Representative agarose gel of 5HTTLPR PCR fragments from Genomic DNA. Representative 2% agarose gel showing fragments obtained from a PCR using genomic DNA isolated from Vermont Family Study spit wads and primers specific for 5HTTLPR polymorphism. Lane 1 contains 50 bp DNA ladder (Fisher Bioreagents), with a bold reference band of 400 bp. Lane 2 is a positive control sample with known S/L genotype. Lanes 3–14 show fragments generated from 12 samples using genomic DNA extracted from spit wads as template for 5HTTLPR PCR reaction. 12.5 μl of the 25 μl PCR reaction was mixed with 2 ul of 6X agarose DNA loading dye (Fisher Bioreagents) prior to loading the gel.