Transcription factor required for the development of hypaxial muscles. First expressed at the dorsal intermediate region of the neural tube at the 5-somite stage, expression is extended along the rostral caudal axis by the late stages of segmentation (PubMed:19216761). Expressed at the presumptive fin bud at 24 hours post-fertilization (hpf) and then at the fin bud at 48 hpf (PubMed:19216761). Morpholino knockdown results in decreased myod1 expression in the fin bud of embryos.