Expert opinion: From crystals to cancer: the 50th anniversary of Cairns-Smith's startling hypothesis
It is now 50 years since Graham Cairns-Smith suggested that life may have originated from crystals, rather than directly through complex carbon-based molecules such as proteins and DNA.
His ideas were based on observations that many crystals, especially those found in clay, have subtly different patterns, and that "daughter" crystals can inherent these patterns when they grow from a fragment of the original. Furthermore, during the process of growth, "mutations" can arise in the crystalline structure, and these too can be passed on to the crystal’s progeny. These properties of crystals are generally accepted, although Cairns Smith’s idea that at some point these crystals used carbon-based molecules to help them divide and that these in turn became molecules such as proteins and DNA have never been supported by experimental evidence, although to be fair relatively very little effort has been made to study this in the lab.
Despite the lack of evidence to support this route to life, Cairns-Smith’s ideas continue to be debated as currently there are few alternatives that seem remotely plausible, including the concept of a random "accident" in a complex soup of chemical precursors. It is quite possible that there will never be convincing experimental evidence to support Cairns-Smith’s ideas, and even if there was there would be no way of knowing if these events actually occurred billions of years in the past. Returning to the "biology" of crystals though, there have been some particularly intriguing observations that have a striking parallel to cancer. These are the occurrence in some crystals of “inheritable” changes that cause them to fragment far more easily than their parents, allowing them to replicate far more quickly. These smaller crystals then have the potential to form disorganized structures that might be considered similar to tumors. Whether or not life had a crystalline origin, these observations indicate that rapid division and mutation may be an inevitable part of any process that mimics life.
Looking forward
Some of these fundamental questions underlying the origins of life and disease may not be solvable today, but the undergraduate courses offered in Bradford, especially Biomedical Sciences and Chemistry, will help provide future scientists with the skills needed to address them. These courses cover the fundamental basis of disease processes such as cancer, as well the key chemical processes that underlie life, and aim not only to answer questions, but help students understand which are the important questions to ask.
, Director, Institute of Cancer Therapeutics reacting to BBC News article on The idea that life began as clay crystals is 50 years old.