No description available.

Gustatory sensilla in the blowfly Phormia regina contain five phenotypically distinct neurons. The neurons are thought to arise from a common precursor, however, little is known about their lineage or about how each one comes to assume a unique fate. This study examines the possibility that the neurons arise from a repeatedly dividing stem cell, in which case, the neuronal fate may be determined by birth order. To determine if the neurons are born at different times, their times of birth were assessed. This was achieved by using Hydroxyurea to arrest the gustatory neural precursors at different times throughout the development of the sensillum. Thus, each neuron's time of birth, relative to the arrest, was reflected by its presence or absence. The results show that the five neurons are born in a relatively short interval, and hence, cannot arise from five successive divisions of a stem cell. Therefore, the fate of each neuron cannot be determined solely by its time of birth.