Somitogenesis

Somitogenesis is the process by which somites are produced. Somites are bilaterally paired blocks of mesoderm that form along the anterior-posterior axis of the developing embryos of segmented animals, often originating in an anterior to posterior direction. In vertebrates, somites give rise to skeletal muscles, trunk skeleton and dermis, and form from presomitic mesoderm (PSM). Different organisms have different numbers of somites, for example frogs have ~10, humans have 33, fish have ~48, and snakes have more than 300. Somitogenesis is an active area of investigation in many laboratories.