Question: 98 The phenomenon of pleiotropism refers to
(1) a single gene affecting multiple phenotypic expression.
(2) more than two genes affecting a single character.
(3) presence of several alleles of a single gene controlling a single crossover.
(4) presence of two alleles, each of the two genes controlling a single trait.
Answer: Option (1)
Explanation:
Pleiotropism is a genetic phenomenon in which one gene influences more than one phenotypic character.
This occurs because a single gene product may be involved in multiple biochemical pathways or developmental processes.
As a result, mutation or variation in that gene leads to multiple phenotypic effects.
Therefore, pleiotropism refers to a single gene affecting multiple phenotypic expressions.
Hence, the correct answer is Option (1).