It all started with an unpretentious conversation in the back of the bus on the way to a meeting for young researchers at Tel Aviv University in Israel. Neurobiologist Oded Rechavi happened to be sitting next to Noam Mizrahi, an expert on Biblical texts and a student of the famous Dead Sea Scrolls.
“Until then, I was never interested in Bible manuscripts, I didn’t know anything about them,” says Rechavi. However, a few minutes of conversation was enough to develop an unconventional plan for analyzing these texts, which is vital to an understanding of Judaism at the time of Christ.
Finally, Rechavi researches the various transmission routes for genetic information. “The manuscripts were made from animal skins. Leather contains DNA. What if it was possible to use the DNA of these animals to classify the texts? ”Asked the couple.
It took seven years – a suitably Biblical number – to get the answers, but the balcony provided Rechavi, Mizrahi, and their colleagues with one of the most original analyzes ever made of Dead Sea documents.
The genetic material of the lambs and calves whose skins were used to make the scrolls helped to show, among other things, that the manuscripts are not only from a small sectarian group in the desert, but come from different regions of ancient Judea and are relatively broader Mode.
“It was a great experience and we would like to do more projects like this in the future,” says Rechavi.
However, the main interest of the Israeli researcher is even more unusual (and potentially revolutionary). When examining the tiny C. elegans worm, which measures only 1 mm, he and his colleagues find that the worm’s life experiences produce genetic information that is not written into the DNA but can still be passed on from generation to generation.
The Tel Aviv scientist will cover the surprising story of these discoveries in a course on the frontiers of biology for young Brazilian scientists, offered by the Serrapilheira Institute in collaboration with the ICTP-SAIFR (International Center for Theoretical Physics-South American Institute of Fundamental Research ) is organized, with English abbreviation).
“I want to talk about the history of genetic inheritance studies and how various patterns have repeated themselves over time, particularly the taboo on this possibility of lifelong inheritance,” he says.
For decades it was believed that only DNA was able to store genetic information that would be passed on from parents to children. This “library” stored in the genome would not be directly affected by what happens in everyone’s life, except in unplanned ways, such as exposure to radiation or chemical substances that can cause random changes in DNA.
However, several recent studies have shown that changes in the instructions for building the organism can result from other biochemical mechanisms, even when the DNA is unchanged. And most fascinatingly, such changes would be a direct response to events in the environment – food shortages, for example, could lead parents to father children with an organism that uses less energy.
Rechavi and his colleagues identified one of the most sophisticated mechanisms of this kind in C. elegans worms. The animal’s neurons produce small RNA molecules (the “raw substance” of DNA) that are passed on to their offspring and help to activate the and modulate deactivation patterns of DNA segments without directly touching them.
“We don’t know exactly what natural stimulus this creates, but the fact is that changes in the production of these small RNAs can, for example, change the way the worms forage for food, and this can be sustained for several generations “explains the scientist.
The process is completely different from what usually happens in the traditional scenario of adapting a species to a specific environment. Usually, DNA mutations that occur randomly undergo natural selection, that is, individuals whose genetic traits allow them to better adapt to the environment reproduce more than others, so their traits in this species become more common over time.
The mechanism elucidated by the Israeli team would therefore make it possible to open an adaptive “shortcut” through the direct influence of the environment itself. It remains to be seen whether it could affect other animal species, such as humans and other mammals, and to what extent it could affect the long-term evolution of C. elegans and other living things.
“These are open questions. We know that small RNAs are present in mammalian sperm, for example, but it is not clear how long their effects last, ”he muses.