We developed a method for estimating narrow sense heritability from unrelated individuals by leveraging the two ancestral genomes in recently admixed populations, such as African Americans. We used a population genetic approach to derive the relationship between heritability and variation in local ancestry in admixed populations. Theory and simulations confirm that under an infinitesimal phenotypic model our approach produces unbiased estimates of heritability. Since the individuals are distantly related, our approach will not produce heritability estimates inflated by epistasis, gene environment interactions, or shared environmental effects.
