Question

In wild-type Arabidopsis thaliana, the four types of floral organs (sepal, petal, stamen, carpel) are arranged in concentric whorls from outside to inside. With reference to the ABC model of floral organ patterning, match the homeotic mutants in Group 1 with their respective arrangements of organs in the four whorls given in Group 2.

 

• A. ( {P - iv, Q - ii, R - i} )
• B. ( {P - iii, Q - i, R - ii} )
• C. ( {P - ii, Q - i, R - iii} )
• D. ( {P - iii, Q - i, R - iv} )

Hint:

The ABC model explains how combinations of gene activities determine the identity of floral organs in different whorls of a flower.

Answer 1

The Correct Option is B

According to the ABC model of floral organ patterning: - A class mutants (P): Loss of A function results in the expression of C function throughout the flower, leading to the formation of carpels in the outer two whorls (iii: carpel, stamen, stamen, carpel). - B class mutants (Q): Loss of B function results in sepals forming in the first and second whorls, and carpels forming in the third and fourth whorls (i: sepal, sepal, carpel, carpel). - C class mutants (R): Loss of C function results in the expression of A function throughout the flower, leading to the formation of sepals and petals only (ii: sepal, petal, petal, sepal). Thus, the correct answer is ( {P - iii, Q - i, R - ii} ), corresponding to option (B).