Finally, we conducted analyses to evaluate the impact of any measurement non-invariance on rs16969968, the functional coding single nucleotide polymorphism (SNP) in the nicotinic acetylcholine receptor gene CHRNA5, that is robustly associated with nicotine dependence (Hancock et al., In-press). Rs16969968 was either genotyped or imputed with high quality (IMPUTE2 “info” quality metric = 0.99–1) in each of the five study samples and additively coded (ranging from 0 to 2 for the number of G alleles carried) for analysis, as previously described (Hancock et al., 2017a).
