Studies published within the last year have suggested that trauma on Holocaust survivors have influenced the likelihood of stress disorders and genes in their children– this hypothesis is called “epigenetic inheritance,” the process by which environmental stress can affect the genes of future generations. Scientists at American Friends of Tel Aviv University sought out to find the underlying genetic mechanisms as to how genes could be passed on, and the answer may be due to small RNAs which regulate in gene expression.
Image of Holocaust survivors showing tattooed prison number
Until now, it has been assumed that a passive dilution or decay governs the inheritance of epigenetic responses,” head researcher Dr. Rechavi, said. “But we showed that there is an active process that regulates epigenetic inheritance down through generations.”– Science Daily
To study this inheritance, researchers exposed worms (C. elegans) to starvation and viruses, sequenced their DNA, then sequenced the DNA of their children to see if there were any inheritance patterns with the aid of computational techniques. In this experiment, they found that there were enzymes, RdRPs, which code for small RNAs to persist in new generations if environmental stress stays the same.
These small RNAs helped prepare their offspring for similar hardships,” Dr. Rechavi said. — Science Daily
In a second experiment, the scientists exposed worms with small RNAs that “silenced” green fluorescent protein (GFP)– which induces a glow within worms. They were able to identify a group of genes that reacted the small RNAs as a way to turn the GFP genes back on and off. They named the group of genes Modified Transgenerational Epigenetic Kinetics (MOTEK) genes– which they think are capable of “turning on or off epigenetic transmission” between generations.
Not only is this study interesting because it shows that DNA has the ability to learn and pass on information about the environment, but even in social context this highlights important moral discussions about Holocaust survivors, or even African-American slaves that we had here in America less than 200 years ago. Will we ever be able to dodge the emotional turmoil of past mistakes or is it engraved in our “DNA memory” ?
- Leah Houri-Ze’evi, Yael Korem, Hila Sheftel, Lior Faigenbloom, Itai Antoine Toker, Yael Dagan, Lama Awad, Luba Degani, Uri Alon, Oded Rechavi. A Tunable Mechanism Determines the Duration of the Transgenerational Small RNA Inheritance in C. elegans. Cell, 2016; 165 (1): 88 DOI: 10.1016/j.cell.2016.02.057
