Question

Student to attempt either option-(A) or (B):
(A) Write the features a molecule should have to act as a genetic material. In the light of the above features, evaluate and justify the suitability of the molecule that is preferred as an ideal genetic material. 
OR 
(B) Differentiate between the following:

• [(i)] Polygenic Inheritance and Pleiotropy
• [(ii)] Dominance, Codominance and Incomplete dominance

Hint:

DNA is preferred as genetic material because of its stability, ability to replicate, and storage of vast genetic information. Understanding dominance types helps decode trait expression patterns.

Answer 1

(A) Features of an ideal genetic material:

• Should be able to replicate accurately.
• Must store all genetic information.
• Should express the information as phenotypes.
• Should permit occasional mutations for variation and evolution.
• Must be chemically and structurally stable.

Justification: DNA is considered the most suitable genetic material because it meets all the above criteria. It replicates semi-conservatively, is stable under physiological conditions, and carries information through sequences of nitrogenous bases. It also undergoes mutations at a low rate, allowing genetic variation without compromising integrity. 
OR 
(B)

(i)

Polygenic Inheritance	Pleiotropy
A single trait is controlled by multiple genes.	A single gene influences multiple traits.
Example: Skin color in humans.	Example: Sickle cell anemia gene affects multiple organs.

(ii)

Dominance	Codominance	Incomplete Dominance
One allele masks the effect of another.	Both alleles express equally in the heterozygote.	The heterozygote shows an intermediate phenotype.
Example: Tall (T) dominant over dwarf (t) in pea.	Example: AB blood group.	Example: Flower color in snapdragon.