NEET 2026
- Exam
- NEET
- Year
- 2026
- Subject
- Biology
- Chapter
- Chapter
NEET 2026 · Biology · Chapter
A genetic disorder in humans is caused by a mutation in the gene...
A genetic disorder in humans is caused by a mutation in the gene that codes for the enzyme phenylalanine hydroxylase. This single gene mutation manifests in multiple phenotypic expressions, including mental retardation and a reduction in hair and skin pigmentation. This illustrates the phenomenon of:
Options
- APolygenic inheritance
- BMultiple allelism
- CPleiotropy
- DCodominance
Correct answer
C. Pleiotropy
Step-by-step solution
The genetic disorder described is Phenylketonuria (PKU), which is caused by a mutation in the gene coding for the enzyme phenylalanine hydroxylase.
This single gene mutation leads to multiple phenotypic expressions, such as mental retardation and a reduction in hair and skin pigmentation.
The phenomenon where a single gene exhibits multiple phenotypic expressions is known as pleiotropy.
Answer: Pleiotropy
This single gene mutation leads to multiple phenotypic expressions, such as mental retardation and a reduction in hair and skin pigmentation.
The phenomenon where a single gene exhibits multiple phenotypic expressions is known as pleiotropy.
Answer: Pleiotropy