Differentiation capacities of the dorsal metathoracic (haltere) disc ofDrosophila melanogaster

Abstract

The mature haltere disc, when implanted into a larva of the same age, undergoes metamorphosis along with the host, and produces a haltere, haltere sclerite, notum III, and pleural process. Implants ordinarily form an inverted vesicle, into which the haltere is frequently everted, usually only partly. Many "adventitious bristles" may be formed which are not foundin situ. It was found thatsc may reduce, andmwh may increase the number of sensilla.On the basis of results obtained from transplanted disc fragments an organ map of the haltere disc was constructed, which shows the presumptive haltere area to be located in the posterio-central part of the disc, while the anterio-medial part forms the thoracic structures dorsal to the haltere, and the posterio-lateral part the thoracic structures ventral to it. The anlage of the "adventitious bristles" is probably within the notum area. The haltere anlage proper is concentric; the prospective distal capitellum is located in the center, and is surrounded by the anlagen of the more proximal segments.The organ map of the haltere disc is compared with that of other discs. Organ maps seem to be basically concentric. There is a close homology between the maps of the wing and the haltere disc.

Expression of the pair-rule geneodd Oz (odz) in imaginal tissues

“…3e) appears in sites homologous to the strongest expression sites in the prospective thoracic and wing-hinge anlagen in wing discs. These proximal positions correspond to presumptive notum, scabellum, and pedicel, and are strongest in regions that will give rise to the scabellar and pedicalar sensilla (Ouweneel and van der Meer, 1973). odz enhancer trap staining appears at the same sites as the protein, but primarily in the punctate Fig.…”

Maintenance of Positional Identity of Neural Progenitors in the Embryonic and Postnatal Telencephalon

“…Mutations in Hox genes do not result in the loss of segment number but rather cause a change in segment identity. For example, the Hox gene Ubx is expressed in the third thoracic segment where it is required to generate an appendage called a haltere (Ouweneel and van der Meer, 1973 ; Lawrence and Morata, 1983 ). In the absence of Ubx , the third thoracic segment fails to generate halters and instead makes an additional wing, an appendage that normally develops from an adjacent segment.…”

Haltere determination and mutations at the bithorax locus

“…ventral proximal radius of the wing (which corresponds to the pedicellar and scabellar segments of the haltere [25,26]) as well as the proximal costa appeared mixed [4, 181. That is, the morphology was partially wing-like and partially haltere-like. The transformation of the haltere in bx3,/UbxlO1 flies was in a number of ways somewhat more extreme than bx3 flies.…”