(ORDO NEWS) — Researchers at the University of Tokyo have created an RNA molecule that can not only replicate, but also “evolve” into a variety of more complex molecules. The new find could close a big gap in the mystery of how life began on Earth.
How exactly life arose from inanimate matter is one of the most serious mysteries for modern science. It has long been assumed that RNA acted as a kind of precursor to DNA – if these simple molecules existed in the “primordial soup” of the early Earth, they could begin to self-replicate and diversify into various forms.
As molecules became more complex, they could eventually give rise to cells with DNA molecules that gave rise to all the life forms we see today.
As elegant as this explanation was, it remained unknown whether RNA molecules could actually undergo this kind of evolution. For a new study of this issue, Tokyo scientists conducted a long-term experiment on RNA replication.
The team incubated RNA replicase molecules in oil-immersed water drops at 37°C for five hours at a time. Nutrients were then added to the mixture, diluting the solution to one-fifth of the original concentration, and stirred before being allowed to incubate for another five hours.
This process was repeated for 240 cycles, for a total of 1200 hours of the experiment – so scientists tried to partially mimic the conditions of the primordial broth.
Indeed, RNA molecules have mutated and diversified over time . The single original “species” eventually branched out into five different lineages, whose population fluctuated before stabilizing.
A network of interactions developed between the various bloodlines – most intriguingly, a collaboration that helped them reproduce more efficiently.
What does this discovery mean for world science
“To be honest, we initially doubted that such different RNAs could evolve and be in the same territory,” said Ryo Mizuuchi, author of the study. “In evolutionary biology, the ‘principle of competitive exclusion’ states that more than one species cannot coexist if they compete for the same resources.
This means that the molecules must establish a way of using different resources for each of its varieties for sustainable diversity. However, these are just molecules, so we wondered if non-living chemical species could spontaneously ‘develop’ such innovations.”
While the experiment shows that RNA could have evolved on its own and led to complex life, such a scenario is not necessarily the case in the real world. The team plans to conduct further experiments to uncover in more detail how RNA could pave the way for living systems.
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