They discover RNA capabilities that allow the evolution of life on a molecular scale

According to the naturalist Charles Darwin, evolution was “descendants with modifications”, that is, genetic information in the form of sequences of DNA which is transmitted from one generation to the next, but with slight variations that allow new traits to be introduced into a population.

In the 1960s, some scientists, including Leslie Orgel of the Salk Institute, proposed that the origin of evolution was “world of RNA” and that these small molecules were those that governed the primitive Earth and those that, over time, established the dynamics of the evolution of species.

Now, new research from the Salk Institute, published this Monday in the journal Proceedings of the National Academy of Sciences (PNAS), provides new information about the origins of life and presents evidence that supports the hypothesis of “RNA world”.

The research has uncovered the capabilities of RNA that make evolution possible at the molecular scale, while bringing scientists closer to producing autonomous RNA life in laboratories.

RNA, precursor of life?

For years, Joyce and other scientists have been exploring the idea that RNA could be the precursor to life. To do this, they study RNA polymerase ribozymes, RNA molecules that can make copies of other RNA strands.

Over the past decade, Joyce and his team have been developing RNA polymerase ribozymes in the lab to produce new versions of evolution capable of replicating larger molecules. But most are unable to copy the sequences with sufficient precision.

Therefore, after many generations, the resulting RNA strands have so many errors that they look nothing like the original and have completely lost their function. Until now.

The latest RNA polymerase ribozyme developed in the lab includes a series of crucial mutations that allow it to copy a strand of RNA with much greater precision.

In these experiments, the RNA strand that is copied is a “Hammer head” (a small molecule that cuts other RNA molecules into pieces).

The team discovered that not only did the RNA polymerase ribozyme accurately replicate functional hammerheads, but over time, new variations of hammerheads emerged that functioned similarly, but whose mutations made them easier to replicate, making them easier to replicate. which increased their evolutionary fitness and led them to finally dominate the hammerhead population in the laboratory.

“This study suggests that the dawn of evolution could have been very early and very simple. “Something at the level of individual molecules could sustain Darwinian evolution, and have been the spark that allowed life to become more complex, moving from molecules to cells and multicellular organisms.”details Nikolaos Papastavrou, associate researcher in Joyce’s laboratory and first author of the study.

“We pursue the dawn of evolution. By revealing these novel capabilities of RNA, we are uncovering the possible origins of life itself, and how simple molecules could have paved the way for the complexity and diversity of life we ​​see today.”explains Gerald Joyce, lead author of the study and president of Salk.

Joyce’s team is now recreating this process in laboratory test tubes to produce better-performing polymerase that can replicate itself, which would be the origin of autonomous RNA life in the laboratory, something that, according to the researchers, could be achieved in the next decade.