FlyBase curator comment: this entry is used to capture phenotypic information when the particular allele (or allele combination) used by the author could not be determined but the context of the experiment suggests that the phenotype being described is some kind of loss of function.
The cardiac tube differentiates properly into aorta and heart in mutant embryos. The ostiae cells show a delay in their shape remodelling and are not functional, never completing their differentiation. The heart starts beating normally but almost completely stops after 22 hours of development.
