Question

in research examining the contribution of genes to addiction, the neurotransmitter ______ appears to be involved.

Explanation:

In research on genes and addiction, dopamine is a key neurotransmitter involved. Addiction often relates to the brain's reward system, and dopamine plays a central role in reward, motivation, and pleasure pathways. Genetic factors can influence dopamine function (e.g., receptor availability, synthesis, or reuptake), which impacts addiction vulnerability. Other neurotransmitters like serotonin or GABA may be involved, but dopamine is most strongly associated with the reward - related aspects of addiction linked to genetic contributions.

Answer:

dopamine