Match List-I with List-II
| List-I | List-II |
|---|---|
| Types of inheritance | Examples |
| (A) Pleiotropy | (I) ABO blood grouping in human |
| (B) Polygenic inheritance | (II) Snapdragon plant |
| (C) Incomplete dominance | (III) Phenylketonuria |
| (D) Co-dominance | (IV) Human skin colour |
Choose the correct answer from the options given below.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A) - (III), (B) - (IV), (C) - (II), (D) - (I)
(A) Pleiotropy — this matches (III) Phenylketonuria. In pleiotropy a single gene shows more than one effect on the phenotype. In phenylketonuria one mutated gene, for the enzyme phenylalanine hydroxylase, leads to mental retardation and also to less pigment in the hair and skin.
(B) Polygenic inheritance — this matches (IV) Human skin colour. Here a trait is controlled by three or more genes, and each dominant allele adds a little to the effect. So skin colour does not come in two or three types but in many shades, from very dark to very light.
(C) Incomplete dominance — this matches (II) Snapdragon plant. In the dog flower (snapdragon), a cross of red (RR) and white (rr) gives pink (Rr) flowers: neither allele is fully dominant, so the hybrid is in between. The F2 ratio is 1 red : 2 pink : 1 white.
(D) Co-dominance — this matches (I) ABO blood grouping in human. The alleles IA and IB are both fully expressed when present together, so a person with IAIB has both sugars on the red blood cells and belongs to group AB.
Note: A similar question was also asked in CUET (UG) 2026 on 21-05-2026 (Slot 2).