Searching for Slit and Robo in the Ascidians, Boltenia villosa and Molgula oculata
The axonal guidance molecules slit and robo are known to interact producing a repulsive signal to the growing processes of nerve cells during development. These signals contribute to the proper ‘wiring’ of nervous systems. Ascidians possess comparatively simple nervous systems, yet still require mechanisms to establish proper synaptic connectivity. In this paper I attempted to identify and clone slit and robo from two ascidians, Boltenia villosa and Molgula oculata. I was unable clone slit or robo sequences from either of these organisms, but was wable to analyze the sequences from the Molgula transcriptome sequences. I constructed gene trees for both genes with available Genbank sequences. These trees grouped vertebrates together, but in both cases the high sequence divergence in the invertebrates resulted in a weak phylogenetic signal leading to a polytomy among the invertebrates.