Heritability estimates for the TPQ/TCI scales range from approximately 30% to 60% (Gillespie, Cloninger, Heath, & Martin, 2003; Gillespie, Johnstone, Boyce, Heath, & Martin, 2001; Heath, Cloninger, & Martin, 1994; Heiman, Stallings, Hofer, & Hewitt, 2003; Keller, et al., 2005), consistent with heritability estimates for other personality scales such as the Big Five (Jang, Livesley, & Vernon, 1996) and Eysenck’s personality dimensions (Keller, et al., 2005; Zietsch, Verweij, Bailey, Wright, & Martin, 2010). Despite these substantial genetic influences, identifying the specific genetic variants underlying individual differences on TPQ/TCI and other personality scales has proved difficult.
