Echinoderm systems for gene regulatory studies in evolution and development.

One of the main challenges in Evolutionary Developmental Biology is to understand to which extent developmental changes are driven by regulatory alterations in the genomic sequence. In the recent years, the focus of comparative developmental studies has moved towards a systems biology approach providing a better understanding of the evolution of gene interactions that form the so called Gene Regulatory Networks (GRN). Echinoderms provide a powerful system to reveal regulatory mechanisms and within the past decade, due to the latest technological innovations, a great number of studies have provided valuable information for comparative GRN analyses. In this review we describe recent advances in evolution of GRNs arising from echinoderm systems, focusing on the properties of conserved regulatory kernels, circuit co-option events and GRN topological rearrangements.