In Drosophila melanogaster, wing-size and body-color genes are linked. Vestigial wings and black body color are both recessive traits. A researcher crossed black-bodied, normal-winged females and gray-bodied, vestigial-winged males. The F1 were all gray bodied, normal winged. A test cross was performed with F1 females. The researcher calculated a map distance of 17 map units. Which of the following information is correct about the testcross progeny?

Question

Quizplus · Accepted Answer

The map distance of 17 map units between the genes for wing size and body color indicates the percentage of recombinant offspring, which are the non-parental types. In this case, black-bodied, normal-winged flies and gray-bodied, vestigial-winged flies are the recombinant types, each representing 17% of the total, making their combined percentage 34%. However, the correct interpretation of the given information is that each of these recombinant types represents half of the recombinants, thus each type accounts for 8.5% of the total, leading to a misunderstanding in the explanation. The correct understanding is that the map distance reflects the total percentage of recombinant offspring, which are the sum of both types of recombinant progeny.

In Drosophila Melanogaster, Wing-Size and Body-Color Genes Are Linked