The dopamine transporter gene (SLC6A3) is relevant to aggression and other behavioral changes across species. SLC6A3 encodes a protein responsible for regulation of signal amplitude and duration in dopaminergic synapses in the brain. Research by Drs. Lisa Lit, Anita Oberbauer and colleagues at the Department of Animal Science, University of California-Davis identified two polymorphisms in the SLC6A3 gene associated with owner reports of seizure, glazing over, behaviors, episodic biting behaviors, and general loss of clarity in the Belgian Malinois. These polymorphisms have further been associated with increased aversive treatment of dogs by handlers, and increased stress in dogs in response to handlers. For dogs whose owners reported these behaviors, these closely linked polymorphisms were more likely to be present. One of these polymorphisms, PolyA(22), is also associated with increased activity in both novel and familiar environments. Among the two polymorphisms, PolyA(22) is a better predictor of behavior. To date, an association between the polymorphism(s) and behavior/seizure has not been confirmed in breeds other than the Belgian Malinois. Findings were obtained using primarily working lines of Belgian Malinois. Because of the complex nature of behavior, it is possible that environmental factors such as stress may contribute to the expression of adverse owner-reported behaviors. [From US Davis website]