Demonstration of sensory neurones in the ectopic cuticle of spineless-aristapedia, a homoeotic mutant of Drosophila

Abstract

MANY mutations in Drosophila melanogaster cause the development of body parts in inappropriate places. Several of these homoeotic mutations (reviewed in ref. 1) result in the appearance of leg bristles and other leg cuticular structures in place of their antennal counterparts. In the mutant spineless-aristapedia (ss^a, 3–58.5) the antennal arista is replaced by tarsal segments²; the mutations Antennapedia (Antp, 3–48) and Nasobemia (Ns, 3–48) produce a more extreme transformation: most of the antennal cuticular structures are transformed into leg cuticle, and, in the latter, part of the head cuticle is replaced by sternopleural cuticle^3,4. In insects the sensory neurones are derived from epidermal cells⁵. When sensory epidermis is surgically transplanted to ectopic sites, neurones develop from it and form connections with the central nervous system⁶. These neurones act according to the type of epidermis from which they are derived rather than according to the position in which they develop⁶. In homoeotic mutants cuticular structures develop at ectopic sites as a result of genetic modification. In this report I examine whether in homoeotic mutants sensory neurones are formed, and, if so, whether they behave according to the homoeotic structures that develop, or according to their general position in the body.