Match List I with List II –

List I		List II
A	Polymer gene action	I. 9 : 7
B	Complementary gene action	II. 15 : 1
C	Duplicate gene action	III. 13 : 3
D	Inhibitory gene action	IV. 9 : 6 : 1

Correct option is B

The correct answer is (B) A-IV, B-I, C-II, D-III

Explanation:
• Polymer gene action (A) results in a phenotypic ratio of 9:6:1 (IV).
• Complementary gene action (B) occurs when two genes are required together to produce a phenotype, resulting in a 9:7 ratio (I).
• Duplicate gene action (C) occurs when either of two genes can produce the same phenotype, resulting in a 15:1 ratio (II).
• Inhibitory gene action (D) occurs when one gene prevents the expression of another, resulting in a 13:3 ratio (III).

Information Booster:
• These are modifications of the classical Mendelian dihybrid ratio (9:3:3:1) due to gene interactions (Epistasis).
• In Duplicate gene action, only the double recessive genotype (aabb) shows a different phenotype.

Additional Knowledge:
• Recessive Epistasis (Supplementary gene action) gives a ratio of 9:3:4.
• Dominant Epistasis gives a ratio of 12:3:1.