Cephalopod retinal development shows vertebrate-like mechanisms of neurogenesis: Multiple sequence alignments and phylogenetic trees

<p>Coleoid cephalopods, including squid, cuttlefish and octopus, have large and complex nervous systems and camera-type eyes that are comparable only to features that have independently evolved in the vertebrate lineage. The changes in development that result in the evolution of nervous system size and diversity of neural cell-types are not well understood. Here, we have pioneered live-imaging techniques and performed functional interrogation to show the squid, <em>Doryteuthis</em> <em>pealeii</em>, utilizes mechanisms during retinal neurogenesis that are hallmarks of vertebrate processes. Given the convergent evolution of elaborate visual systems in cephalopods and vertebrates, these results reveal common mechanisms that underlie the growth of highly proliferative neurogenic primordia that may alter ontogenetic allometry and contribute to the evolution of complex nervous systems.</p>