Organization of SERT and location of polymorphisms. A. SERT gene organization showing coding (orange) exons and non-coding and intronic areas (blue), locations of the 5HTTLPR polymorphism ~1.4 kb upstream and location of the intronic VNTR near exon 2. B. Translated (red) and non-translated (blue) SNP sites are annotated in the 630 amino acids of the 12-TM-containing SERT protein (54, 157, 158).