Segmentation is a key feature of arthropod diversity and evolution. In the standard model for arthropod development, Drosophila melanogaster, segments develop simultaneously by a progressive subdivision of the embryo. By contrast, most arthropods add segments sequentially from a posterior region called the growth zone and in a manner similar to vertebrates.
Recent work, mainly focused on insects, suggests that Notch signaling might play a role in arthropods that segment sequentially. These studies document a potential regulatory similarity between sequentially segmenting arthropods and vertebrates. In vertebrates, somite formation involves a molecular oscillator that functions as a pacemaker, driving periodic expression of genes along the anterior-posterior axis.
Here we focus on segmentation in crustaceans, the sister taxon to insects. We investigate the relationship between Notch signaling and segmentation in the fairy shrimp, Thamnocephalus platyurus. In order to explore gene regulation of segmentation in these animals, we will be tracing expression of Notch pathway genes using in situ hybridization and investigating their functions by using a chemical inhibitor of the Notch pathway