adolescents. At the state level, the effect of genes on daily smoking were lower in states with relatively high taxes on cigarettes and greater controls on vending machine and cigarette advertising, while there was no variation in heritability estimates for smoking onset among adolescents (96). Fletcher (2012) also found that variation in the SNP rs2304297 of nicotinic acetylcholine receptor CHRNA6 moderated the influence of tobacco taxation on multiple measures of tobacco use, such that individuals with the protective G/G polymorphism responded to taxation while others had no response. Only one study investigated GxE between policy and cessation, as a study by Boardman et al. (2011) demonstrated that the genetic influences on smoking desistance (measured using a pair-wise measure indicating the length of time in years for a twin to quit smoking after his/her sibling had quit) increased in importance following restrictive legislation on smoking behaviors during the early and mid-1970s (103).
