Question

6. Now consider a homozygous red eyed, curly winged fly with a pink eyed, heterozygous straight winged fly. Predict the offspring that would be produced by this cross (genotypes, phenotypes, and probability of each).

Answer 1

Additional information is missing. It is as follows: In fruit flies, the allele for red eyes is dominant over the allele for pink eyes. Straight wings are dominant over curled wings.

Answer:

Genotype = RrSS and RrSs in 1:1 ratio so each has 0.5 probability

Phenotype = All red eyed and straight winged

Step-by-step explanation:

Given,

Red eyes (R) is dominant over pink eyes (r)

Straight wings (S) is dominant over curled wings (s)

Fly 1 : Homozygous red eyed, curly winged = RRss

Fly 2 : Pink eyed, heterozygous straight winged = rrSs

RRss will produce Rs gametes and rrSs will produce rS and rs gamates.

When fly 1 and fly 2 mate : RRss X rrSs :

rS rs

RS RrSS RrSs

The genotypic ratio is 1 : 1 ( RrSS : RrSs ) that means that each genotype has 0.5 probability. Both the genotypes though have at least one dominant allele for each gene so the entire progeny will have red eyes and straight wings.