There is a Gordon Research Conference dedicated to the Origins of Life. Without a doubt, this is the most eclectic gathering of some of the oddest people in the science community. I have always wanted to attend one, but never had a chance. I can only imagine the types of heated discussions that go on there. The trouble with this branch of science is that we will, of course, never be able to run control experiments to prove or disprove any hypothesis. Thus, ideas about how life emerged are relegated to conjectures. But people keep trying and I really enjoy reading about attempts to explain how some of the primordial forms of life might have emerged.
Replication and molecular evolution using trivial (pre-RNA and pre-DNA) molecules has been shown in models, but never convincingly enough. We don’t even need to go as far as replication: thinking about how peptide bonds might have been created in water is tough enough! This allows me to bring up a curious paper by Ghadiri and co-workers, published in Astrobiology (this is not something I read all the time…). In it, the authors make a suggestion that carbon disulfide (CS2) might have acted as the coupling agent. I like this idea and I think the experiments are convincing, especially the fact that this peptide bond formation works in water. Besides COS, CS2 is certainly one of the cheapest and most readily available coupling agents, which might have been in abundance when all those sparks were flying on earth several billion of years ago.