Heritability
Definition
The proportion of variation in a trait within a population that is attributable to genetic differences between individuals. A heritability estimate applies to a specific population in a specific environment; it does not mean a trait is genetically fixed or unresponsive to environmental change.
- Scale
- Expressed as a proportion, 0 to 1 (or 0% to 100%)
- Scope
- Applies to a specific population in a specific environment
- Field
- Quantitative and behavioural genetics
- Common misuse
- Mistaken for a fixed, individual-level genetic determination
Common questions
Does a heritability of 50% mean half of a person's trait is caused by genes?+
No. Heritability is a population-level statistic describing how much of the variation between individuals tracks genetic differences under current conditions. It says nothing about the causal mix inside any one person, and it cannot be applied to an individual case.
Why does heritability change between populations or environments?+
The estimate depends on how much environmental variation exists in the sample studied. If environments become more uniform, a larger share of remaining variation is attributable to genetics and heritability rises, even though the trait's biology has not changed.
Related terms
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- Concordance Rate
- In twin studies, the proportion of twin pairs in which both twins share a given trait or behaviour. Higher concordance in monozygotic...
- Gene-Environment Interaction (GxE)
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- Prefrontal Cortex (PFC)
- The frontal brain region responsible for impulse control, planning, and decision-making. Reduced grey matter volume and lower activation in the PFC have...