Genetic factors are often responsible for variation within populations, while environmental factors are usually responsible for variation between populations, per Rose’s causes-of-cases vs causes-of-incidence distinction.

Evidence

Sick individuals and sick populations (International Journal of Epidemiology / Oxford Academic)

Categorization

  • corroborated: 5 independent passages support this claim
  • XREF: connects to: Intelligence is malleable and shaped by environment, not fixed by heredity — Harriet A. Washington, A Terrible Thing to Waste, 54; Lewontin’s corn thought experiment shows within-group phenotypic variation can be genetic while between-group variation is environmental, since within-group heritability is irrelevant for determining causes of among-group differences. — Heritability within groups is uninformative about differences among groups: Cases from behavioral, evolutionary, and statistical genetics