I'm starting to feel my age. The I first became aware of Cairns-Smiths writings about the possibility of clay being a template for the formation of life I was actively engaged with clays and soil science. Though not looking at them as the source of life itself. And now I find that 50 years have elapsed before I've gotten around to finding out more about his ideas. The truth is, that they never seemed to catch on though I personally think he was onto something. I remember one of the scientists in our own CSIRO Lab had produced a small sample of clay ...probably about the size of a 50 cent coin...maybe smaller ....in which all the clay plates were lined up in parallel ...like the pages in a book. He had done this by applying an electrical gradient so that the clay plates lined up .....I think their outer edges were negatively charged...then it was freeze dried. He was using Wyoming Bentonite...the classic clay for this purpose. (And he was looking at water flow through clays where the plates were lined up in the direction of water flow or at right angles to it). But it did occur to me that this regularly organised , electrically active, and common, substance might well have been a template for other chemicals to line up on it....in an ordered and repeatable way.
I've also recently been reading book called "First Life by David Deamer...published in 2011 and there is either no mention or a passing reference to Cairns-Smith's work. (He's mentioned in the biography but not in the index). I think the basic problem is that the chemists don't do soil science nor, in general, clay chemistry which is a huge field all on its own.
The overall thrust of Cairns-Smiths work is to argue that RNA must have had simpler self-organising precursors. And one ubiquitous self organising mechanism is the accretion of crystals. And the various forms of clay crystals (Montmorillonite, kaolinite, rectorite etc.) might just be a template for amino acids to hook up in sequences. He has theories about how all of this might work ...especially the evolution of organic chemicals with the aid of (also evolving) enzymes. And, I think, more recent work by Stuart Kauffman (a somewhat impenetrable writer) also shows that enzymes can evolve and become more efficient with time. Cairns-Smith makes one interesting point about added genes...that they need not be made of the same material as pre-existing genes. He suggests that the sort of genes he's been talking about "would stay together not because of structural similarity but because of functional interdependence. (As grass, sheepdogs, sheep and shepherds are often found in each other's vicinity not because they look alike but because they are useful to each other).....There may be many clever things that can be done with clay platelets, but the sub functions available to the community would be more varied still if other direct acting genetic materials such as fibrous minerals, or later, organic polymers were also included in the community."
Where are these systems now? Well, probably extinct.
In some ways the book now seems rather old fashioned but it was written only 18 or so years after the discovery of the structure of DNA and lots of the genetic machinery was then unknown ....and, I guess, we have come a long way in the last 50 years with our knowledge of biochemistry. But he has intrigued me enough for me to go back and study a bit more clay physics...I have a feeling that with the diffuse double layer of clay with ionic solutions (which always apply) that one can get something like a proton pump...and that appears to be a key ingredient for creating self reproducing molecules. I give the book four stars. It's still interesting even 50 years after publication. ( )