My laboratory studies the evolution of developmental mechanisms using molecular, cellular, and genetic approaches. The teleost Astyanax fasciatus is used to study the evolution of eye development. Astyanax populations living in surface streams have large eyes and pigmentation, whereas those adapted to limestone caves have lost their eyes and pigmentation. Astyanax is one of the few cases in which the ancestral and derived developmental states are available for comparative analysis in the same species.
Eye development is initiated in the cave fish embryo but the eye arrests later in development.
We are studying the molecular basis of eye degeneration. Cave fish embryonic lens cells undergo extensive programmed cell death, which has widespread effects on eye development. Transplantation experiments indicate that a lens obtained from a surface fish donor is sufficient to rescue eye development in a cave fish host, showing that the lens is a major regulator of eye degeneration. Current studies include the molecular regulation of lens apoptosis and the antagonism between the pax6, pax2, and midline signaling genes, which appears to be responsible for the regression of eye development in cave fish. We are also studying the evolution of eye regression in different cave fish populations, which appear to have evolved independently.