Cellular heterogeneity during vertebrate skeletal muscle development

Although skeletal muscles appear superficially alike at different anatomical locations, in reality there is considerably more diversity than previously anticipated. Heterogeneity is not only restricted to completely developed fibers, but is clearly apparent during development at the molecular, cellular and anatomical level. Multiple waves of muscle precursors with different features appear before birth and contribute to muscular diversification. Recent cell lineage and gene expression studies have expanded our knowledge on how skeletal muscle is formed and how its heterogeneity is generated. This review will present a comprehensive view of relevant findings in this field. (c) 2007 Elsevier Inc. All rights reserved.