How to build a retina

Professor Harris is fascinated by how an organ as complex and refined as the brain is made during development. His laboratory focuses on the retina, perhaps the most experimentally tractable part of the brain. The key basic and interrelated questions that form the core of his proposed work are: (1) What mechanisms regulate the appropriate number of neurons generated from a population of retinal progenitor cells that themselves produce variable numbers of descendant neurons? (2) In all vertebrates, retinal cells consist of six main types and more than 50 subtypes. How are these types and subtypes generated in the correct proportions? (3) A conserved feature of retinal development is histogenesis, the relationship between cell birth, cell type and tissue architecture. How is this achieved?