In Drosophila, round eyes (rai+) (wildtype) are dominant to raisin eyes (rai). A
ID: 227112 • Letter: I
Question
In Drosophila, round eyes (rai+) (wildtype) are dominant to raisin eyes (rai). A heterozygous fly is crossed with a homozygous recessive fly. then What is the correct genotypic and phenotypic ratios for the F1 progeny?
Genotype
1:2:1, rai+/rai+ : rai+/rai : rai/rai
1:1, rai+/rai+ : rai/rai
1:1, rai+/rai : rai/rai
3:1, rai/rai : rai+/rai
Phenotype
4:0, round eyes
3:1, raisin eyes : round eyes
1:1, round eyes : raisin eyes
4:0, raisin eyes
Genotype
1:2:1, rai+/rai+ : rai+/rai : rai/rai
1:1, rai+/rai+ : rai/rai
1:1, rai+/rai : rai/rai
3:1, rai/rai : rai+/rai
Phenotype
4:0, round eyes
3:1, raisin eyes : round eyes
1:1, round eyes : raisin eyes
4:0, raisin eyes
Explanation / Answer
In a cross between heterozygous fly and a homzygous recessive fly,
Phenotype: Round Eyes * Raisin Eyes
Genotype : rai+/ rai rai/rai
Gametes: rai+ , rai rai , rai
Genotype of Progeny: rai+/rai , rai+/rai , rai/rai , rai/rai
Genotypic ratio : 1: 1 (rai+/rai : rai/rai)
Phenoype: Round, Round, Raisin, Raisin
Phenotypic ratio: 1:1 (Round : Raisin)