Development gene networks and evolution.

Animal development relies on complex programs of gene regulation that are likely to account for a significant fraction of the information carried in genomes. The evolution of these regulatory programs is a major contributor to the diversity of animal forms, yet the architecture of the transcriptional networks that comprise developmental programs is only beginning to come into focus. The sea urchin offers an uncomplicated system in which to study transcriptional regulation and the networks that direct embryogenesis. This review describes the approaches that we are taking towards this problem using the sea urchin embryo and some comparative methods that will eventually lead to a deeper understanding of the evolution of developmental networks.