Introduction to Quantitative Genetics

Heritability

The general term that describes the proportion of the genetic variance to the total variance is heritability.

Boad-sense heritability is the ratio of total genetic variance to total phenotypic variance.

H2 = VG/VP

Narow-sense heritability is the ratio of additive genetic variance to the total phenotypic variance.

h2 = VA/VP

Important points about heritability

  1. The heritability estimate is specific to the population and environment you are analyzing.
  2. The estimate is a population, not an individual parameter.
  3. Heritability does not indicate the degree to which a trait is genetic, it measures the proportion of the phenotypic variance that is the result of genetic factors.