time. But, definitive experiments to answer this question have been difficult. This is because our understanding of complex animals, like humans, is incomplete. Even with C. elegans – the best characterized animal in all of biology – we have now uncovered a level of organization that we did not know existed before. Now we need to explore the limits of this discovery and how it might alter our ideas about evolution and behavior. With an open mind, some day we might have a clear answer.”
Go learn how to transmit your brain across generations in PNAS, February 2015