We have abiogenesis…sort of .They’ve been trying to synthesize ribonuleotides for a long time without success. Looks like they’ve finally kicked it in the nuts:
While reactions to make RNA from ancient precursors worked on paper, the chemistry didn’t work in the lab. And some scientists thought even RNA molecules were too complex to have spontaneously formed in the primordial soup. Sutherland and his colleagues have shown the reactions are possible.
RNA molecules are formed from three components: a sugar, a base and a phosphate group. In past research, chemists developed each of the components and then tried to put them together to make the complete molecule. “But the components are quite stable, and so they wouldn’t stick together,” Sutherland says. “After 40 years of trying, we decided there had to be a better way of doing this reaction.”
The team took a different approach, starting with a common precursor molecule that had a bit of the sugar and the base. “Basically, we took half a base, added that to half a sugar, added the other piece of base, and so on,” Sutherland says. “The key turned out to be the order that the ingredients are added and the way you put them together — like making a soufflé.”
Another difference is that Sutherland and his team added the phosphate to the mix earlier than in past experiments. Having the phosphate around so early helped the later stages of the reaction happen more quickly and efficiently, the scientists say.
I found this piece in Wired very helpful in giving me a decent picture of what they’re talking about in a real world hypothesis:
They mixed the molecules in water, heated the solution, then allowed it to evaporate, leaving behind a residue of hybrid, half-sugar, half-nucleobase molecules. To this residue they again added water, heated it, allowed it evaporate, and then irradiated it.
At each stage of the cycle, the resulting molecules were more complex. At the final stage, Sutherland’s team added phosphate. “Remarkably, it transformed into the ribonucleotide!” said Sutherland.
According to Sutherland, these laboratory conditions resembled those of the life-originating “warm little pond” hypothesized by Charles Darwin if the pond “evaporated, got heated, and then it rained and the sun shone.”
Such conditions are plausible, and Szostak imagined the ongoing cycle of evaporation, heating and condensation providing “a kind of organic snow which could accumulate as a reservoir of material ready for the next step in RNA synthesis.”
Intriguingly, the precursor molecules used by Sutherland’s team have been identified in interstellar dust clouds and on meteorites.
It’s all very cool. I especially like that Darwin might have called it correctly after all when he wrote to a friend that life probably started in some “…warm little pond with all sorts of ammonia and phosphoric salts.”