For many species, including humans, matings occur among a restricted pool of partners. In humans, restrictions on the choice of partners are culturally determined and frequently are the result of homophily, namely, contacts among individuals that are similar on some dimension. Marcus Feldman, Stanford University, discusses how the dimension may itself be culturally transmitted, and its transmission may affect the transmission of other characters, which may be genetically determined, but have nothing to do with the dimension on which the mating choice is based. Socioeconomic choice of consanguineous marriage is an example; it has important consequences for genetic variation in many populations around the world. Series: "CARTA - Center for Academic Research and Training in Anthropogeny" [Science] [Show ID: 24113]