Salk Scientists Discover RNA’s Role in Early Evolution
Groundbreaking research conducted by the Salk Institute has revealed new insights into the origins of life and the potential role of RNA in early evolution. The study, published in Proceedings of the National Academy of Sciences (PNAS) on March 4, 2024, unveils an RNA enzyme capable of accurately replicating functional RNA strands while also allowing new variations to emerge over time. These findings provide substantial evidence supporting the RNA World hypothesis and move researchers closer to producing autonomous RNA-based life in the laboratory.
The RNA World hypothesis, first proposed in the 1960s by scientists such as Salk Fellow Leslie Orgel, suggests that life began with an era dominated by small RNA molecules. These stringy RNA molecules are believed to have established the dynamics of Darwinian evolution even before cells, proteins, and DNA existed. This new research brings us closer to understanding how this RNA world may have functioned.
The research team, led by Salk President Gerald Joyce, has been exploring the capability of RNA polymerase ribozymes to replicate RNA strands. Over the past decade, they have used directed evolution to develop new versions of these ribozymes that can replicate larger molecules. However, most of these versions have had a crucial flaw—they were unable to copy sequences accurately enough, resulting in generations of RNA strands that no longer resembled the original sequence and lost their function.
In a groundbreaking development, the latest RNA polymerase ribozyme developed in the lab demonstrated significantly higher accuracy in replicating RNA strands. The researchers were astonished to find that not only did the ribozyme accurately replicate functional RNA strands, but new variations also emerged over time. These new variants, performing similarly to the original strands, were easier to replicate, which increased their evolutionary fitness and eventually led them to dominate the population.
These findings shed light on the crucial role of replication fidelity in facilitating evolution
