Early eye development: Specification and determination

Abstract

Making of an eye requires commitment of cells to adopt an eye tissue fate by the process of retinal specification and determination. Basic molecular mechanisms to form an eye depend upon evolutionarily conserved processes and are controlled by a gene regulatory network called retinal determination network (RDN). The compound eye of the fruit fly, Drosophila melanogaster, has been widely used as an excellent experimental system to understand the genetic mechanisms occurring during eye specification and patterning. In Drosophila, the RDN not only controls eye field determination and patterning of visual anlage in the embryo but also regulates cell proliferation and retinal cell specification from eye-antennal disc at different larval stages. This chapter will highlight mechanisms of early eye specification and determination and will explain how each member of RDN and their genetic interactions guide early eye specification process. This chapter will also emphasize on how RDN controls extraretinal photoreceptor development in the Drosophila larval eye and adult ocelli and will draw attention to our understanding of how early eye fate is determined.