The number of genes whose deletion is linked to lifespan extension in mammals is scarce, and none of them are included among those twelve genes common in S. cerevisiae and C. elegans; however, SLC13A5 (homolog of PHO87 in yeast and NAC-2 & NAC-3 in worm) plays a role in age-induced obesity resistance and other metabolic phenotypes in mice28. This evidence concerns the gene SLC13A5 and obesity due to melanocortin 4 receptor deficiency.