The Heritability Gap: Twin Studies vs. Genomics
Since the 1970s, twin studies have suggested high heritability for many behavioral traits, with IQ estimated at around 60% genetic. However, Genome-Wide Association Studies (GWAS) have struggled to find these genes, leading to the "heritability gap." Recent research suggests GWAS predictive power may be inflated due to population stratification, assortative mating, and genetic nurture. New methods like Sib-Regression and RDR offer alternative approaches to estimate heritability, yielding results that differ from twin studies. Debate continues on the true heritability and reasons for discrepancies between methods; some argue twin studies overestimate heritability, while others point to GWAS's neglect of rare variants and gene interactions. Many mysteries remain, demanding further research.