Drosophila (fruit flies)usually have long wings (+ is the symbol used to represent this allele),but mutations in two different genes can result in bent wings (bt)or vestigial wings (vg).The bent and vestigial wing alleles segregate independently.In symbolizing fruit fly alleles,it is common to use two letters as opposed to only one.If flies that have long wings and are heterozygous for both the bent wing gene and the vestigial wing gene are mated,what is the probability of offspring with bent wings only?

Question

Quizplus · Accepted Answer

First, we need to determine the genotype of the parent flies. Since they have long wings and are heterozygous for both bent and vestigial wing genes, their genotype would be LlBbVv. When we cross these two flies, we can use the Punnett square method to determine the offspring genotype.

|   | LB   | Lb   | lB   | lb   |
|---|------|------|------|------|
| Vb| LBVb | LbVb | lBVb | lbVb |
| vb| LBvb | Lbvb | lBvb | lbvb |

From the Punnett square, we can see that there are 16 possible offspring genotypes. To determine the probability of offspring with bent wings only, we need to add up the probabilities of all the offspring with bent wings only: LbBbVv, LbbBbVv, lbBbVv, lbbBbVv.

LbBbVv = 1/16
LbbBbVv = 1/16
lbBbVv = 1/16
lbbBbVv = 1/16

The total probability of offspring with bent wings only is 1/16 + 1/16 + 1/16 + 1/16 = 4/16 = 1/4. Therefore, the answer is D) 3/16.

Drosophila (Fruit Flies)usually Have Long Wings (+ Is the Symbol