We have mapped quantitative trait loci (QTL) for Drosophila mechanosensory bristle number in six recombinant isogenic line (RIL) mapping populations, each of which was derived from an isogenic chromosome extracted from a line selected for high or low, sternopleural or abdominal bristle number and an isogenic wild-type chromosome. All RILs were evaluated as male and female F(1) progeny of crosse...

The highly elongated bristles of Drosophila have proven to be a valuable model system for studying cellular morphogenesis. Extending bristles contain a series of large bundles of actin filaments juxtaposed to the plasma membrane and centrally located microtubules. Models to explain the extension of the bristle have principally focused on the assembly of actin filaments at the distal tip of the ...

I n a former paper (PAYNE 1918) I gave the results of an experiment to increase bristle number on the scutellum of Drosophila melanogaster. While plus and minus variations in bristle number may occur in cultures of wild stock, it may be said that four bristles’is the normal number in wild flies. In the strain selected f a r extra bristles, a female with five and a male with four bristles were t...

Macrochaetes (large bristles), functioning as mechanoreceptors, are located in an orderly fashion on the drosophila head and body forming a species-specific bristle pattern. A simple organization of each bristle organ, comprising only four specialized cells, and conservation of bristle pattern make macrochaetes a convenient model for studying the development patterns of spatial structures with ...

Previously, we mapped quantitative trait loci (QTL) affecting response to short-term selection for abdominal bristle number to seven suggestive regions that contain loci involved in bristle development and/or that have adult bristle number mutant phenotypes, and are thus candidates for bristle number QTL in natural populations. To test the hypothesis that the factors contributing to selection r...

I N D. melanogaster, the genetic control of differentiation at specific sites is conveniently studied by the use of genetic mosaics. In wild-type flies, a definite number of macrochaetae or bristles is formed at specific sites of the thorax. Certain mutant genes are quite specific in their effects on bristle formation. The effect of achaete (ac) , for example, is primarily restricted to removal...

A restriction enzyme survey of a 57-kb region including the gene Delta uncovered 53 polymorphic molecular markers in a sample of 55 naturally occurring chromosomes. A permutation test, which assesses the significance of the molecular marker with the largest effect on bristle variation in four genetic backgrounds relative to permuted data-sets, found two sites that were independently associated ...

Adolescence is a period of heightened vulnerability for the onset of internalizing psychopathology. Characterizing developmental patterns of symptom stability, progression, and co-occurrence is important in order to identify adolescents most at risk for persistent problems. We use latent growth curve modeling to characterize developmental trajectories of depressive symptoms and four classes of ...

A section of the third chromosome of D. melanogaster some 25 to 40 centimorgans long including sr was transferred from a wild-type stock selected by Latter for high scutellar bristle number into a scute stock with a large number of scutellar bristles. This segment is shown to have a large effect on the bristle numbers of wild-type flies, to reduce the strength of canalization of the scute pheno...