Narrow vs Broad Sense Heritability
Heritability in the narrow sense is:
- Always less than or equal to broad sense heritability — Correct Answer
- Always greater than broad sense heritability
- Always less than broad sense heritability
- None of the above
Explanation:
Correct Answer: Always less than or equal to broad sense heritability
Heritability in narrow sense (h²N) ≤ broad sense heritability (H²B) always, because:
- h²N = VA / VP (only additive variance)
- H²B = VG / VP = (VA + VD + VI) / VP
Since VG = VA + VD + VI and VD and VI are always ≥ 0, we get H²B ≥ h²N.
Components of Variance
| Variance | Formula | Components |
|---|---|---|
| Phenotypic (VP) | VG + VE | Total observable variation |
| Genotypic (VG) | VA + VD + VI | All genetic sources |
| h²N | VA/VP | Additive only — used in selection |
| H²B | VG/VP | All genetic — always ≥ h²N |
- Repeatability (r) is the upper limit of H²B: r ≥ H²B ≥ h²N
📚 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.
