Which term refers to the proportion of phenotypic variation that can be attributed to genetic factors?

Which term refers to the proportion of phenotypic variation that can be attributed to genetic factors?

• A. Directional selection
• B. Heritability
• C. Founder effect
• D. Genetic drift

Answer: (B)

Heritability is the proportion of phenotypic variation in a population that is due to genetic differences among individuals. It is usually denoted as h^2 and can be thought of as V_A or V_G divided by the total phenotypic variance V_P (V_P = V_G + V_E). This means that when heritability is high, most of the observed differences in the trait across individuals come from genetics; when it is low, environmental factors play a larger role. Remember, heritability is a population and context-specific measure, not a statement about a trait in a single person, and it does not imply that a trait is immutable or determined solely by genes. The other options describe evolutionary processes or population events (directional selection, founder effect, genetic drift) rather than a measure of genetic contribution to variation.

Heritability is the proportion of phenotypic variation in a population that is due to genetic differences among individuals. It is usually denoted as h^2 and can be thought of as V_A or V_G divided by the total phenotypic variance V_P (V_P = V_G + V_E). This means that when heritability is high, most of the observed differences in the trait across individuals come from genetics; when it is low, environmental factors play a larger role. Remember, heritability is a population and context-specific measure, not a statement about a trait in a single person, and it does not imply that a trait is immutable or determined solely by genes. The other options describe evolutionary processes or population events (directional selection, founder effect, genetic drift) rather than a measure of genetic contribution to variation.