heritable

Heritable is a biological term used to describe a trait that can be passed from parents to offspring through genetic information. In population genetics, heritability refers to a statistic that estimates how much of the variation in a trait observed in a population is due to genetic differences among individuals, rather than to environmental factors or measurement error. Heritability is a property of populations, not of individuals, and it can differ across populations and environments.

Heritability is decomposed into components. Narrow-sense heritability estimates the proportion of phenotypic variance due to additive genetic effects, while broad-sense heritability includes all genetic contributions, including dominance and epistasis. Methods to estimate heritability include twin and family studies, analysis of adoptees, and genome-wide approaches that use single-nucleotide polymorphisms.

Examples of heritable traits range from highly heritable features such as eye color to more complex ones like height or risk for certain diseases, which exhibit substantial but incomplete genetic influence. Even highly heritable traits can be strongly affected by environment or show gene–environment interactions.

A key caveat is that a trait’s heritability is not a fixed attribute of the trait. It depends on the population and environmental context, and a trait that is highly heritable in one setting may be less so in another. Conversely, low heritability does not imply the absence of genetic influence.