In origin-of-life experiment, cooperative molecules win out

A schematic of the ribozyme in question (the Azoarcus group I intron), showing the sites where it can be broken into pieces.

NIH

Origin-of-life researchers have made great progress in creating RNA molecules with interesting biochemical activities, but they haven't yet managed to create a molecule that can fully replicate itself, an item that's considered to be the critical step that could get evolution, and thus life itself, started. But a paper published in this week's edition of Nature suggests we may be thinking about things a bit wrong. They show that it's possible to have a population of distinct RNAs that can cooperate to catalyze reactions that expand the population. And, if you mix them together, the cooperative molecules will outcompete any selfish replicators.

In a way, the difference between thinking in terms of individuals and populations mirrors a debate that has gone on for decades in the evolutionary biology community. At some levels, you can think of evolution in terms of individuals competing against their peers, and each new mutation will probably start out in a single individual. But, to have an appreciable impact, that mutation will have to spread within a population. It's also possible for populations to undergo evolutionary selection as a group, as they cooperate to compete against other groups from the same or different species.

Now, it looks like arguments over individual vs. group selection may extend to the molecular realm.

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