In Drosophila, the genes for eye color, wing shape, and wing length are located
ID: 324134 • Letter: I
Question
In Drosophila, the genes for eye color, wing shape, and wing length are located on chromosome II. Purple eyes (pr), arc bent wings (a), and vestigial wings (vg) are the mutant forms of the wild type traits red eyes, straight wings, and long wings, respectively. You've discovered some data in your genetics laboratory which indicates that the distance between vg and pr is 12.5 m.u., the distance between a and pr is 44.7 m.u., and the distance between a and vg is 32.2 m.u.
If a total of 1250 offspring were obtained from your cross, determine the number of offspring that you would expect to obtain that represent a single crossover event between pr and vg if interference does not occur.
Explanation / Answer
Answer:
Based on the distance between the genes, the order of genes is a--------32.2m.u.---------vg-----12.5m.u.----pr.
As there is no interference, the observed double cross over frequency is equal to expected double cross over frequency.
Distance between the genes= % of recombinanation frequency
Distance between pr---vg is 12.5 m.u.= Recombination between pr---vg is 12.5%.
= (12.5/100) * 1250
= 0.125 * 1250 = 156.25
The number of offspring that you would expect to obtain that represent a single crossover event between pr and vg is 156.25 or 156