0000000001195835
AUTHOR
Marcos González-gaitán
Number, identity, and sequence of the Drosophila head segments as revealed by neural elements and their deletion patterns in mutants.
The development of the insect head tagma involves massive rearrangements and secondary fusions of segment anlagen during embryogenesis. Due to the lack of reliable morphological markers, the number, identity, and sequence of the head segments, particularly in the pregnathal region, are still a matter of ongoing debates. We examined the complex array of internal structures of the embryonic Drosophila melanogaster head such as the sensory structures and nerves of the peripheral and stomatogastric nervous systems, and we used embryonic head mutations causing a lack of overlapping segment anlagen to unravel the segmental identity and the sequence of the neural elements. Our results provide evid…
Analysis of neural elements in head-mutant Drosophila embryos suggests segmental origin of the optic lobes.
We describe the development of 20 sensory organs in the embryonic Drosophila head, which give rise to 7 sensory nerves of the peripheral nervous system (PNS), and 4 ganglia of the stomatogastric nervous system (SNS). Using these neural elements and the optic lobes as well as expression domains of the segment polarity gene engrailed in the wild-type head of Drosophila embryos as markers we examined the phenotype of different mutants which lack various and distinct portions of the embryonic head. In the mutants, distinct neural elements and engrailed expression domains, serving as segmental markers, are deleted. These mutants also affect the optic lobes to various degrees. Our results suggest…