Do the dimensions of the temperament and character inventory map a simple genetic architecture? Evidence from molecular genetics and factor analysis

Objective: It has been reported that the human temperament dimensions of no velty seeking and harm avoidance are associated with polymorphisms in the D -4 dopamine receptor gene (D4DR) and the serotonin-transporter-linked promo ter region (5-HTTLPR), respectively. Although these findings are consistent with Cloninger's hypothesized psychobiological model of temperament and ch aracter, many studies failed to replicate these findings. In the present st udy the authors tested whether the psychobiological model taps the genetic architecture of personality by exploring associations between these candida te genes and the dimensions of the Temperament and Character Inventory and by examining its phenotypic structure. Method: Of the 946 male and female participants in the Baltimore Longitudin al Study of Aging to whom the Temperament and Character Inventory was admin istered, 587 were genotyped for a polymorphism with a 48-base-pair repeat i n the D4DR gene and 425 were genotyped for a 44-base-pair insertion or dele tion in the 5-HTTLPR polymorphism. Results: There was no significant association between D4DR polymorphisms an d novelty seeking. The authors also failed to find an association between 5 -HTTLPR polymorphisms and harm avoidance. The factor structure of the Tempe rament and Character Inventory did not reveal the hypothesized phenotypic s tructure. Conclusions: This investigation produced no support for the temperament-cha racter model at either the biological or psychological level.