What term describes the proportion of total phenotypic variability observed for a trait that can be ascribed to genetic factors?

What term describes the proportion of total phenotypic variability observed for a trait that can be ascribed to genetic factors?

• A. Twin method
• B. Heritability
• C. Gene flow
• D. Directional selection

Answer: (B)

Heritability is the proportion of observed phenotypic variation in a trait that comes from genetic differences among individuals in a given population and environment. In quantitative genetics, total phenotypic variance (Vp) is split into genetic variance (Vg) and environmental variance (Ve), with heritability often expressed as the ratio Vg/Vp (broad-sense) or Va/Vp (narrow-sense, using additive genetic variance). This means heritability reflects how much of the differences you see in the trait across individuals are due to genetics, not to differences in environment, and it can vary between populations and environments. It's not a description of a study method or an evolutionary process. For example, the twin method is a design used to estimate heritability, while gene flow refers to the movement of genes between populations, and directional selection describes a process that shifts a trait’s mean over generations.

Heritability is the proportion of observed phenotypic variation in a trait that comes from genetic differences among individuals in a given population and environment. In quantitative genetics, total phenotypic variance (Vp) is split into genetic variance (Vg) and environmental variance (Ve), with heritability often expressed as the ratio Vg/Vp (broad-sense) or Va/Vp (narrow-sense, using additive genetic variance). This means heritability reflects how much of the differences you see in the trait across individuals are due to genetics, not to differences in environment, and it can vary between populations and environments.

It's not a description of a study method or an evolutionary process. For example, the twin method is a design used to estimate heritability, while gene flow refers to the movement of genes between populations, and directional selection describes a process that shifts a trait’s mean over generations.