Q18 / 180 · NEET 2026 (Cancelled) · Botany

Match List I with List II :
List IList II
A. Incomplete dominanceI. Human skin colour
B. Co-dominanceII. Inheritance of flower colour in Antirrhinum sp.
C. PleiotropyIII. Phenylketonuria disease in humans
D. Polygenic inheritanceIV. ABO blood groups

Choose the correct answer from the options given below :

  • Correct answer
    A
    A-II, B-IV, C-III, D-I
  • B
    A-I, B-III, C-II, D-IV
  • C
    A-IV, B-III, C-II, D-I
  • D
    A-II, B-I, C-III, D-IV

Solution

Incomplete dominance is observed in the inheritance of flower colour in Antirrhinum sp. (snapdragon), where the heterozygous phenotype is intermediate between the two homozygous phenotypes.

Co-dominance is exhibited by ABO blood groups in humans, where both alleles $I^A$ and $I^B$ express themselves fully in a heterozygous individual.

Pleiotropy occurs when a single gene influences multiple phenotypic traits. Phenylketonuria is an example of pleiotropy in humans, where a single gene mutation leads to mental retardation and a reduction in hair and skin pigmentation.

Polygenic inheritance involves traits controlled by three or more genes, such as human skin colour.

Therefore, the correct matching is A-II, B-IV, C-III, D-I.

Answer: A-II, B-IV, C-III, D-I

Hence, the correct answer is option: 'A'.

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