RESUMEN
The regulation of NaCl is essential for the maintenance of cellular tonicity and functionality, and excessive salt exposure has many adverse effects. The fruit fly, Drosophila melanogaster, is a good osmoregulator and some strains can survive on media with very low or high NaCl content. Previous analyses of mutant alleles have implicated various stress signaling cascades in NaCl sensitivity or tolerance; however, the genes influencing natural variability of NaCl tolerance remain for the most part unknown. Here, we use two approaches to investigate natural variation in D. melanogaster NaCl tolerance. We describe four D. melanogaster lines that were selected for different degrees of NaCl tolerance, and present data on their survival, development, and pupation position when raised on varying NaCl concentrations. After finding evidence for natural variation in salt tolerance, we present the results of Quantitative Trait Loci (QTL) mapping of natural variation in larval and pupal NaCl tolerance, and identify different genomic regions associated with NaCl tolerance during larval and pupal development.
Asunto(s)
Drosophila melanogaster/crecimiento & desarrollo , Tolerancia a la Sal/fisiología , Animales , Medios de Cultivo , Drosophila melanogaster/genética , Larva/genética , Larva/crecimiento & desarrollo , Pupa/genética , Pupa/crecimiento & desarrollo , Sitios de Carácter Cuantitativo/genética , Tolerancia a la Sal/genéticaRESUMEN
Drosophila melanogaster, like other organisms, move and orient themselves in response to the earth's gravitational force. The ability to sense and respond to gravity is essential for an organism to navigate and thrive in its environment. The genes underlying this behaviour in Drosophila remain elusive. Using 88 recombinant inbred lines, we have identified four quantitative trait loci (QTLs) that contribute to adult gravitaxis (geotaxis) behaviour in Drosophila. Candidate genes of interest were selected from the QTLs of highest significance based on their function in chordotonal organ formation. Quantitative complementation tests with these candidate genes revealed a role for skittles in adult gravitaxis behaviour in D. melanogaster.
Asunto(s)
Mapeo Cromosómico , Drosophila melanogaster/genética , Sensación de Gravedad/genética , Sitios de Carácter Cuantitativo/genética , Animales , Proteínas de Drosophila/genética , Drosophila melanogaster/fisiología , Femenino , Masculino , Recombinación Genética , Órganos de los Sentidos/fisiologíaRESUMEN
This study links natural variation in a Drosophila melanogaster overwintering strategy, diapause, to the insulin-regulated phosphatidylinositol 3-kinase (PI3-kinase) gene, Dp110. Variation in diapause, a reproductive arrest, was associated with Dp110 by using Dp110 deletions and genomic rescue fragments in transgenic flies. Deletions of Dp110 increased the proportion of individuals in diapause, whereas expression of Dp110 in the nervous system, but not including the visual system, decreased it. The roles of phosphatidylinositol 3-kinase for both diapause in D. melanogaster and dauer formation in Caenorhabditis elegans suggest a conserved role for this kinase in both reproductive and developmental arrests in response to environmental stresses.
