What is heritability in the narrow sense?

What is heritability in the narrow sense?

• A. The % of the phenotype due to transmittable gene effects.
• B. The % due to environment.
• C. The influence of management.
• D. The proportion of phenotype due to non-transmissible factors.

Answer: (A)

Narrow-sense heritability measures how much of the observed variation among individuals is due to additive genetic effects that are transmitted from parents to offspring. It is the proportion VA/VP, where VA is additive genetic variance and VP is total phenotypic variance. Additive effects are the gene actions that parents pass on in predictable amounts to their offspring, shaping resemblance between generations. Environment and non-additive genetic interactions (like dominance or epistasis) contribute to phenotype but are not counted in this narrow sense. The option describing the percent of the phenotype due to transmittable gene effects captures this idea most directly.

Narrow-sense heritability measures how much of the observed variation among individuals is due to additive genetic effects that are transmitted from parents to offspring. It is the proportion VA/VP, where VA is additive genetic variance and VP is total phenotypic variance. Additive effects are the gene actions that parents pass on in predictable amounts to their offspring, shaping resemblance between generations. Environment and non-additive genetic interactions (like dominance or epistasis) contribute to phenotype but are not counted in this narrow sense. The option describing the percent of the phenotype due to transmittable gene effects captures this idea most directly.