NEET 2023
- Exam
- NEET
- Year
- 2023
- Subject
- Zoology
- Chapter
- Principles of Inheritance and Variation
NEET 2023 · Zoology · Principles of Inheritance and Variation
The phenomenon of pleiotropism refers to:
The phenomenon of pleiotropism refers to:
Options
- AMore than two genes affecting a single character.
- BPresence of several alleles of a single gene controlling a single crossover.
- CPresence of two alleles, each of the two genes controlling a single trait.
- DA single gene affecting multiple phenotypic expressions.
Correct answer
D. A single gene affecting multiple phenotypic expressions.
Step-by-step solution
A single gene can exhibit multiple phenotypic expression in an organism. Such a gene is called a pleiotropic gene. The underlying mechanism of the pleiotropy is the effect of a gene (and its alleles) on the metabolic pathways which contribute towards different phenotypes.
Some common example of pleiotropy is phenylketonuria, a disease is caused by mutation in the gene that codes for the enzyme phenyl alanine hydroxylase (single gene mutation). This results into the phenotypic expression characterised by mental retardation and a reduction in hair and skin pigmentation.