Least Reliable Heritability Estimation
Least reliable method of heritability estimation is-
- Half-sib correlation method
- Full sib correlation — Correct Answer
- Intra-class regression method
- BLUP
Explanation:
Correct Answer: Full sib correlation
The Full-sib correlation method is the least reliable for estimating heritability. Full siblings share not only ½VA (additive genetic variance) but also ¼VD (dominance variance) and a large VEC (common environmental variance — shared dam, shared prenatal/postnatal environment). This severely inflates the estimated h².
Why Full-Sib Method Overestimates h²
- The genetic covariance of full sibs = ½VA + ¼VD + VEC
- Only ½VA should contribute to h²; the extra ¼VD and VEC inflate the estimate
- Example: if t (intraclass correlation) for full sibs = 0.30, h² = 2 × 0.30 = 0.60, but the true h² may only be 0.30 because VD and VEC inflated t
Reliability Ranking of h² Estimation Methods
| Rank | Method | Reason |
|---|---|---|
| 1 (Best) | Half-sib correlation (paternal) | Only ¼VA shared; no common environment bias |
| 2 | Intra-sire regression | ½VA; avoids assortative mating |
| 3 | Dam-daughter regression | ½VA; may include maternal effects |
| 4 (Least reliable) | Full-sib correlation | Inflated by VD and VEC |
📚 About this Topic — Animal Genetics & Breeding
This multiple choice question is from Animal Genetics & Breeding, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Genetics & Breeding to strengthen your preparation.
