Nature: Lab-made primordial soup yields RNA bases

Carell, an organic chemist, and his collaborators have now demonstrated a chemical pathway that — in principle — could have made A, U, C and G (adenine, uracil, cytosine and guanine, respectively) from basic ingredients such as water and nitrogen under conditions that would have been plausible on the early Earth. The reactions produce so much of these nucleobases that, millennium after millennium, they could have accumulated in thick crusts, Carell says. His team describes the results in Science on 3 October1.

The results add credence to the ‘RNA world’ hypothesis, says Carell, who is at the Ludwig Maximilian University of Munich in Germany. This idea suggests that life arose from self-replicating, RNA-based genes — and that only later did organisms develop the ability to store genetic information in the molecule’s close relative, DNA. The chemistry is also a “strong indication” that the appearance of RNA-based life was not an exceedingly lucky event, but one that is likely to happen on many other planets, he adds.

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Now scientists have created something in the lab that is tantalizingly close to what might have happened. It's not life, they stress, but it certainly gives the science community a whole new data set to chew on.

The researchers, at the Scripps Research Institute, created molecules that self-replicate and even evolve and compete to win or lose. If that sounds exactly like life, read on to learn the controversial and thin distinction....

f RNA is in fact the ancestor to DNA, then scientists have figured they could get RNA to replicate itself in a lab without the help of any proteins or other cellular machinery. Easy to say, hard to do.

But that's exactly what the Scripps researchers did. Then things went surprisingly further.

'Immortalized'

Specifically, the researchers synthesized RNA enzymes that can replicate themselves without the help of any proteins or other cellular components, and the process proceeds indefinitely. "Immortalized" RNA, they call it, at least within the limited conditions of a laboratory.

More significantly, the scientists then mixed different RNA enzymes that had replicated, along with some of the raw material they were working with, and let them compete in what's sure to be the next big hit: "Survivor: Test Tube."

Remarkably, they bred.

And now and then, one of these survivors would screw up, binding with some other bit of raw material it hadn't been using. Hmm. That's exactly what life forms do ...

When these mutations occurred, "the resulting recombinant enzymes also were capable of sustained replication, with the most fit replicators growing in number to dominate the mixture," the scientists report.

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