“But if you manage to produce RNA by recreating plausible conditions from the time and seeing what results, then sure, you’ve shown that it can happen.”
Is that the type of experiment that leads to the synthesis of RNA? I know they can synthesize RNA with human-managed reactions, but I haven’t seen that they can just supply some soup of amino acids and organic chemicals under the right conditions where the RNA will spontaneously form.
“Depends on what you mean by “sensible,” I guess. By my standards, there are at least a few sensible hypotheses.”
Well, they’ve got hypotheses, but yes I guess sensible is a personal judgement. Ultimately, we will have to see if any of their hypotheses ever make it to the next level, and that will be the final measure of the quality of the 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.Now, I agree that’s a lot of manipulation. But the point is that they weren’t directly assembling RNA or using a process they knew would work. They were trying variations on conditions they though might have obtained on a prebiotic Earth, without knowing for sure what they’d get.
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.”