Using a polygenic score in a family design to understand genetic influences on musicality

To further our understanding of the genetics of musicality, we explored associations between a polygenic score for self-reported beat synchronization ability (PGS_rhythm) and objectively measured rhythm discrimination, as well as other validated music skills and music-related traits. Using family data, we were able to further explore potential pathways of direct genetic, indirect genetic (through passive gene-environment correlation) and confounding effects (such as population structure and assortative mating). In 5648 Swedish twins, we found PGS_rhythm to predict not only rhythm discrimination, but also melody and pitch discrimination (betas between 0.11 and 0.16, p < 0.001), as well as other music-related outcomes (p < 0.05). In contrast, PGS_rhythm was not associated with control phenotypes not directly related to music. Associations did not deteriorate within families (N = 243), implying that indirect genetic or confounding effects did not inflate PGS_rhythm effects. A correlation (r = 0.05, p < 0.001) between musical enrichment of the family childhood environment and individuals' PGS_rhythm, suggests gene-environment correlation. We conclude that the PGS_rhythm captures individuals' general genetic musical propensity, affecting musical behavior more likely direct than through indirect or confounding effects.