Univ. of Illinois researchers used a total of 192 early weaned Simmental steers to evaluate the relationship of the GeneSTAR marker for marbling to intramuscular fat (IMF) deposition and the expected progeny difference (EPD) for marbling. Steers were weaned at 88 days of age, fed a high-concentrate diet and slaughtered at 423 days of age. DNA samples were taken for GeneSTAR marbling analysis. Steers with allele types of 0-STAR (n=47), 1-STAR (n=95), and 2-STAR (n=33) had no significant effect on marbling score, chemically determined IMF percentage, or percent grading Low Choice and higher. Furthermore, there were no significant differences in performance or other carcass traits among the three genotypes. Conversely, marbling EPD was highly correlated with marbling score and IMF percentage. The authors concluded that the GeneSTAR marker for marbling was not an efficacious predictor of IMF deposition under the conditions of this study (Rincker et al. 2006. J. Anim. Sci. 84:686).