Dr. Rechavi and his team had previously identified a “small RNA inheritance” mechanism through which RNA molecules produced a response to the needs of specific cells and how they were regulated between generations.
“We previously showed that worms inherited small RNAs following the starvation and viral infections of their parents. These small RNAs helped prepare their offspring for similar hardships,” Dr. Rechavi said. “We also identified a mechanism that amplified heritable small RNAs across generations, so the response was not diluted. We found that enzymes called RdRPs are required for re-creating new small RNAs to keep the response going in subsequent generations.”
Most inheritable epigenetic responses in C.elegans worms were found to persist for only a few generations. This created the assumption that epigenetic effects simply “petered out” over time, through a process of dilution or decay.
“But this assumption ignored the possibility that this process doesn’t simply die out but is regulated instead,” said Dr. Rechavi, who in this study treated C.elegans worms with small RNAs that target the GFP (green fluorescent protein), a reporter gene commonly used in experiments. “By following heritable small RNAs that regulated GFP — that ‘silenced’ its expression — we revealed an active, tuneable inheritance mechanism that can be turned ‘on’ or ‘off.'”
The scientists discovered that specific genes, which they named “MOTEK” (Modified Transgenerational Epigenetic Kinetics), were involved in turning on and off epigenetic transmissions. More. Paper. (paywall)
If this holds up, it will be a valuable contribution. A mechanism for epigenetics is critical. As Michael Behe asks, How, exactly? Not How, according to the Great Man’s Theory, but how exactly does the system work, step by step?
There are so many epigenetic theses out there now that means of testing them become critical.
See also: Epigenetic change: Lamarck, wake up, you’re wanted in the conference room!
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