University of Maryland biologists have identified how changes in both behavior and genetics led to the evolution of the Mexican blind cavefish (Astyanax mexicanus) from its sighted, surface-dwelling ancestor.
The blind cave fish of Mexico – Astyanax mexicanus is a popular and unusual aquarium fish. It’s one of around 80 species of blind cave fish found throughout the world. What makes this fish really interesting is that the fish from which it evolved is still swimming around in the surface waters of Mexico. In fact the blind form has evolved so recently that full speciation has not yet occurred and the two forms, sighted and blind, are considered to be the same species and can even interbreed.
Read more here – Science Daily.