Question

Match List-I with List-II
List-I (Genetic principle):
(A) Sex influenced
(B) Sex limited
(C) Sex linked
(D) High heritability
List-II (Characteristics):
(I) Egg production
(II) Hen feathering
(III) Slow feathering
(IV) Body weight in poultry
Choose the correct answer from the options given below:

• (A) - (I), (B) - (II), (C) - (III), (D) - (IV)
• (A) - (IV), (B) - (I), (C) - (III), (D) - (II)
• (A) - (III), (B) - (IV), (C) - (I), (D) - (II)
• (A) - (II), (B) - (I), (C) - (III), (D) - (IV)

Hint:

To easily distinguish sex-linked from sex-limited traits:
- Sex-linked traits are on the sex chromosomes (Z/W) and show criss-cross inheritance.
- Sex-limited traits are on autosomes but are expressed in only one sex (e.g., egg laying in hens, milk yield in cows).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Traits in poultry are governed by different modes of inheritance and genetic parameters, which influence how they are expressed and selected for in breeding programs.
Detailed Explanation:
Let us match each genetic principle with its corresponding characteristic:
- (A) Sex influenced: These traits are controlled by autosomal genes, but their phenotypic expression is modified by the sex hormones of the individual.
A classic example is hen feathering (II) in breeds like Campines and Sebrights.
The dominant allele (Hf) causes males to grow hen-like plumage instead of cock-like plumage because the feathers are highly sensitive to estrogens.
- (B) Sex limited: These autosomal traits are expressed in only one of the sexes due to anatomical or physiological differences.
Egg production (I) is a classic example, as the genes are carried by both sexes but are expressed only in females.
- (C) Sex linked: These genes are located on the sex chromosomes (Z and W in birds).
Slow feathering (III) is controlled by a dominant gene (K) on the Z chromosome.
This trait is widely used in commercial hatcheries for feather-sexing day-old chicks.
- (D) High heritability: Body weight in poultry (IV) is a quantitative trait with a high narrow-sense heritability (\(h^2 > 0.40\)), allowing for rapid progress through mass selection.
Combining these individual matches:
\[ (A) \rightarrow (II), \quad (B) \rightarrow (I), \quad (C) \rightarrow (III), \quad (D) \rightarrow (IV) \] This matches option (D).

Step 2: Final Answer:
The correct match is (A) - (II), (B) - (I), (C) - (III), (D) - (IV).