Final answer:
The 5HTT gene codes for serotonin reuptake, while DRD4 is associated with the trait of novelty seeking. These genes are studied in relation to their effects on neurotransmission and behavior, and their polymorphisms may interact with environmental factors to influence personality and mental health.
Step-by-step explanation:
The genes 5HTT and DRD4 are commonly studied in the context of psychiatric genetics and behavioural neuroscience. The correct answer is that 5HTT codes for serotonin reuptake and DRD4 is studied in relation to novelty seeking. Specifically, 5HTT is responsible for serotonin transporter function, which affects the movement of serotonin across neural synapses, while DRD4 pertains to the dopamine D4 receptor, which has implications in dopamine signaling pathways and has been associated with personality traits like novelty seeking.
Research has shown that polymorphisms in these genes may interact with environmental factors to influence an individual's predisposition to certain behaviors or mental health conditions, such as depression (Caspi et al., 2003) and posttraumatic stress disorder (Xie et al., 2009). Therefore, the correct answer to the question about what these genes code for and what personality traits they are studied in relation with is b) 5HTT - serotonin reuptake; DRD4 - novelty seeking.