The creationist nightmare scenario came a little closer a couple of days ago when a team of scientists published a paper in the Journal of Nature Chemistry, demonstrating that the three chemical precursors for building the basic components of a cell - RNA, lipids and proteins - can all be built by the same chemical process.
The nightmare scenario for creationists is of course the closure of one of the few remaining gaps in which they arbitrarily sit their favourite god and claim this proves its existence. This transparently circular reasoning and deliberate use of the false dichotomy fallacy is also a major plank in the under cover, pseudoscientific form of creationism, intelligent (sic) design. The belief seems to be that, if they can find something science can't currently explain then the only alternative explanation on offer is that their imaginary invisible friend did it. In normal life this form of argument would be seen as laughingly childish but religion has managed to get away with it for centuries.
For biologists the challenge had been to explain how the three basic components of a 'living' system - information (RNA or a precursor replicator), compartmentalization (containing membranes) and metabolism (entropy management and replication) - all came together when all three appear to be essential and so unlikely to arise separately.
Now that challenge may have been met and creationists' gap has just gotten a lot smaller and looks about to be closed altogether. Basically, the debate was about which came first, how it worked in the absence of the other two. The answer seems to be that none of them did and nor did they arise spontaneously by different mechanisms; they all arose together by the same basic process from the same basic building blocks.
A minimal cell can be thought of as comprising informational, compartment-forming and metabolic subsystems. To imagine the abiotic assembly of such an overall system, however, places great demands on hypothetical prebiotic chemistry. The perceived differences and incompatibilities between these subsystems have led to the widely held assumption that one or other subsystem must have preceded the others. Here we experimentally investigate the validity of this assumption by examining the assembly of various biomolecular building blocks from prebiotically plausible intermediates and one-carbon feedstock molecules. We show that precursors of ribonucleotides, amino acids and lipids can all be derived by the reductive homologation of hydrogen cyanide and some of its derivatives, and thus that all the cellular subsystems could have arisen simultaneously through common chemistry. The key reaction steps are driven by ultraviolet light, use hydrogen sulfide as the reductant and can be accelerated by Cu(I)–Cu(II) photoredox cycling.
Of course, there have been other attempts to explain the origins of the first protocells, including a very plausible mechanism in deep ocean thermal vents, so this explanation is just another plausible mechanism under consideration. Some of these would be extremely difficult to demonstrate for several reasons, the main ones being replicating the special conditions, the time requires (it could have taken a few million years) and the possible low expectancy of success (a one in ten million chance of success, for example). The Earth of course have the first two and a one in ten million chance has a high probability of occurring just once in half a billion years, and it might have only needed that one.
However, this latest suggested mechanism appears to have the advantage of being demonstrable and reproducible - the test of a good scientific hypothesis - so time will tell if this proves to be the case here.
Creationists should start to prepare their disinformation campaign right now if they aren't to have a rude awakening when their nightmare turns out to be more than just the fearful dream of a fraud about to be exposed although why on Earth they should expect their few favourite remaining gaps in science to contain their god when none of the others ever have, is one of the enduring mysteries of religious apologetics.
My thanks to @Ellif_DWulfe for tweeting a link to this.
'via Blog this'