Abiogenesis - Other Models - Clay Hypothesis

Clay Hypothesis

A model for the origin of life based on clay was forwarded by A. Graham Cairns-Smith of the University of Glasgow in 1985 and explored as a plausible illustration by several scientists. The Clay hypothesis postulates that complex organic molecules arose gradually on a pre-existing, non-organic replication platform of silicate crystals in solution.

Cairns-Smith is a trenchant critic of other models of chemical evolution. However, he admits that like many models of the origin of life, his own also has its shortcomings.

In 2007, Kahr and colleagues reported their experiments that tested the idea that crystals can act as a source of transferable information, using crystals of potassium hydrogen phthalate. "Mother" crystals with imperfections were cleaved and used as seeds to grow "daughter" crystals from solution. They then examined the distribution of imperfections in the new crystals and found that the imperfections in the mother crystals were reproduced in the daughters, but the daughter crystals also had many additional imperfections. For gene-like behavior to be observed, the quantity of inheritance of these imperfections should have exceeded that of the mutations in the successive generations, but it did not. Thus Kahr concluded that the crystals, "were not faithful enough to store and transfer information from one generation to the next".