A dominant mutation B results in brown eyes rather than thewildtype red eyes in Drosophila. Genotypes BB and Bb therefore havebrown eyes, whereas genotype bb has red eyes. The mutation showscomplete penetrance and is located on one of the autosomes. Ageneticist carries out a cross of homozygous brown (BB) byhomozygous red (bb). The following questions pertain to crossesmade using the F1 progeny of this cross, all of which have theheterozygous genotype Bb.
a.The F1 male and female progeny are matedtogether to produce an F2 generation. From the F2 generation, alarge number of brown-eyed males, taken at random, are mixedtogether in a bottle containing homozygous bb females. Whatgenotypes and phenotypes would be expected among the progenyemerging from this bottle, and in what proportions?
b. The F1 male and female progeny are mated together to producean F2 generation. The brown-eyed F2 males and brown-eyed F2 femalesare mated at random. What genotypes and phenotypes would beexpected among the progeny, and in what proportions?
A dominant mutation B results in brown eyes rather than thewildtype red eyes in Drosophila. Genotypes BB and Bb therefore havebrown eyes, whereas genotype bb has red eyes. The mutation showscomplete penetrance and is located on one of the autosomes. Ageneticist carries out a cross of homozygous brown (BB) byhomozygous red (bb). The following questions pertain to crossesmade using the F1 progeny of this cross, all of which have theheterozygous genotype Bb.
a.The F1 male and female progeny are matedtogether to produce an F2 generation. From the F2 generation, alarge number of brown-eyed males, taken at random, are mixedtogether in a bottle containing homozygous bb females. Whatgenotypes and phenotypes would be expected among the progenyemerging from this bottle, and in what proportions?
b. The F1 male and female progeny are mated together to producean F2 generation. The brown-eyed F2 males and brown-eyed F2 femalesare mated at random. What genotypes and phenotypes would beexpected among the progeny, and in what proportions?
