Genetic markers in the porcine melanocortin-4 receptor (MC4R) gene are disclosed which are associated with fat content, growth rate, and feed consumption. Further, novel sequence data from regions of the gene are disclosed which may be used in a PCR test to screen for the presence of the marker. The genetic marker may be used to screen animals for breeding purposes which have the desired traits regarding fat content, growth rate, and feed consumption. Kits which take advantage of the PCR test are also disclosed.