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 express themselves fully
(d)	Polygenic inheritance	(iv)	A single gene influences many characters

• A. a - ii; b - iii; c - iv; d - i
• B. a - ii; b - i; c - iv; d - iii
• C. a - iv; b - i; c - ii; d - iii
• D. a - iv; b - iii; c - i; d - ii

Answer 1

The Correct Option is A

To match the terms in Column-I with their corresponding descriptions in Column-II, let's analyze each term and its definition:

1. Dominance: This genetic principle refers to the scenario in a heterozygous organism where only one allele expresses itself. In simpler terms, the dominant allele masks the recessive one. Therefore, Dominance corresponds to (ii) In a heterozygous organism only one allele expresses itself.
2. Codominance: This occurs when both alleles in a heterozygous organism are fully expressed, leading to a phenotype that shows both traits clearly. Thus, Codominance matches with (iii) In a heterozygous organism both alleles express themselves fully.
3. Pleiotropy: In this case, a single gene affects multiple phenotypic traits. Hence, Pleiotropy corresponds to (iv) A single gene influences many characters.
4. Polygenic Inheritance: This is when a single trait is governed by multiple genes, often resulting in a continuous range of possible phenotypes (e.g., height, skin color). Therefore, Polygenic inheritance matches with (i) Many genes govern a single character.

Based on the above analyses, the correct pairings are:

Option: a - ii; b - iii; c - iv; d - i

This option correctly aligns each term with its definition in genetics.