Fusion of developing muscles is abnormal in homozygous embryos.
Dorsal vessel and visceral mesoderm is unaffected in embryos homozygous for the "rost30A" chromosome (carrying both rost30A and sns43-49 but major distortions occur in somatic mesoderm. Late stages of embryonic development show many unfused myoblasts. First distortions are visible during germ-band retraction. Unfused myoblasts are often arranged in specific locations where in the wild type ventral, pleural and longitudinal muscles form.