"Genetic and mutant analyses in Drosophila and other standard model organisms have revealed hierarchical gene networks and identified some key regulatory genes acting in animal development. While surprising conservation exists on a broad scale between distant phyla, significant differences have also been detected. Systems biology approaches in the main model systems have now revealed more complex gene regulatory networks (GRNs). To understand the logics and evolution of GRNs more basal animal phyla need to be studied. The comparative analysis of GRNs has thus become a new major focus of systems biology. The key questions are: (1) Does the higher complexity of some species correlate with an increase in complexity in GRNs? (2) How do GRNs evolve to drive changes in body plans? The major challenge for the next generation of researchers will be to integrate knowledge of developmental biology, bioinformatics, functional genomics and evolutionary biology. This requires a new combination of interdisciplinary training to bridge the gap between what are currently quite separate disciplines. In this ITN we will gather and compare information on GRNs from diverse animal systems, representing all major animal lineages, with particular emphases on the mesoderm specification network and the head regionalization network. To this end, we will provide early researchers with the skills necessary to apply state of the art systems biology, genomics and bioinformatics tools to emerging model organisms. The early researchers will receive an in-depth introduction into the selected model systems and training in how to conduct and analyze genomic experiments by the members of this ITN, which includes a company specialized in array technology. We will organize joint ITN/EMBO training courses and summer schools attended by three visiting renowned scientist, an exchange program between the ITN labs and a professional seminar in complementary skills."