A research team examines concordance rates for a mood disorder across 800 monozygotic and 800 dizygotic twin pairs raised together. They report concordance of 0.55 for monozygotic pairs and 0.22 for dizygotic pairs. The investigators apply behavioral genetic models to estimate heritability while acknowledging shared environment as a covariate.
The pattern of concordance rates most directly suggests which inference?
- A
Concordance rates prove a single-gene cause
- B
Environmental factors play no role in the disorder
- Ccheck_circle
Genetic factors contribute substantially to the disorder's etiology
- D
The disorder is fully determined by genetics
Explanation
Higher MZ than DZ concordance indicates a genetic contribution. However, MZ concordance below 1.0 shows environmental factors also matter.