The external orofacial morphology, perioral bristle distribution and feeding behaviour of Dugong dugon, Trichechus inunguis, T. senegalensis and T. manatus are described. Despite their differing orofacial morphology, dugongs and trichechids possess six similar regions: the oral disk, orofacial ridge, supradisk, chin and upper and lower bristle (modified vibrissae) pads. All living sirenians pos...

The morphogenesis of Drosophila sensory bristles is dependent on the function of their actin and microtubule cytoskeleton. Actin filaments are important for bristle shape and elongation, while microtubules are thought to mediate protein and membrane trafficking to promote growth. We have identified an essential role for the bristle cuticle in the maintenance of bristle structure and shape at la...

In the present study an attempt has been made to characterize the genetic ;;factors'' controlling quantitative characters, bristle numbers, in Drosophila melanogaster. A low sternopleural bristle multiple recessive marker third chromosome was used to analyze a high sternopleural third chromosome, in a high sternopleural bristle background. An attempt was made to estimate the minimum number of ;...

The chromosomal architecture of genotype x environment interactions was investigated in lines of Drosophila melanogaster selected for increased or decreased sternopleural bristle number at 18 degrees , 25 degrees and 29 degrees . In general, interactions were found to have a stabilizing effect upon the bristle phenotype, in the sense that the genotype x environment interaction tended to increas...

Quantitative trait loci (QTLs) responsible for variation in sternopleural bristle number in crosses between the laboratory lines of Drosophila melanogaster OregonR and CantonS were mapped using information from allele frequency changes of two families of retrotransposon markers in divergently selected populations. QTL effects and positions were inferred by likelihood, using transition matrix it...

The tuh-1 maternal effect locus contains two naturally occurring isoalleles, tuh-1h and tuh-1g. Until recently there has been no possibility to distinguish between the tuh-lh and the tuh-1g maternal effects other than evaluating their effect on the Bithorax-Complex (BXC) Abdominal B (Abd-B) mutant tuh-3. However, in this report we identify a bristle phenotype associated with the tuh-1 locus tha...

Signaling molecules have pleiotropic functions and are activated by various extracellular stimuli. Protein kinase C (PKC) is activated by diverse receptors, and its dysregulation is associated with diseases including cancer. However, how the undesired activation of PKC is prevented during development remains poorly understood. We have previously shown that a protein kinase, IKKε, is active at t...

Hox genes play a major role in the morphological diversification of the anteroposterior body axis of animal embryos by switching the fates of segments between alternative developmental pathways [1]. In their role of controlling segment diversity, Hox proteins are responsible for many different morphological structures and cell types within a given segment. But it is still largely a mystery how ...

Drosophila bristles display a precise orientation and curvature. An asymmetric extension of the socket cell overlies the newly emerging bristle rudiment to provide direction for bristle elongation, a process thought to be orchestrated by the nerve dendrite lying between these cells. Scanning electron microscopic analysis of individual bristles showed that curvature is planar and far greater nea...

Drosophila bristles display a precise orientation and curvature. An asymmetric extension of the socket cell overlies the newly emerging bristle rudiment to provide direction for bristle elongation, a process thought to be orchestrated by the nerve dendrite lying between these cells. Scanning electron microscopic analysis of individual bristles showed that curvature is planar and far greater nea...