heritabilitást

Heritabilitást, or heritability in Hungarian usage, refers to the proportion of phenotypic variation in a trait that can be attributed to genetic differences among individuals within a particular population at a given time and environment. In genetics, this quantity is often denoted by h^2 and ranges from 0 to 1 (or 0% to 100%). It is the ratio of genetic variance to total phenotypic variance: h^2 = Vg / Vp, where Vp = Vg + Ve + Vge (and measurement error). There are different concepts: broad-sense heritability (H^2) includes all genetic effects: additive, dominance, and epistasis; narrow-sense heritability (h^2) includes only additive effects, which are most relevant for selection in breeding.

Heritability is context-dependent. It depends on the population and environment studied; a trait can have high heritability in one setting and low in another if environmental differences are large or allele frequencies differ. It does not indicate the degree to which a trait is genetically determined in an individual; even a highly heritable trait can respond to environmental changes or interventions. It also does not reveal the specific genes involved; it summarizes genetic influence.

Estimating heritability uses twin or family studies, adoption studies, or molecular methods such as SNP-based estimates. Applications include plant and animal breeding, and studies of human traits and diseases, but estimates must be interpreted carefully to avoid misattributing causality.