Gene Regulatory Networks and the Evolution of Animal Body Plans

Un article en fichier joint d' Eric H. Davidson et Douglas H. Erwin paru dans Science le 10 février 2006

Eric H. Davidson1* and Douglas H. Erwin2
1 Division of Biology 156-29, California Institute of Technology, Pasadena, CA 91125, USA._
2 Department of Paleobiology, MRC-121, National Museum of Natural History, Post Office Box 37012, Washington, DC 20013–7012, and Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA.
∑ To whom correspondence should be addressed. E-mail: davidson [at] caltech [dot] edu

Abstract :
Development of the animal body plan is controlled by large gene regulatory networks (GRNs), and hence evolution of body plans must depend upon change in the architecture of developmental GRNs. However, these networks are composed of diverse components that evolve at different rates and in different ways. Because of the hierarchical organization of developmental GRNs, some kinds of change affect terminal properties of the body plan such as occur in speciation, whereas others affect major aspects of body plan morphology. A notable feature of the paleontological record of animal evolution is the establishment by the Early "Cambrian of virtually all phylum-level body plans. We identify a class of GRN component, the kernels" of the network, which, because of their developmental role and their particular internal structure, are most impervious to change. Conservation of phyletic body plans may have been due to the retention since pre-Cambrian time of GRN kernels, which underlie development of major body parts.

Ce papier introduit à un véritable changement de paradigme. Il montre que les possibilités d’action de la sélection naturelle sont fortement limitées et que les plans de base des grandes catégories d’organismes n’ont pas pu se modifier depuis 500 millions d’années ! Il a suscité des réactions passionnées et ouvert des nouvelles voies de recherches.

Se trouve sur :
http://www.sciencemag.org/cgi/reprint/313/5788/761c.pdf?ck=nck