What does heritability measure?

Heritability specifically measures the proportion of variation in a trait within a population that can be attributed to genetic differences among individuals. This concept is crucial in understanding how genetic and environmental factors contribute to individual differences.

For example, a high heritability estimate for a trait suggests that genetic factors play a significant role in the observed variations of that trait within the population studied. It is important to note that heritability does not refer to the degree of the trait's genetic influence on an individual, but rather the extent to which genetic factors contribute to differences among individuals within a specific environment or population.

In contrast, the other options focus on aspects that are not aligned with the precise definition of heritability. Heritability is not about environmental factors alone, inheritance across generations, or similarities within family genetics but specifically about the genetic contribution to variation in traits across a population.