Endless Forms Most Beautiful

Sean B. Carroll (http://seanbcarroll.com/about/) presents a summary of the emerging field of evolutionary developmental biology and the role of toolkit genes. He argues that evolution proceeds by modifying the way that regulatory genes, which do not code for structural proteins (such as enzymes), control embryonic development. In turn, these regulatory genes are based on a very old set of highly conserved genes which Carroll nicknames the ‘toolkit’.  Almost identical sequences can be found across the animal kingdom, meaning that toolkit genes such as ‘Hox’ must have evolved before the Cambrian explosion (https://en.wikipedia.org/wiki/Cambrian_explosion) which created most of the animal body plans that exist today. These genes are used and reused, occasionally by duplication but far more often by being applied unchanged to new functions. Thus the same signal may be given at a different time in development, in a different part of the embryo, creating a different effect on the adult body. In Carroll’s view, this explains how so many body forms are created with so few structural genes. Ironically, complex life could be much simpler than the ‘endless forms most beautiful’ would lead us to believe.


This is a marvellous, rich, and educational book of popular science which I can’t recommend highly enough. Check if this outstanding publication is in stock at your local library by consulting the online catalogue at https://www.sllclibrary.co.uk/cgi-bin/spydus.exe/MSGTRN/OPAC/BSEARCH



368 pages in W.W. Norton & Co.

First published 2005

ISBN 978-0393060164


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Professor Sean B. Carroll

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