Modern genetics began in a laboratory at Columbia University in New York City in 1910. There, Thomas Hunt Morgan and a group of very talented students, working with Drosophila, discovered most of the rules of genetics as we currently understand them.

Morgan spent over a year breeding flies and looking for variations from the wild-type. As you have seen, Drosophila normally have bright red eyes. One day, in one of his culture bottles, Morgan noticed a male fly with white eyes. He crossed this mutant with a red-eyed female. All of the offspring of the cross had red eyes, as would be expected in the case of a recessive mutation.

Morgan then mated the flies in this second generation to each other. What kinds and frequencies of offspring would you expect to see in such a cross?

Answer