Conservation of neurogenic genes and mechanisms

Reports from the past year have demonstrated that neural basic helix-loop-h elix genes and LIM homeobox genes contribute to neuronal subtype specificat ion in vertebrates and invertebrates, that Notch signaling specifies cell f ates in the developing vertebrate inner ear, and that the organization of t he central nervous system into three columns is shared by vertebrates and i nvertebrates. These findings pave the way for future work that will help to establish the extent to which these similarities represent evolutionary co nservation.