title: Evolution of eumetazoan nervous systems: insights from cnidarians.
abstract: Cnidarians, the sister group to bilaterians, have a simple diffuse nervous system. This morphological simplicity and their phylogenetic position make them a crucial group in the study of the evolution of the nervous system. The development of their nervous systems is of particular interest, as by uncovering the genetic programme that underlies it, and comparing it with the bilaterian developmental programme, it is possible to make assumptions about the genes and processes involved in the development of ancestral nervous systems. Recent advances in sequencing methods, genetic interference techniques and transgenic technology have enabled us to get a first glimpse into the molecular network underlying the development of a cnidarian nervous system-in particular the nervous system of the anthozoan Nematostella vectensis. It appears that much of the genetic network of the nervous system development is partly conserved between cnidarians and bilaterians, with Wnt and bone morphogenetic protein (BMP) signalling, and Sox genes playing a crucial part in the differentiation of neurons. However, cnidarians possess some specific characteristics, and further studies are necessary to elucidate the full regulatory network. The work on cnidarian neurogenesis further accentuates the need to study non-model organisms in order to gain insights into processes that shaped present-day lineages during the course of evolution.
authors.affiliation: Department of Molecular Evolution and Development, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors.forename: Iva
authors.initials: I
authors.lastname: Kelava
authors.affiliation: Sars Centre, Sars International Centre for Marine Molecular Biology, Thormøhlensgt. 55, 5008 Bergen, Norway.
authors.forename: Fabian
authors.initials: F
authors.lastname: Rentzsch
authors.affiliation: Department of Molecular Evolution and Development, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria ulrich.technau@univie.ac.at.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Technau
mesh_terms: D000818:Animals; D005075:Biological Evolution; D003063:Cnidaria / Q000033:anatomy & histology*; D005786:Gene Expression Regulation; D009420:Nervous System / Q000033:anatomy & histology* / Q000378:metabolism
keywords: Cnidaria; development; evolution; nervous systems; neurogenesis