Question

Match the terms in Column I with their description in Column II and choose the correct option:

Column I	Column II
(a) Dominance	(i) Many genes govern a single character
(b) Codominance	(ii) In a heterozygous organism only one allele expresses itself
(c) Pleiotropy	(iii) In a heterozygous organism both alleles expresses themselves fully
(d) Polygenic inheritance	(iv) A single gene influences many characters

• A. (iv), (i), (ii), (iii)
• B. (iv), (iii), (i), (ii)
• C. (ii), (i), (iv), (iii)
• D. (ii), (iii), (iv), (i)

Answer 1

Answer: (D)

Dominance refers to the ability of one allele to mask the expression of another allele of same gene present together in a heterozygous individual.

When both recessive and dominant traits are expressed in a heterozygous genotype, it is codominance. This means that none of the factors is recessive but both can express themselves irrespective of their presence in homozygous or heterozygous condition.

Pleiotropy is the condition where a gene has its own independent effect but also modifies the expression of a completely different gene quantitatively.

A polygenic trait is the one that is governed by more than one gene were dominant allele of each gene express only a part of trait and the full trait is expressed only in the presence of dominant alleles of all multiple genes.

The correct answer is B.