Recent studies have demonstrated that the abnormal intestinal microbiota and consequence decrease in fecal contents (especially acetate, propionate, and butyrate) of diet induced obesity (DIO) mice injected with antibiotics is associated with declining methylation of the ADIPOQ and RETN (resistin) promoters, which could be attributed to the down-regulated expression of methylation-related genes, including DNMT1 (encoding DNA methyltransferase 1) and DNMT3a (encoding DNA methyltransferase 3a) 170. Here, RETN is linked to obesity due to melanocortin 4 receptor deficiency.