We attempted replication of a recently reported association of specific SNPs in the gene SGIP1 with resting theta EEG power and alcohol use disorders (Hodgkinson et al., 2010). We did not find evidence of association of any of these eight SNPs with either alcohol dependence (diagnosis or symptom count) or theta EEG power in the current sample. Our alcohol phenotype was not identical to that analyzed in the original study (i.e., alcohol dependence here, compared to either alcohol abuse or dependence in the original study). However, the theta EEG phenotype analyzed here was the same as that used by Hodgkinson et al. (2010). This failure to replicate should be considered in the context of ancestral differences, and thus allele frequency or linkage disequilibrium (LD) differences, between the current and original samples. The present analyses included individuals of European and/or African ancestry, while the initial findings were reported for a sample of Plains Indians. Although patterns of LD within the SGIP1 gene differ markedly between individuals of European and African ancestry (see Figure, Supplemental Digital Content 1, showing that LD is
