BOB HIRSHON (host):
New eyes for blind fish. I’m Bob Hirshon and this is Science Update.
Mexican cave fish are blind. Living in complete darkness, they have rudimentary eyes that don’t even sense light. But when researchers at New York University bred cave fish from different caves, the offspring not only had eyes, but they could see. Evolutionary biologist Richard Borowsky explains that this is probably because each population of cave fish has independently evolved a different set of faulty eye genes.
RICHARD BOROWSKY (New York University):
And so when you hybridize them, the strengths of one cave population make up for the weaknesses of the other cave population in the hybrids and you get this restoration of function.
He says eyes take a lot of energy to maintain. So in the absence of light, natural selection favored fish with poor eyesight. I’m Bob Hirshon, for AAAS, the science society.