Question

When a single gene influences more than one trait it is called:

• A. pleiotropy
• B. pseudodominance
• C. epistasis
• D. none of these

Answer 1

The correct option is A

pleiotropy

The correct option is A

Explanation of the correct option:

1. Pleiotropy is defined as the expression of multiple traits by a single gene. eg. of Pleiotropy is phenylketonuria.
2. It is a genetic disorder caused by the low metabolism of amino acid phenylalanine in body cells.
3. Mendel’s observations were also based on the result of pleiotropy which is a phenomenon wherein an individual gene also plays its role in multiple phenotypic traits.
   

Explanation of the incorrect option:

Option B:

1. The sudden appearance of a recessive phenotype in a pedigree is due to the deletion of the masking dominant gene.
2. The phenomenon in which a recessive allele shows itself in phenotype when only one copy of the allele is present, as in hemizygous alleles or in deletion heterozygotes is called pseudodominance.

Option C:

Epistasis is a circumstance where the expression of one gene is modified (e.g., masked, inhibited, or suppressed) by the expression of one or more genes.

Final answer: When a single gene influences more than one trait it is called pleiotropy.