A. G. Cairns-Smith

Now this book is really hard-going. Took me ages to read. The section on "First biochemicals" was especially hard-going bit is, as the author says "a long pause for information". And I can see why it was necessary. I think this book was Grahame Cairn-Smith's magnum opus and he was probably hoping to kick-start a new paradigm in life sciences....specifically in regard to the origins of life. Somehow, it didn't seem to take-off. And, maybe, one of the reasons for it was that this book requires quite a lot of both dedication and some background to follow....and maybe not too many people were prepared to put in the effort.
The title encapsulates his main message and that is that somewhere along the line nucleotides and amino acids evolved from something else: something simpler and something that was mineral based. He espouses the view that there was some form of mineral evolution that provided the templates for organic chemicals to develop and reproduce and once this happened the organic chemicals just took over and supplanted their earlier mineral based ancestry. (And, apparently, in the process, erased the signs of this ancestry. This step was what Cains-Smith describers as 'genetic takeover".
He favours the idea that clays are ideal candidates for the precursors of organic chemicals...or, at very least, they could be templates for replication and growth. There is an overwhelming amount of information and detail in the book ...so much so that it is hard to take it all in.
I did come away with the impression that Cairns-Smith has an unending series of examples of ways things MIGHT have developed ....some of them rather far-fetched but possible. But he's very weak on real examples of sequences of events that lend weight to his case.
I did think that he might have made more out of some of the evolutionary sequencing that seems to occur with Kaolinite changing into Allosite or similar natural sequence and I would have liked to have seen some situations with a bit more detail like that suggested in Fig 9.5 (p383).
But maybe Cairns-Smith was not the right person to take the proposal to the next level and, unfortunately, nobody else seems to have stepped up to the plate in the last 50 years.
I recently read the book "First Life" by David Deamer and it seems to be the current state of the art with "origins of life" theory. But rather disappointing and there is virtually no mention of Cairns-Smiths ideas. In fact, Deamer reveals his profound ignorance of clays and their absorptive capacity by taking an experiment to a volcanic pool in Siberia and basically dropping it in to see what would happen. Seems very naive to me:.......the clay immediately grabbed (adsorbed) all his organic chemicals ...and that was that.
Somewhere in Cairn's writings, he mentions that he took his ideas to the USA: The geologists thought his geology was fine but weren't quite sure about his biochemistry; The biochemists were happy with the biochemistry but thought the geology might be a bit suspect; The Chemists were happy with the Chemistry but thought the Geology needed some work...etc. I think that Deamer has little or no knowledge of clay Chemistry and probably most scientists around today are similar in that their knowledge doesn't roam over as broad a field as Cairns-Smith is attempting to embrace. A pity, because I think that Cairns-Smith might actually be onto something here. I won't try to summarise his data or arguments....there is too much there. But I did find it a fascinating book and happy to give it 5 stars.… (mer)

What does one do after you've written a major scientific work that you expect will launch a new paradigm? Well, if you are an academic, I guess the next step is to organise an international conference; give it a great title ("Clay Minerals and the Origin of Life"....I mean what more could you ask for?) and wait for the best and brightest to show up...like they did for the Solvay conferences in Physics.
It seems to me that this is what AG Cairns-Smith has done but it doesn't really seem to have taken off by my reading. I was rather disappointed with this set of proceedings of the conference. I guess, like most conferences of this nature a lot of people who like to travel internationally and either catch up with their mates or meet some "big names' ...try to shoe-horn whatever work they happen to be doing at the moment into a paper that might be accepted by the organisers. And if the organisers are sufficiently desperate, they will accept it. I feel the something like this has happened with this book.
Most of the book is devoted to clay structure; the origin of clays on earth and artificial synthesis of clays (which is not really the issue.....there are plenty of clays around). Clays in the solar system and what sort of clays are on Mars. Now most of this appears to be off-subject to me. I was looking for the link between clay and RNA or between mineral chemistry and organic chemistry...and they don't really get around to discussing this until the last few pages with the editors having a discussion.....which apparently is actually an "imaginary conversation". (A conversation which "might" have happened....but didn't.

There is a section there about the catalytic effect of clays on organic matter and maybe this is getting closer to the real subject ...but there is still a significant gap between clays and organic matter in the first place. It wasn't really until p135 (in a 158 pages of actual content) that J G Lawless of NASA Ames Research Centre in California seems actually tackle the subject of the conference. His suggestions are illuminating...maybe even slightly persuasive but by no means a demonstration of a link between clays and biochemistry. He mentions the possibility that "The clay surface and specific sites therein have been proposed to act as direct templates for the production of a repeated, select sequence of biomolecules (eg., amino acids and 5-nucleoside monophosphate or related compounds) in the formed bio-oligomers." This seems to me to be getting somewhere where most of the other papers meander around the general subject of clays but don't actually come to grips with the origins issue.

Bloch enunciates a series of stages that could elaborate on phenotype for clays:
1. Replication as phenotype
2. Selection for responsiveness to environment
3. Selection for gratuitous nutritional requirement
4. Selection for a productive phenotype.
5. Positive feedback
6. Mutualism
7. A program for elimination of regressive variants.
8. Development of a mainline nutritive requirement.
9. Discriminating (exclusive) feedback.

But the ways that clays could follow this sequence are not well spelled out to my way of thinking. Or, at least there is a lack of continuity with the stages.

Overall, I was disappointed in the book. I was hoping for a lot more but it seems that AG Cairns-Smith's ideas, really just haven't taken off. (I actually had to go to a lot of trouble to access the one copy of this book that appears to be available in Sydney).
One of the reasons for this, I think, is that Cairns-Smith himself is really very woolly when it comes to showing how clay genes might actually work: it's at a very abstract level, when what is needed is some sort of more realistic sequence that is recognisable as evolution and maybe replication.
I give it three stars.… (mer)

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.… (mer)