Skeletal muscle stem cells, called satellite cells, are quiescent and considered a heterogeneous population.Recent studies demonstrate that Pax7, a well-defined transcriptional regulator of satellite cell functions,influences the heterogeneity of satellite cell subpopulations (Pax7Hi and Pax7Low).However, the mechanism by which these subpopulations are established and maintained during myogenesis is unknown.Recently, we found that miRNAs, especially myostatin-regulated and predominantly expressed in skeletal muscle, mediates satellite cell heterogeneity during muscle development and regeneration.By generating the transgenic mice and knockout mice of those miRANs, we have established unique genetic models in which the Pax7hi and Pax7Lowsatellite cell nubpopulations were enriched during development.With those mice models, we have investigated functional role of those subpopulations and the molecular mechanism for establishing and maintaining those subpopulations.together, those mice models provide unique genetic system for investigating the cellular features and biological functions of Pax7Low and Pax7hi satellite cells during muscle development and regeneration.