develops from expresses pon external sensory organ precursor cell external sensory organ precursor cell pNa antennal olfactory receptor neuron precursor Nab 2019-12-12T12:00:51Z Terminal daughter cell of an external sensory organ precursor cell pNa in the developing antenna. It may undergo apoptosis or differentiate into an olfactory receptor neuron, depending upon which sensillum it is in. It can be distinguished from the Naa precursor based on its expression of partner of numb (pon). fly_anatomy.ontology FBbt:00048524