Search results for "Drosophila."
showing 10 items of 769 documents
A microsatellite linkage map forDrosophila montanashows large variation in recombination rates, and a courtship song trait maps to an area of low rec…
2009
Current advances in genetic analysis are opening up our knowledge of the genetics of species differences, but challenges remain, particularly for out-bred natural populations. We constructed a microsatellite-based linkage map for two out-bred lines of Drosophila montana derived from divergent populations by taking advantage of the Drosophila virilis genome and available cytological maps of both species. Although the placement of markers was quite consistent with cytological predictions, the map indicated large heterogeneity in recombination rates along chromosomes. We also performed a quantitative trait locus (QTL) analysis on a courtship song character (carrier frequency), which differs be…
Y chromosomes: born to be destroyed
2005
Suppression of recombination is the prerequisite for stable genetically determined sex systems. A consequence of suppression of recombination is the strong bias in the distribution of transposable elements (TEs), mostly retrotransposons. Our results and those from others indicate that the major force driving the degeneration of Y chromosomes are retrotransposons in remodelling former euchromatic chromosome structures into heterochromatic ones. We put forward the following hypotheses. (1) A massive accumulation of retrotransposons occurs early in non-recombining regions. (2) Heterochromatic nucleation centres are formed as a genomic defence mechanism against invasive parasitic elements. The …
The benefits of interpopulation hybridization diminish with increasing divergence of small populations.
2012
Interpopulation hybridization can increase the viability of small populations suffering from inbreeding and genetic drift, but it can also result in outbreeding depression. The outcome of hybridization can depend on various factors, including the level of genetic divergence between the populations, and the number of source populations. Furthermore, the effects of hybridization can change between generations following the hybridization. We studied the effects of population divergence (low vs. high level of divergence) and the number of source populations (two vs. four source populations) on the viability of hybrid populations using experimental Drosophila littoralis populations. Population v…
XRCC5 as a Risk Gene for Alcohol Dependence : Evidence from a Genome-Wide Gene-Set-Based Analysis and Follow-up Studies in Drosophila and Humans
2015
Genetic factors play as large a role as environmental factors in the etiology of alcohol dependence. Although genome-wide association studies (GWAS) enable systematic searches for loci not hitherto implicated in the etiology of alcohol dependence, many true findings may be missed due to correction for multiple testing. The aim of the present study was to circumvent this limitation by searching for biological system-level differences, and then following up these findings in humans and animals. Gene-set based analysis of GWAS data from 1333 cases and 2168 controls identified 19 significantly associated gene-sets of which five could be replicated in an independent sample. Clustered in these ge…
Cholinergic Control of Synchronized Seminal Emissions in Drosophila
2004
0960-9822 (Print) Comparative Study Journal Article Research Support, Non-U.S. Gov't; In many animal species, copulation involves the coordinated release of both sperm and seminal fluid, including substances that change female fertility and postmating behavior. In Drosophila melanogaster, these substances increase female fertility and prevent mating with a second male. By using a PGal4 strain, we targeted together with other cells a dozen cholinergic neurons found only in the male abdominal ganglion (Abg-MAch). Genetic feminization apparently deleted these neurons in males and significantly increased their copulation duration, blocked their fertility in 60% of cases, and only weakly repress…
A set of female pheromones affects reproduction before, during and after mating in Drosophila
2004
0022-0949 (Print) Comparative Study Journal Article Research Support, Non-U.S. Gov't; Sex pheromones are chemical signals used for mate attraction and discrimination in many invertebrate species. These compounds are often complex mixtures with different components having different effects. We tested live Drosophila melanogaster mutant female flies genetically depleted for unsaturated cuticular hydrocarbons, which were then perfumed with these substances to measure their influence on various aspects of reproduction. Female pheromones of the control Cs strain enhanced female attractivity, copulation duration and tended to decrease the number of female progeny of mutant females mated with Cs m…
Genetic feminization of pheromones and its behavioral consequences in Drosophila males
1997
0036-8075 (Print) Journal Article Research Support, Non-U.S. Gov't; Pheromones are intraspecific chemical signals important for mate attraction and discrimination. In the fruit fly Drosophila melanogaster, hydrocarbons on the cuticular surface of the animal are sexually dimorphic in both their occurrence and their effects: Female-specific molecules stimulate male sexual excitation, whereas the predominant male-specific molecule tends to inhibit male excitation. Complete feminization of the pheromone mixture produced by males was induced by targeted expression of the transformer gene in adult oenocytes (subcuticular abdominal cells) or by ubiquitous expression during early imaginal life. The…
Insulin signalling mediates the response to male-induced harm in female Drosophila melanogaster.
2016
Genetic manipulations in nutrient-sensing pathways are known to both extend lifespan and modify responses to environmental stressors (e.g., starvation, oxidative and thermal stresses), suggesting that similar mechanisms regulate lifespan and stress resistance. However, despite being a key factor reducing female lifespan and affecting female fitness, male-induced harm has rarely been considered as a stressor mediated by nutrient sensing pathways. We explored whether a lifespan-extending manipulation also modifies female resistance to male-induced harm. To do so, we used long-lived female Drosophila melanogaster that had their insulin signalling pathway downregulated by genetically ablating t…
A Drosophila male pheromone affects female sexual receptivity.
2006
Sex pheromones are chemical signals frequently required for mate choice, but their reciprocal role on mate preference has rarely been shown in both sexes. InDrosophila melanogasterflies, the predominant cuticular hydrocarbons (CHs) are sexually dimorphic: only females produce 7,11-dienes, whereas 7-tricosene (7-T) is the principal male CH. Males generally prefer females with 7,11-dienes, but the role of 7-T on female behaviour remains unclear. With perfumed males, control females mated faster and more often with males carrying increased levels of 7-T showing that this CH acts as a chemical stimulant forD. melanogasterfemales. Control females—but not antenna-less females—could detect small v…
Genetic feminization of brain structures and changed sexual orientation in male Drosophila
1995
0036-8075 (Print) Journal Article Research Support, Non-U.S. Gov't; The neural basis of sexual orientation in Drosophila was studied by the production of males with regionally feminized brains. Such flies express the female form of the sex determination gene transformer in a limited number of neurons under the control of GAL4 enhancer trap inserts. This method facilitated the creation of lines with a stable pattern of feminization. In tests of sexual preferences, flies that were feminized in a portion of the antennal lobes or in a subset of the corpora pedunculata (mushroom bodies) courted both males and females. These two brain structures, both of which are involved in olfactory processing…