As the B6 strain mouse is the most commonly used model for HFD-induced obesity, the HO-1+/− mice, originally on the B6/129SV mixed genetic background, were backcrossed six generations onto the C57BL/6J genetic background prior to be used as donors for the BMT to C57BL/6J recipient mice. This evidence concerns the gene HMOX1 and obesity due to melanocortin 4 receptor deficiency.