Project description:We generated 4 separate subpopulations of selected flies from 1 starting population of a mixture of Canton-S flies. Two of the populations (AggrI and AggrII) were selected for increased aggression by picking males from a population cage that engaged in the most intense fighting (known as escalation behavior). Thirty males were selected every generation (from a total of 120 males per cage) per line and mated with random virgin females from that same generation. Two control populations (NeutrI and NeutrII) were selected by picking random males from the population cage after 15-30 aggressive males were removed. After 21 generations of selection males from the Aggr lines were dramatically more aggressive than males from the Neutr lines. The Neutr lines did not significantly differ from the starting population although a trend of decreased aggression was visible. Experiment Overall Design: Four populations were analyzed. Two were selected for increased aggression and two were reference groups, selected for a decrease but with no significant effect.
Project description:A method for the long-term maintenance of germ-free flies was established using aseptic isolators. The methodology effectively and reliably yields large numbers of germ-free flies in homogeneous cultures. Germ-free flies exhibited increased lifespan (only female flies) and decreased egg production, markedly reduced fat storage, less midday sleep, and enhanced aggressiveness (male flies). Fructilactobacillus—a species of fly intestinal microbes—was re-colonized in germ-free flies, and these gnotobiotic flies were successfully maintained for numerous generations. The proteome of those flies were analyzed.
Project description:Genes relevant to manifestion of and variation in aggression behavior might be differentially expressed in lines selected for divergent levels of aggression. Experiment Overall Design: Drosophila males were assessed for their aggression levels in a behavioral assay that quantified aggressive encounters. A subset of the sampled population was selected as parents for the next generation, with High, Low, and Control selection groups maintained. This artificial selection was continued for 28 generations, with a variety of other behavioral and life history traits assessed for correlation with response to selection for aggression. At generation 28, male and female flies were collected for RNA extraction and subsequent gene expression analysis.
Project description:Although radiation effects have been extensively studied, the biological effects of low-dose radiation (LDR) are controversial. This study investigates LDR-induced alterations in locomotive behavior and gene expression profiles of Drosophila melanogaster. We measured locomotive behavior using larval pupation height and rapid iterative negative geotaxis (RING) assay after exposure to 0.1 Gy gamma-radiation (dose rate of 16.7 mGy/h). We also observed chronic LDR effects on development (pupation and eclosion rates) and longevity (life span). To identify chronic LDR effects on gene expression, we performed whole-genome expression analysis using gene-expression microarrays, and confirmed the results using quantitative real-time PCR. Pupation height was significantly higher after LDR treatment at the first larval instar. Locomotive behavior of male flies was significantly greater approximately 3M-BM--5 weeks after LDR, but pupation and eclosion rates and life spans were not significantly different. Genome-wide expression analysis identified 344 genes that were differentially expressed in irradiated larvae compared with those of controls. We identified several genes belonging to larval behavior functional groups such as locomotive behavior and oxidation reduction, and genes involved in conventional functional groups modulated by irradiation such as defense response, sensory and perception. Four candidate genes were confirmed as differentially expressed genes in irradiated larvae using qRT-PCR. These data suggest that LDR stimulates locomotion-related genes, and these genes can be used as potential markers for LDR. Eggs were collected from 5-day-old female flies and cultivated for 24 h on standard medium. Then, twenty larvae were manually selected and seeded on fresh standard medium in a new vial. After transfer, the experimental group of first-instar larvae was immediately irradiated with chronic gamma-radiation at a dose rate of 16.7 mGy/h. After treatment, gamma-irradiated flies and non-irradiated control flies were maintained in the same incubator at 25degC.
Project description:We generated 4 separate subpopulations of selected flies from 1 starting population of a mixture of Canton-S flies. Two of the populations (AggrI and AggrII) were selected for increased aggression by picking males from a population cage that engaged in the most intense fighting (known as escalation behavior). Thirty males were selected every generation (from a total of 120 males per cage) per line and mated with random virgin females from that same generation. Two control populations (NeutrI and NeutrII) were selected by picking random males from the population cage after 15-30 aggressive males were removed. After 21 generations of selection males from the Aggr lines were dramatically more aggressive than males from the Neutr lines. The Neutr lines did not significantly differ from the starting population although a trend of decreased aggression was visible. Keywords: selection for male aggression