Coat color is a key economic trait in wool producing species.Color development and pigmentation are controlled by complex mechanisms in animals.Here,we report the first production of an altered coat color by overexpression of miR-137 in transgenic mice.Transgenic mice overexpressing miR-137 developed a range of coat color changes from dark black to light color.Molecular analyses of the transgenic mice showed decreased expression of the major target gene termed MITF and its downstream genes including TYR,TYRP1 and TYRP2.We also showed that melanogenesis altered by miR-137 is a distinct from that affected by UV radiation in transgenic mice.Our study provides the first mouse model for the study of coat color controlled by miRNAs in animals and may have important applications in wool production.