Molecular genetic methods of heritability estimation have tended to produce lower estimates than classical twin studies due to modern SNP arrays not capturing the influence of certain types of variants (e.g., rare variants or repeat polymorphsisms), though some have suggested it is because twin studies overestimate heritability. A 2016 study determined that the assumption that the prenatal environment of twins was equal was largely tenable.. Researchers continue to debate whether or not the equal environment assumption is valid.Fosse, Roar, Jay Joseph, and Ken Richardson. "A critical assessment of the equal-environment assumption of the twin method for schizophrenia." Frontiers in psychiatry 6 (2015): 62.Joseph, Jay. The trouble with twin studies: A reassessment of twin research in the social and behavioral sciences. Routledge, 2014.
Molecular genetic methods of heritability estimation have tended to produce lower estimates than classical twin studies due to modern SNP arrays not capturing the influence of certain types of variants (e.g., rare variants or repeat polymorphsisms), though some have suggested it is because twin studies overestimate heritability. A 2016 study determined that the assumption that the prenatal environment of twins was equal was largely tenable.. Researchers continue to debate whether or not the equal environment assumption is valid.Fosse, Roar, Jay Joseph, and Ken Richardson. "A critical assessment of the equal-environment assumption of the twin method for schizophrenia." Frontiers in psychiatry 6 (2015): 62.Joseph, Jay. The trouble with twin studies: A reassessment of twin research in the social and behavioral sciences. Routledge, 2014.