One of the major challenges in neurobiology is understanding the cellular and molecular mechanisms underlying development of the vertebrate central nervous system (CNS). Research in our laboratory seeks to elucidate these mechanisms by studying development of the vertebrate forebrain and visual system. We study these systems by taking advantage of mutations that affect development of the brain and eye in humans, mice, and zebrafish. Because genetic approaches do not rely on previous assumptions, details about the mechanisms mediating development of the visual system and forebrain can be uncovered that might not be identifiable using other means.