Answer:
Considering that white eyes are a recessive trait in flies, it is possible for two red-eyed flies to have offspring with white eyes only if both are heterozygous for this trait.
Step-by-step explanation:
For two individuals with dominant phenotype for a trait to have offspring with the recessive trait, both must have a heterozygous genotype.
In the case of the characteristic eye color of the flies :
- Red eye (R) is dominant trait.
- White eyes (r) is the recessive trait.
When both parents are heterozygous, their genotype is Rr
In Punnett Square it can see the result of the crossing of these individuals:
Punnett Square :
Rr X Rr
Alleles R r
R RR Rr
r Rr rr
In the offspring, the probabilities are:
- 50% heterozygous individuals Rr, with red eye phenotype.
- 25% pure dominant individuals RR, with red eyes
- 25% individuals with the recessive rr genotype, white eyes.
This is the possibility of two red-eyed flies having white-eyed offspring.