Answer:
15
Explanation:
The genes for vestigial wings (vg) and purple eyes (pr) are linked on the same chromosome.
<u>The following cross was made:</u>
Heterozygous male for both genes X female<em> vg pr / vg pr</em>
The male could be either <em>vg+pr+/vg pr</em> or<em> vg+ pr/vg pr+</em>.
The female only produces <em>vg pr </em>gametes.
<u>The following offspring was observed: </u>
420 Normal wings and red eyes (<em>vg+ pr+/vg pr</em>)
430 Vestigial wings and purple eyes (<em>vg pr / vg pr</em>)
80 Vestigial wings and red eyes (<em>vg pr+ / vg pr</em>)
70 Normal wings and purple eyes (<em>vg+ pr / vg pr</em>)
Total: 1000
The individuals observed in the highest frequency have the parental genotypes. The recombinant individuals are <em>vg pr+ / vg pr</em> and <em>vg+ pr / vg pr.</em>
Distance = Number of recombinants × 100 / Total
Distance = (80 + 70)×100 / 1000
Distance = 15 cM.
<em>Just a small note, male drosophila do not experience crossing over in meiosis, so there would be no recombinants observed from this cross. The problem is probably mixed up, the female should be heterozygous and the male the homozygous recessive.</em>
