The importance of our SNP-based gene identification approach is indicated by, for example, that proteins encoded by the PNLIP and PNLIPRP2 genes, which were not associated to fatness phenotypes in pigs before, are the target of Orlistat (tetrahydrolipstatin), a drug used for treating obesity in humans (data not shown). The gene discussed is PNLIP; the disease is obesity due to melanocortin 4 receptor deficiency.