Monday, 17 May 2010

The Evolution of Form and Function - The Testing of a Hypothesis

I've been a fan of Sean Carroll's work for a while now and thoroughly recommend his book Endless Forms Most Beautiful  to anyone who wants to understand the evolution of form (something I am very interested in). In it he elucidates the science of evo-devo and how form such as limbs and patterns can evolve. It is not surprising that the evolution of morphology attracts the interest of palaeontologists, of which I recommend the work of Neil Shubin. Carroll's second book The Making of the Fittest is also a great read (easier than the first) though it is the evolution of form that I am discussing now.

In 2005 Sean Carroll hypothesised that changes in morphology (outward appearance) were due to changes in gene regulation, whereas physiological changes (the inner workings) were due to changes in protein structure and function. This hypothesis was initially controversial and was recently investigated by a team from the University of Michigan. The genetic analyses strongly support Carroll's hypothesis. They identified 900 "morphogenes" which affected only morphology and around 900 "physiogenes" affecting physiology. Morphogenes were found to carry instructions for transcription, whereas physiogenes were often blueprints for enzymes, receptors, transporters and ion channels. When these genes were analysed to determine evolutionary rates. Physiogenes were found to evolve quicker at the protein sequence level, whereas morphogenes evolved quicker with respect to changes in expression.

This is great insight both for evolutionary biology and for the study of genetic processes in human disease. For more info:

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