Each Sim has three traits and an aspiration containing its own hidden trait. The unibrow is a recessive genetic trait. It is also inherited as an autosomal recessive trait in Texel sheep. Often different genes can interact in a way that influences the same trait. We are interested in deciding if the characteristic is inherited as a simple Mendelian trait. There are social and political implications to this personality trait. Brachydactyly is an inherited, usually dominant trait. There is renewed interest in studying sadism as a personality trait. It is the single most indicative distinguishing trait of totalitarian regimes. Inbreeding also helps to ascertain the type of gene action affecting a trait. Therefore he called this biological trait dominant. He did further experiments that showed each trait is separately inherited. Hairless Xolos are the dominant expression of the heterozygous Hh hairless trait. Females heterozygous for the trait are unaffected. All these models assume a single underling latent trait or ability.