The inception of powerful sequencing technologies has allowed the scientific community to share and access vast amounts of genomic sequences through public databases. These data are a useful resource for studying genetic variation. Here, we describe the process that allowed for the identification of a VNTR (Variable Number of Tandem Repeats) within the DAT1 gene (SLC6A3). Given the gene’s well-established role in addictive behavior, we then discuss the possible role of this VNTR in addiction.