Options have not been provided for the question. They are as follows:
What is the correct order for these genes using a linkage map analysis?
A. Z-X-Y-W
B. X-W-Z-Y
C. W-X-Y-Z
D. Y-W-Z-X
E. Z-X-W-Y
F. Y-X-W-Z
Between which two genes is crossing over most likely to occur?
A. B and D
B.X and Z
C. X and W
D. X and Y
E. W and Z
F. Y and W
G.Y and Z
Answer:
Correct order for these genes using a linkage map analysis: E. Z-X-W-Y
Two genes between which the crossover is most likely to occur: G.Y and Z
Explanation:
According to linkage concept, recombination frequency between two genes = distance between two genes in cM
Here, smallest distance is between X and W ( 7cM ) so they are present next to each other. Distance between X and Y is 17cM and between W and Y is 10cM so W is present between X and Y. Distance between X and Z is 13 cM. Since on one side of X, W and Y are already present Z lies on the other side. So, the final gene order comes out to be, Z-X-W-Y.
According to the gene order, Y and Z genes are farthest from each other. Chances of crossover or recombination increases with increasing distance between genes. So, Y and Z have the highest probability to show crossing over.
