Duplicated neural structure in bithorax mutant Drosophila.

The bithorax complex (BX-C) of genes in Drosophila control the segmental identity of the thoracic and abdominal cuticle. In flies containing BX-C mutations causing meta- to mesothoracic transformation, the mesothoracic branching pattern of a well-studied identified neuron is faithfully duplicated in the metathoracic ganglion. Thus these mutations also cause the duplication of mesothoracic cues involved in this neuron's branching.