What is heritability in the broad sense?

What is heritability in the broad sense?

• A. The percentage of the phenotype determined by environment.
• B. The average age at which a trait is expressed.
• C. The percentage of the phenotype due to genetics.
• D. The likelihood that offspring resemble parents.

Answer: (C)

Heritability in the broad sense tells you what fraction of the differences you see in a trait among individuals in a population come from genetic differences, not the environment. It’s expressed as H^2 = V_G / V_P, where V_G includes all genetic variance (additive, dominance, and epistatic), and V_P is the total phenotypic variance. So if genetics accounts for a portion of the variation, that portion is the broad-sense heritability. This is a population-level measure and does not predict what will happen in a single individual, nor does it say the trait is purely genetic. It’s not about the average age of trait expression, and while offspring resemblance is related to genetics, heritability is about the proportion of variation across the population, not a simple likelihood of resemblance.

Heritability in the broad sense tells you what fraction of the differences you see in a trait among individuals in a population come from genetic differences, not the environment. It’s expressed as H^2 = V_G / V_P, where V_G includes all genetic variance (additive, dominance, and epistatic), and V_P is the total phenotypic variance. So if genetics accounts for a portion of the variation, that portion is the broad-sense heritability. This is a population-level measure and does not predict what will happen in a single individual, nor does it say the trait is purely genetic. It’s not about the average age of trait expression, and while offspring resemblance is related to genetics, heritability is about the proportion of variation across the population, not a simple likelihood of resemblance.