For the DAT VNTR assay at least 2 of each 9,9 VNTR and 10,10 VNTR samples were sequenced as follows: after electrophoresis on a 2.0% agarose gel, samples were isolated (QIAquick® Gel Extraction Kit, QIAGEN Sciences) and sequenced in both directions using an ABI377 automated sequencer at the MUSC Nucleic Acid Analysis Facility (Charleston, SC). Results of the sequence were checked against published sequences for the specific SCL3R6 VNTR sequences. Once confirmed, these samples were used as positive controls for all subsequent genotyping to identify the appropriate bands on agarose gels indicating DAT genotypes of 9,9: 9,10: or 10,10 VNTR’s.
