Two blind fish can make sighted offspring.
“The offspring of crossbred blind cave fish see like their surface-dwelling cousins.
The results in Current Biology 1, 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.”
This is the type of thing that RM and NS can do. I would say that they lose different genes to become blind, not use different genes.