University of Oregon scientists say they have identified a gene that is the key switch that allows embryonic cells to form into muscles in zebrafish. Much like students in a kindergarten class lining up to go to lunch, the trigger gene, which is identified as Smarcd3, must align correctly with two other genes for muscle formation to begin, a process known as myogenesis, said principal investigator Monte Westerfield, a professor of biology and researcher in the UO Institute of Neuroscience.