Project description:Understanding the genotype-phenotype map and how variation at different levels of biological organization is associated are central topics in modern biology. Fast developments in sequencing technologies and other molecular omic tools enable researchers to obtain detailed information on variation at DNA level and on intermediate endophenotypes, such as RNA, proteins and metabolites. This can facilitate our understanding of the link between genotypes and molecular and functional organismal phenotypes. Here, we use the Drosophila melanogaster Genetic Reference Panel and nuclear magnetic resonance (NMR) metabolomics to investigate the ability of the metabolome to predict organismal phenotypes. We performed NMR metabolomics on four replicate pools of male flies from each of 170 different isogenic lines. Our results show that metabolite profiles are variable among the investigated lines and that this variation is highly heritable. Second, we identify genes associated with metabolome variation. Third, using the metabolome gave better prediction accuracies than genomic information for four of five quantitative traits analyzed. Our comprehensive characterization of population-scale diversity of metabolomes and its genetic basis illustrates that metabolites have large potential as predictors of organismal phenotypes. This finding is of great importance, e.g., in human medicine, evolutionary biology and animal and plant breeding.
Project description:Differences in the selective pressures experienced by males and females are believed to be ubiquitous in dioecious organisms and are expected to result in the evolution of sexually antagonistic alleles, thereby driving the evolution of sexual dimorphism. Negative genetic correlation for fitness between the sexes has been documented, however, the identity, number and location of loci causing this relationship are unknown. Here we show that a large proportion of Drosophila melanogaster transcripts are associated with the interaction between genomic haplotype and gender and that at least 8% of loci in the fly genome are currently evolving under sexually antagonistic selection. We measured gene expression of adult males and females of Drosophila melanogaster from 15 hemiclone lines, showing either high-male/low-female fitness, high-female/lowmale fitness or average fitness in both sexes. Data from four replicates for each sex/line are presented, giving a total of 120 arrays.
Project description:We generated RNA-seq data of Drosophila simulans and Drosophila mauritiana developing male genitalia in order to identify expression level differences between these species. These species are closely related, yet have dramatic differences in their male genital morphologies. Three independent RNA-seq library replicates were generated for Dsim w501 and Dmau D1 developing male genitalia. Flies were reared under the above conditions, and white pre-pupae collected. Males were selected using gonad size and allowed to develop in a humid container at 25ºC until stages 2 and 4.5 (see staging guide in (Hagen et al., 2019); tartan underlies the evolution of Drosophila male genital morphology). Between these stages, the claspers develop from a ridge structure to a distinct appendage separate from the surrounding tissue, and the posterior lobe has begun to extend outwards from the lateral plate primordia (Hagen et al., 2019). The heads of pupae were impaled with a needle onto a charcoal agar plate and submerged in 1xPBS. Dissection scissors were used to remove the distal tip of the pupal case and the outer membrane, and pressure applied to the abdomen to allow the developing genitalia to be quickly expelled from the pupal case and dissected away from the abdomen. Note that the entire genital arch, including internal genital organs (but not including abdominal tissue), was isolated for RNA extraction. The genitalia from fifteen males from each stage were collected and placed directly into TRIzol. RNA was then extracted using standard procedures. Quality and quantity of RNA was verified using a Qubit, and samples were sent to the Centre for Genomic Research at the University of Liverpool where dual-indexed, strand-specific RNA-seq libraries were prepared using NEBNext polyA selection and Ultra Directional RNA preparation kits. Samples were then sequenced using Illumina HiSeq 4000 (paired-end, 2x150 bp sequencing). Dsim w501 and Dmau D1 reads were mapped against reannotated reference coding sequences (Torres-Oliva et al., 2016).
Project description:The Drosophila genitalia develop from an imaginal disc that is patterned during the larval period and undergoes morphogenesis during the pupal period. Although the genetic hierarchy that controls sexual identity in Drosophila is well characterized, the downstream genes that effect sexually dimorphic development of the genitalia are largely unknown. We used microarrays to profile gene expression in female and male genital imaginal discs at three time points during development: late third-instar larvae (L3), pupae approximately 6 hours after puparium formation (P6) and pupae approximately 20 hours after puparium formation (P20). We identified genes that are sex-differentially expressed in the developing genital disc, including three genes encoding transcription factors that are expressed in the genital disc of one sex but not the other. Through genetic analysis, we showed how the master regulator of sexual identity, Doublesex, limits expression of each of these three genes to one sex. We also determined which genital structures fail to develop properly in the absence of each of the three genes.