For DSM-IV alcohol dependence diagnosis and DSM-IV alcohol dependence criterion count, we did not find any genome-wide significant blocks. Most samples in this study were included in a GWAS meta-analysis of alcohol dependence in AA and the significant association of rs2066702 in ADH1B was identified (Walters et al., 2018). The protective role of rs2066702 was confirmed in a GWAS of alcohol dependence from the Million Veteran project (Kranzler et al., 2019). However, other variants in this gene, e.g., rs1229984, also have protective effects in other ancestries, including EA. In the current admixture mapping, the inferred African ancestry block around this gene was large and included all known variants with protective effects; therefore, admixture mapping doesn’t have sufficiently high resolution to detect association. We also examined the other AA-only finding from the Million Veteran Project (rs72900220) (Kranzler et al., 2019) and found no evidence of association using the current admixture mapping approach. One possible explanation could be the low MAF of this variant (3.9%); therefore, even with admixture mapping, a much larger sample size may be required to detect the association with this variant.
