Question

The most reliable procedure of heritability estimation is

• A. Full sib correlation
• B. Half sib correlation
• C. Regression of offspring on dam
• D. Intra-sire regression of offspring on dam

Hint:

Heritability Reliability Ranking: 1. INTRA-SIRE REGRESSION OF OFFSPRING ON DAM (Most reliable, no maternal/sire bias) $>$ 2. Paternal Half-Sib Analysis $>$ 3. Full-Sib Analysis (Biased by $V_D$ and $V_{Ec}$).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Heritability estimation methodologies: intra-sire regression of offspring on dam removes confounding paternal environmental effects and non-random assortative mating biases.
Key Formula or Approach:
\[ h^2 = 2 \cdot b_{\text{Offspring, Dam (Intra-Sire)}} \quad [\text{Free from Maternal Common Environment \& Assortative Mating Bias}] \]

Step 2: Detailed Explanation:
Evaluating heritability ($h^2$) estimation methods in quantitative genetics:
1. Full-Sib Correlation: Inflated by dominance variance ($1/4\; V_D$) and common maternal environmental variance ($V_{Ec}$).
2. Half-Sib Correlation: Requires large paternal family sizes and assumes random mating.
3. Intra-Sire Regression of Offspring on Dam (D): By computing regression within sire groups:
- It completely removes all confounding differences between sires (sire environmental and genetic effects).
- It is completely free from non-random assortative mating biases.
- It eliminates common environmental effects ($V_{Ec}$) that inflate full-sib methods.
- Hence, it is universally recognized as the most statistically robust and reliable procedure for estimating narrow-sense heritability ($h^2 = 2 b_{\text{OD}}$).

Step 3: Final Answer:
Hence, the most reliable procedure is Intra-sire regression of offspring on dam, corresponding to option (D).