Dopamine transporter (DAT) gene (SLC6A3) encodes protein that regulates the synthetic levels of dopamine in the brain and leads to addictive behavior.[52] It is expected that recent advances in molecular biology, including the completion of draft sequence of the human genome may help in identifying gene markers that predict a heightened risk of using tobacco to increase our understanding of nicotine dependence.[53]. Here, SLC6A3 is linked to nicotine dependence.