Project description:Transcriptional profiling of Drosophila melanogaster 2nd chromosome substitution lines; Background chromosomes are identical across lines; 2nd chromosomes are different across line and can be homozygous or heterozygous within each line Keywords: Natural variation
Project description:Thomas Hunt Morgan and colleagues identified variation in gene copy number in Drosophila in the 1920s and 1930s and linked such variation to phenotypic differences [Bridges, C. B. (1936) Science 83, 210]. Yet the extent of variation in the number of chromosomes, chromosomal regions, or gene copies, and the importance of this variation within species, remain poorly understood. Here, we focus on copy-number variation in Drosophila melanogaster. We characterize copy-number polymorphism (CNP) across genomic regions, and we contrast patterns to infer the evolutionary processes acting on this variation. Copy-number variation in D. melanogaster is non-randomly distributed, presumably due to a mutational bias produced by tandem repeats or other mechanisms. Comparisons of coding and noncoding CNPs, however, reveal a strong effect of purifying selection in the removal of structural variation from functionally constrained regions. Most patterns of CNP in D. melanogaster suggest that negative selection and mutational biases are the primary agents responsible for shaping structural variation. Keywords: comparative genomic hybridization
Project description:Background: Differences in levels of gene expression among individuals are an important source of phenotypic variation within populations. Recent microarray studies have revealed that expression variation is abundant in many species, including Drosophila melanogaster. However, previous expression surveys in this species generally focused on a small number of laboratory strains established from derived populations. Thus, these studies were not ideal for population genetic analyses. Results: We surveyed gene expression variation in adult males of 16 D. melanogaster strains from two natural populations, including an ancestral African population and a derived European population. Levels of expression polymorphism were nearly equal in the two populations, but a higher number of differences was detected when comparing strains between populations. Expression variation was greatest for genes associated with few molecular functions or biological processes, as well as those expressed predominantly in males. Our analysis also identified genes that differed in expression level between the European and African populations, which may be candidates for adaptive regulatory evolution. Genes involved in flight musculature and fatty acid metabolism were over-represented in the list of candidates. Conclusions: Overall, stabilizing selection appears to be the major force governing gene expression variation within populations. However, positive selection may be responsible for much of the between-population expression divergence. The nature of the genes identified to differ in expression between populations may reveal which traits were important for local adaptation to the European and African environments. Keywords: Natural variation
Project description:The mechanisms underlying natural variation in lifespan and ageing rate remain largely unknown. We performed microarray experiment to characterise genome-wide expression patterns of a long-lived, natural variant of Drosophila melanogaster resulting from selection for starvation resistance (SR) and compare it with normal-lived control flies (C).
2012-04-01 | GSE36582 | GEO
Project description:Natural selection on sleep duration in Drosophila melanogaster
Project description:Our objective was to determine whether gene expression in Drosophila melanogaster selectively bred for long or short night sleep duration changes detectably across generations. To meet this objective, we performed transcriptional profiling of ten pooled whole adult individuals from four selected populations and two control populations across 13 generations. We quantified differential expression among selection scheme (long sleep, short sleep, or unselected control), generation (generation 0; then generations 2-13), and sex for each gene.
Project description:Absolute (molar) quantification determines proteins stoichiometry in complexes, networks and metabolic pathways. We employed MS Western workflow to determine molar abundances of proteins critical for morphogenesis and phototransduction (PT) in eyes of Drosophila melanogaster using a single chimeric 264 kDa protein standard that covers, in total, 197 peptides from 43 proteins. Each protein was independently quantified with 2 to 4 proteotypic peptides with the coefficient of variation of less than 15 %, better than 1000-fold dynamic range and sub-femtomole sensitivity. We determined molar abundances and stoichiometric ratios of the components of the PT machinery and the rhabdomere, and how they are changing when rhabdomere morphogenesis is perturbed by genetic manipulation of the evolutionary conserved gene crumbs (crb).
Project description:Background: Differences in levels of gene expression among individuals are an important source of phenotypic variation within populations. Recent microarray studies have revealed that expression variation is abundant in many species, including Drosophila melanogaster. However, previous expression surveys in this species generally focused on a small number of laboratory strains established from derived populations. Thus, these studies were not ideal for population genetic analyses. Results: We surveyed gene expression variation in adult males of 16 D. melanogaster strains from two natural populations, including an ancestral African population and a derived European population. Levels of expression polymorphism were nearly equal in the two populations, but a higher number of differences was detected when comparing strains between populations. Expression variation was greatest for genes associated with few molecular functions or biological processes, as well as those expressed predominantly in males. Our analysis also identified genes that differed in expression level between the European and African populations, which may be candidates for adaptive regulatory evolution. Genes involved in flight musculature and fatty acid metabolism were over-represented in the list of candidates. Conclusions: Overall, stabilizing selection appears to be the major force governing gene expression variation within populations. However, positive selection may be responsible for much of the between-population expression divergence. The nature of the genes identified to differ in expression between populations may reveal which traits were important for local adaptation to the European and African environments. We used dual channel microarrays to compare genome-wide expression profiles in adult males from 16 inbred strains derived from two natural populations. In total 80 hybidizations were performed including dye-swaps. The hybridization scheme consisted of a balanced loop design, which allowed an unbiased comparison of relative expression levels within and between populations.