Book review: Seven Clues to the Origin of Life by Alexander Graham Cairns-Smith

I found this book while doing research for my Extended Project, the focus of which is the RNA World hypothesis and the Miller-Urey experiment. By the time I got to the end of the book, I was convinced that neither of these were plausible explanations for the origin of terrestrial life, because Alexander Graham Cairns-Smith had utterly persuaded me that his own hypothesis was correct.

Seven Clues to the Origin of Life presents the argument that the first molecules of life were assembled on clay, which provided a template on which inorganic crystals could self-replicate. Despite the fact that there is ingenious science within the pages of the book, I found it light-hearted and enjoyable reading which was accessible for all as well as gripping. The book assumes very little prior knowledge of chemistry and biology, with the first couple of chapters introducing some fundamental principles and discussing the molecules of life. The whole thing was narrated in a detective novel style, with quotes from the original Sherlock Holmes books by Conan Doyle at the start and end of each chapter; and the intelligent use of analogies to illustrate core concepts was excellent. In particular, I liked the “scaffolding” idea, illustrating how seemingly interdependent, complex processes could have arisen from simpler building blocks, some of which were later removed. I appreciated the escape from the logic that, since nucleic acids and proteins are interdependent in today’s cells, the first organisms must have been based on RNA, as I just don’t think the random synthesis of active RNA molecules under prebiotic conditions is really plausible (again, Cairns-Smith cleverly argues this by comparing it to the probability of rolling a million 6s on a dice in a row).

The hypothesis itself was a courageous one, deviating largely from most of the current theories mainly in that it suggests that the first life forms were inorganic. Concepts such as supersaturation and self-assembly are explained with clarity and detail, while still capturing the reader’s excitement as the picture is gradually built up, describing how crystals could have formed and replicated on clay surfaces and hence acted as genes, with errors in replication leading to “evolution by direct action”.

The core theme of studying the most perplexing features of a case in order to crack it is well maintained throughout, making for enjoyable reading as well as learning. I found Seven Clues to the Origin of Life a superb book, one that should be read at the very least by anyone with an interest in the chemical origins of life, and preferably by anyone with an interest in chemistry and biology.