Table 1 summarizes the study samples. COGA, SAGE, and Yale-Penn were used in the analysis of DSM-IV alcohol dependence diagnosis and DSM-IV alcohol dependence criterion count. In total, there were 2,872 alcohol dependence cases and 1,672 controls. A total of 5,942 individuals had data on DSM-IV criterion count. COGA and NIAAA datasets were used for SRE analysis; SRE-5 and SRE-T analyses included data on 1,546 individuals in total. In terms of variants, 632,882, 601,545, 637,753, and 580,705 SNPs were included in the COGA, SAGE, Yale-Penn, and NIAAA data respectively (Table 1). RFMix estimated 14,376, 14,958, 15,336, and 14,118 African ancestry blocks for COGA, SAGE, Yale-Penn, and NIAAA respectively (Table 1). Using the R package CODA (Plummer et al., 2005), 273.82 effective African ancestry blocks were estimated across these four cohorts.
