What term refers to the proportion of variation among individuals that is due to genes, noting that it can vary by population and environment?

• A. Genotype
• B. Phenotype
• C. Mutation rate
• D. Heritability

Answer: (D)

Heritability is the proportion of variation among individuals that is due to genetic differences, and it can vary by population and environment. It’s a population-level statistic, not a measure for any one person, and it is estimated by partitioning observed variation into genetic and environmental components across relatives or groups. Genotype refers to the genetic makeup of an individual, while phenotype is the observable trait resulting from both genes and environment. Mutation rate describes how often new genetic changes occur, not how much of a trait’s variation is due to genes. Because heritability depends on the context, the same trait can have different values in different populations or environments due to gene–environment interactions. For example, height often shows high heritability in populations with uniform nutrition but can appear lower when nutritional variation is large. In short, heritability captures how much genetic differences contribute to variation in a trait across a specific group and setting.