Use the following information to answer the question.

In a series of mapping experiments, the recombination frequencies for four different linked genes of Drosophila were determined as shown in the figure. Based on this information, what is the order of these genes on a chromosome map?
A) rb-cn-vg-b
B) cn-rb-b-vg
C) b-rb-cn-vg
D) vg-cn-b-rb

Question

Use the following information to answer the question.

In a series of mapping experiments, the recombination frequencies for four different linked genes of Drosophila were determined as shown in the figure. Based on this information, what is the order of these genes on a chromosome map?
A) rb-cn-vg-b 
B) cn-rb-b-vg 
C) b-rb-cn-vg 
D) vg-cn-b-rb

Quizplus · Accepted Answer

The order of the genes on the chromosome map can be determined by arranging them in the order of increasing recombination frequency. 
The lowest recombination frequency is between b and rb (9.5%), followed by rb and cn (17%), then cn and vg (21.5%), and the highest is between vg and b (26%). 
Therefore, the order of these genes on the chromosome map is b-rb-cn-vg, which corresponds to choice C.

Use the Following Information to Answer the Question