Question

Match the columns I and II.

Column I	Column II
Pleiotropic gene	Both allele express equally
Codominance	Change in nucleotide
Epistasis	One gene shows multiple phenotypic expression
Mutation	Non - allelic gene inheritance

• A. A-1, B-2, C-3, D-4
• B. A-2, B-3, C-4, D-1
• C. A-3, B-1, C-4, D-2
• D. A-1, B-3, C-4, D-2

Answer 1

The correct option is C A-3, B-1, C-4, D-2

A gene that exhibits multiple phenotypic expressions is called a pleiotrophic gene. This is seen in case of the disease phenylketonuria, in which the gene for enzyme phenyl alanine hydroxylase is mutated. This is expressed as changes in skin pigmentation, mental retardness and reduction in hair.

In case of codominance, both the alleles contribute to phenotypic expression.
e.g: blood type in humans

Epistasis is the phenomenon in which multiple non-allelic genes contribute to one phenotypic expression.
e.g: eye colour is determined by 8 different genes

Mutation is a phenomenon which results in alteration of nucleotide sequences and which in turn results in changes in the genotype and the phenotype of an organism. It contributes to variations in genotype.