The application of our approach to two large cohorts of African Americans revealed a difference between previously published family-based estimates of the heritability of height and BMI and our estimates. This suggests that there is a significant contribution of non-additive genetic effects or shared environmental effects that differ between MZ and DZ twins. The future application of our method to large-scale studies of African Americans will both provide a mechanism of estimating the total narrow sense heritability of phenotypes as well as determining the genetic architecture of complex phenotypes.
