twin sib pairs was not collected during this study, however). Regression models were weighted with sib ship as a covariate to take into account the non-independence in LR among siblings compared to non-related participants (Schuckit et al., 2005a), and the mixed effects of variables in the regression model. Data was tested for normality using the 1-sample Kolmogorov-Smirnov test. While a few study variables were not normally distributed, all residuals were within limits of normality with p >0.05. Non-normal variables were log transformed and re-analyzed with the appropriate inferential test such as linear regression. SPSS version 17.0 (SPSS, 2008) was used in this analysis with significance established at p<0.05. Regression analysis was repeated in a sub-sample comprised of only the African Americans (86% of the sample) to examine the effect of race/ethnicity on LR and RDH. Heritability was determined using polygenic commands for variance component modeling in Sequential Oligogenic Linkage Analysis Routine software (SOLAR, 2009). Pedigree and multiple trait files were loaded into SOLAR. Pedigree files included singleton and twin sib pairs. Separate covariate screening commands were initiated for each LR trait (SRED, SRRD, SRHD and SRTT), with age, gender, body weight, quantity of drinks, and drinks per drinking day as
