Question

Assertion (A): In Drosophila, the recombination frequency of the genes responsible for the eye colour and wing size is more than that of body colour and eye colour.
Reason (R): In Drosophila, the gene responsible for eye colour is more closely located to the gene for body colour as compared to the gene for wing size.
[0.7 mark]

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true and R is not the correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Answer 1

The correct option is A Both A and R are true and R is the correct explanation of A

In dihybrid cross, conducted by Morgan, recombinant type Drosophila w.r.t. eye colour and wing size was 37.2% whereas for body colour and eye colour was only 1.3%. This is because, the genes for eye colour and wing size is farther from each other as compared to the genes for eye colour and body colour.
The recombination frequency depends upon the distance between the genes. If the distance between the genes is lesser, the recombination frequency is also lesser.