or, my great grandpappy was a lump o’ clay.
Has anyone read the theories of Graham Cairns-Smith? He is a Scottish chemist who proposed that ‘life’ on earth did not in fact begin with carbon-based molecules, it began with inorganic minerals such as clays. Very briefly: Crystalline clays were the first ‘naked replicators’ - they can store heritable information, a basis for genetic evolution. They can also transmit this information and even undergo natural error-correction.
The reason we’re not all made of quartz is that somewhere along the line, a genetic takeover occurred. The clays catalysed the assembly of small organic molecules into larger structures such as RNA, peptides etc which became the dominant lifeform that we evolved from.
His theories strike me as a good example of ideas that are way, way out there but nonetheless rigorously thought through - I’d be interested to hear any real objections to his line of reasoning. I also confess to being blown away by his creativity in coming up with this concept.
The idea that clays can catalyse the synthesis of organic molecules is indisputable, been demonstrated hundreds of times. The Cairns-Smith behaviour of clays in terms of information storage etc also seems to be in line with mainstream inorganic and materials chemistry thinking. What I am not grasping is the link between the two - the genetic takeover. Why not just say that clays can catalyse the assembly of RNA and leave it at that, without invoking the crystalline gene hypothesis?
The page I link to actually answers this point with the ‘booster rocket’ hypothesis, but I’ve not really digested that argument yet. I have just ordered Cairns-Smith’s ‘genetic takeover and the mineral origins of life’ to get the SD on the whole story.
I predict that theories like Cairns-Smith and others are going to be making a bit of a comeback in the next ten years. There was a feeling amongst chemists that the Miller-Ure experiment / RNA catalyst work was basically proof of concept. All that was needed to crack abiogenesis was to demonstrate that you could assemble RNA in the lab under pre-biotic conditions. This has not happened by a long shot, and people are now musing over whether stuff like RNA is a red herring, as it is so complicated a molecule in this context.
Molecular evolution doesn’t have the same political resonance as the evolution of the species, so I guess is a narrower debate. Nonetheless, the person who figures out abiogenesis will be elevated to the level of Einstein. I wonder if that person was Graham Cairns-Smith?