Suppose that in Drosophila melanogaster, the allele for red eyes is dominant over the allele for purple eyes, and the allele for a grey body is dominant over the allele for a black body. Also suppose that a testcross was done to check for genetic linkage between the genes for these traits, with the following results for the offspring: 478 flies with red eyes and a black body
27 flies with red eyes and a grey body
462 flies with purple eyes and a grey body
33 flies with purple eyes and a black body
Which of the following best represents the map distance between the genes for these two traits?

Question

Quizplus · Accepted Answer

The map distance between genes is calculated based on the frequency of recombination events. Recombinant offspring are those that exhibit a combination of traits not seen in the parents, indicating a crossover event between the genes. In this case, the recombinant offspring are the ones with red eyes and a grey body (27 flies) and those with purple eyes and a black body (33 flies). To calculate the map distance, you add the number of recombinant offspring (27 + 33 = 60) and divide by the total number of offspring (478 + 27 + 462 + 33 = 1000), then multiply by 100 to get a percentage. So, (60/1000) * 100 = 6.0 map units.

Suppose That in Drosophila Melanogaster, the Allele for Red Eyes