Figure 2B. Copyright: Reprinted with permission from Elsevier from [doi:10.1016/S0925-4773(98)00122-1] Mech Dev 76: 197-201, Robb L; Hartley L; Wang CC; Harvey RP; Begley CG, musculin: a murine basic helix-loop-helix transcription factor gene expressed in embryonic skeletal muscle. Copyright 1998.