Question

Refer to the given figure of cross A and cross B and select the correct statement regarding them.

Note: (+) sign in superscript represents dominant wild type alleles

• A. In cross $A$ , the strength of linkage between genes $y$ and $w$ is higher than the cross $B$ genes $w$ and $m$ .
• B. In cross $A$ , the strength of linkage between genes $y$ and $w$ is lesser than the cross $B$ genes $w$ and $m$ .
• C. Both cross $A$ genes y and w and cross $B$ have the same strength of linkage.
• D. The percentage of recombinants produced in cross $A$ is higher than cross $B$ .

Answer 1

Answer: (A)

The physical distance between two genes tells us about the linkage and also tells us about the crossing over. If the distance between two genes is less then the linkage will be more and cross over will be less. Similarly, if the distance between two genes is more then the linkage between them will be less and cross over will be more. As we can see in the first diagram the distance between two genes i.e. y and w is less than the cross over will be maximum there in comparison to the second diagram where genes i.e. w and m present at the greater distance. The strength of the linkage will be more in cross A as compared to cross B.