1996; Stoltenberg, 2003). It is important to note that Hu et al. (2006) have suggested that a triallelic coding of 5-HTTLPR, which involves a nearby single nucleotide polymorphism (SNP; rs25531), may be more accurate. In Caucasians, approximately 10% of L alleles contain the SNP (Haberstick et al., 2015), but brain imaging and molecular studies are not entirely consistent as to the functional significance of this SNP (Martin, Cleak, Willis-Owen, Flint, & Shifman, 2007; Murthy et al., 2010; Philibert, Sandhu, Hollenbeck, Gunter, Adams, Madan, 2007).
