Project description:Transcriptional profiling of 3 day old virgin male and female adults comparing control male Drosophila melanogaster (MDM) versus male D sechellia (MDS) and comparing control female Drosophila melanogaster (FDM) versus female D sechellia (FDS). Goal was to determine why D sechellia is tolerant to octanoïc acid, the major toxic compound of Morinda citrifolia fruit
Project description:The dietary specialist fruit fly Drosophila sechellia evolved to feed primarily on the toxic fruit of Morinda citrifolia. Seeking the basis of adaptations to the unique chemistry of its host plant, we profiled genome-wide gene expression response to L-DOPA because it is highly abundant in M. citrifolia, critical for reproductive success of D. sechellia, and may influence toxin resistance in this species. Here we used a combination of functional genetics and genomics to identify a new gene, Esterase 6 (Est6) that is important for D. sechellia ecological adaptation to this new niche.
Project description:Drosophila sechellia is an island endemic host specialist that has evolved to consume the toxic fruit of Morinda citrifolia, also known as noni fruit. Recent studies by our group and others have examined genome-wide gene expression responses of fruit flies to individual highly abundant compounds found in noni responsible for the fruit’s unique chemistry and toxicity. In order to relate these reductionist experiments to the gene expression responses to feeding on noni fruit itself, we fed rotten noni fruit to adult female D. sechellia and performed RNA-sequencing. Combining the reductionist and more wholistic approaches, we have identified candidate genes that may contribute to each individual compound and those that play a more general role in response to the fruit as a whole. Using the compound specific and general responses, we used transcription factor prediction analyses to identify the regulatory networks and specific regulators involved in the responses to each compound and the fruit itself. The identified genes and regulators represent the possible genetic mechanisms and biochemical pathways that contribute to toxin resistance and noni specialization in D. sechellia.
Project description:We identified 6,975 insertion/deletion events of between 10 and 100 bp in length from the Drosophila simulans and Drosophila sechellia Mercator/MAVID genomic sequence alignment. Replicate pure samples of Drosophila simulans and Drosophila sechellia gDNA were competitively hybridized to measure the expected relative hybridization intensity of alleles from each species. We used these measured intensities to assess the likelihood that the hybridization signal at each probe in an experimental animal reflected homozygosity or heterozygosity at that locus.
Project description:We applied microfluidic multiplex PCR and deep sequencing (mmPCR-seq) to quantify RNA editing levels at targeted sites in Drosophila melanogaster, Drosophila sechellia and the species-specific alleles of their F1 hybrids to understand the contribution of cis and trans regulatory factors to regulating RNA editing levels.
Project description:We identified 6,975 insertion/deletion events of between 10 and 100 bp in length from the Drosophila simulans and Drosophila sechellia Mercator/MAVID genomic sequence alignment. Replicate pure samples of Drosophila simulans and Drosophila sechellia gDNA were competitively hybridized to measure the expected relative hybridization intensity of alleles from each species. We used these measured intensities to assess the likelihood that the hybridization signal at each probe in an experimental animal reflected homozygosity or heterozygosity at that locus. Indel array Agilent-022089 sim-sech.v.1.3
Project description:The dietary specialist fruit fly Drosophila sechellia has evolved to specialize on the toxic fruit of its host plant Morinda citrifolia. Toxicity of Morinda fruit is primarily due to high levels of octanoic acid (OA). Using RNA interference (RNAi), prior work found that knockdown of Osiris family genes Osiris 6 (Osi6), Osi7, and Osi8 led to increased susceptibility to OA in adult D. melanogaster flies, likely representing genes underlying a Quantitative Trait Locus (QTL) for OA resistance in D. sechellia. While genes in this major effect locus are beginning to be revealed, prior work has shown at least five regions of the genome contribute to OA resistance. Here, we identify new candidate OA resistance genes by performing differential gene expression analysis using RNA sequencing (RNA-seq) on control and OA-exposed D. sechellia flies. We found 104 significantly differentially expressed genes with annotated orthologs in D. melanogaster, including six Osiris gene family members, consistent with previous functional studies and gene expression analyses. Gene ontology (GO) term enrichment showed significant enrichment for cuticle development in upregulated genes and significant enrichment of immune and defense responses in downregulated genes suggesting important aspects of the physiology of D. sechellia that may play a role in OA resistance. In addition, we identified 5 candidate OA resistance genes that potentially underlie QTL peaks outside of the major effect region, representing promising new candidate genes for future functional studies.