Central role for the lens in cave fish eye degeneration

Astyanax mexicanus is a teleost with eyed surface-dwelling and eyeless cave -dwelling forms. Eye formation is initiated in cave fish embryos, but the e ye subsequently arrests and degenerates. The surface fish lens stimulates g rowth and development after transplantation into the cave fish optic cup, r estoring optic tissues lost during cave fish evolution. Conversely, eye gro wth and development are retarded following transplantation of a surface fis h lens into a cave fish optic cup or lens extirpation. These results show t hat evolutionary changes in an inductive signal from the Lens are involved in cave fish eye degeneration.