Fig3A. Copyright: Reprinted with permission from Elsevier from [doi:10.1006/dbio.2000.9788] Dev Biol 224: 29-41, Vivian JL; Olson EN; Klein WH, Thoracic skeletal defects in myogenin- and MRF4-deficient mice correlate with early defects in myotome and intercostal musculature. Copyright 2000