"Two blind fish can make sighted offspring.
By mating blind fish from distant underwater caves, researchers have bred offspring that can see.
The results, published this week in Current Biology1, show that the two populations took different evolutionary paths to blindness.
“We’ve basically shown that these different populations have converged upon the same outward appearance independently, and that they use different genes to do it,” says Richard Borowsky of New York University.
The blind fish, called Astyanax mexicanus, live in isolated limestone caves in northeast Mexico. Over hundreds of millennia of living in darkness, the fish, which have a sighted ancestor, accumulated genetic mutations that affect eye development, and so lost their sight. Today some 29 different varieties of the blind Mexican fish live in isolated caves. Researchers have long wondered whether they all lost their sight the same way or not. (...)"