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

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, Doryteuthis pealeii, 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.