In Drosophila, the Y chromosome Y·w+ has a small piece of the X chromosome translocated to it; this piece contains the wild-type alleles of all the genes missing in Df(1)w^rJ1 mentioned in Problem 13.13. If males carrying Y·w+ and a wild-type X chromosome are crossed to Df(1) wrJ1/ClB females, what kinds of progeny will appear, and in what proportions? How would your answer change if the wild-type X chromosome in the males carried a radiation-induced recessive lethal mutation located within the region that is missing in Df(1)w^rJ1? How could these unusual chromosomes be used to devise a scheme that would allow you to carry out complementation tests between two independently induced recessive lethal mutations that map within this region?