A single gene which can exhibit multiple phenotypic expression is called as:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Pleiotropic gene
A gene that affects more than one trait is called a pleiotropic gene. One gene shows multiple phenotypic expression because it acts on a metabolic pathway that feeds into different traits. The disease phenylketonuria in humans is an example.
(1) Epistatic gene — Incorrect. An epistatic gene masks the effect of another gene at a different locus. It does not show many traits by itself.
(2) Multiple gene — Incorrect. This is not the term used for it. Several genes controlling one trait are called polygenes.
(3) Pleiotropic gene — Correct. One gene, many phenotypic effects.
(4) Polygenic gene — Incorrect. The feature is reversed here. In polygenic inheritance, many genes control one trait, as with human skin colour. In pleiotropy, one gene affects many traits.
NCERT Extract:
Pleiotropy –
