Two reciprocal Drosophila crosses performed by Morgan

Two reciprocal Drosophila crosses performed by Morgan to determine X-linkage of the gene for eye color. (a) Cross A produces F1 flies that all have red eyes. In the F2 all female flies have red (wild-type) eye color. The F2 males are about one-half red-eyed and one-half white-eyed. (b) Cross B is the reciprocal of Cross A and produces different result in the F1 and F2 generationsTwo reciprocal Drosophila crosses performed by Morgan to determine X-linkage of the gene for eye color. (a) Cross A produces F1 flies that all have red eyes. In the F2 all female flies have red (wild-type) eye color. The F2 males are about one-half red-eyed and one-half white-eyed. (b) Cross B is the reciprocal of Cross A and produces different result in the F1 and F2 generations

(a) Cross A MM 9 Red 6' White uMM 9 Red 6' Red MMMM 9 Red 9 Red 6' Red dWhite (b) Cross 8 ,MM 9 White 6' Red ,MM 9 Red id White MMMM 9 Red 9 White (5' Red d'White Morgan produced 1237 F1 flies, all with red eyes. Morgan’s F2 are 2459 red-eyed females 1011 red-eyed males 782 white-eyed males , Reciprocal of Cross A FI phenotypes differ from Cross A. A 1:1 ratio of red eyes to white eyes is observed in each sex.