Question

Given diagram shows a pair of homologous chromosomes during meiosis.
Maximum crossing over will occur between genes

• A. A and $a,D$ and $d$
• B. C and d, C and D
• C. B and $C,b$ and C
• D. A and d, a and D.

Answer 1

Answer: (D)

Increase in distance between two genes increases the frequency of crossing over while closeness of the genes reduces the chances of crossing over. Since A and d and a and D are located far away, maximum crossing over would occur between them.