Project description:Long noncoding RNAs (lncRNAs) are a diverse class of RNAs that are critical for gene regulation, DNA repair and splicing, and have been implicated in cancer, stress response, and development. However, the function of many lncRNAs remains unknown. In Drosophila melanogaster, U snoRNA host gene 4 (Uhg4) encodes an antisense long noncoding RNA that is host to seven small nucleolar RNAs (snoRNAs). Uhg4 is expressed ubiquitously during development and in all adult fly tissues with maximal expression in ovaries; however, it has no annotated function(s). Here, we used CRISPR-Cas9 germline gene editing to generate multiple deletions spanning the promoter region and first exon of Uhg4. Mutant flies were sterile, showed delayed development and decreased viability, and changes in sleep and responses to stress. Whole genome RNA sequencing of Uhg4 deletion flies and their controls identified coregulated genes and genetic interaction networks. Gene ontology analyses highlighted a broad spectrum of biological processes, including morphogenesis, stress response, and regulation of transcription and translation. Thus, Uhg4 is a lncRNA essential for reproduction with pleiotropic effects on multiple fitness traits.
Project description:The abundance of transposable elements and DNA repeat sequences in mammalian genomes raises the question whether such insertions represent passive evolutionary baggage or may influence the expression of complex traits. We addressed this question in Drosophila melanogaster where the effects of single transposable elements on complex traits can be assessed in genetically identical individuals reared in controlled environments. Here we demonstrate that single P-element insertions in the intergenic region between the Gustatory receptor 5a (Gr5a) and Trapped in endoderm 1 (Tre1), which encodes an orphan receptor, exert complex pleiotropic effects on fitness traits, including selective nutrient intake, resistance to starvation and heat stress, and life span. Mutations in this region interact epistatically with downstream components of the insulin signaling pathway. Transposon-induced sex-specific and sex-antagonistic effects further accentuate the complex influences intergenic transposable elements can contribute to complex phenotypes. Keywords: Transcriptional profiles of P-element insertion lines in the Tre1/GR5a region of Drosophila
Project description:The abundance of transposable elements and DNA repeat sequences in mammalian genomes raises the question whether such insertions represent passive evolutionary baggage or may influence the expression of complex traits. We addressed this question in Drosophila melanogaster where the effects of single transposable elements on complex traits can be assessed in genetically identical individuals reared in controlled environments. Here we demonstrate that single P-element insertions in the intergenic region between the Gustatory receptor 5a (Gr5a) and Trapped in endoderm 1 (Tre1), which encodes an orphan receptor, exert complex pleiotropic effects on fitness traits, including selective nutrient intake, resistance to starvation and heat stress, and life span. Mutations in this region interact epistatically with downstream components of the insulin signaling pathway. Transposon-induced sex-specific and sex-antagonistic effects further accentuate the complex influences intergenic transposable elements can contribute to complex phenotypes. SUBMITTER_CITATION: Rollmann SM, Magwire MM, Morgan TJ, Ozsoy ED, Yamamoto A, Mackay TF, Anholt RR. Pleiotropic fitness effects of the Tre1-Gr5a region in Drosophila melanogaster. Nat Genet. 2006 Jul;38(7):824-9. Experiment Overall Design: BG02514, BG02257 and Canton S (B) lines were reared simultaneously at 25 C under a 12 h light/dark cycle and 70% humidity. At 5-7 days post-eclosion, we removed the heads of two replicate groups of 100 males and 100 females for each line. Total RNA was isolated from each replicate and biotinylated cRNA probes were hybridized to high density oligonucleotide microarrays (Affymetrix, Inc.) and visualized with a streptavidin-phycoerythrin conjugate, as described in the Affymetrix GeneChip Expression Analysis Technical Manual (2000), using internal references for quantification. The quantitative estimate of expression of each probe set is the Signal (Sig) metric, as described in the Affymetrix Microarray Suite, Version 5.0. Sig values were analyzed by two-way ANOVA according to the model Y = μ + L + S + LxS + E, where L is the effect of line, S is the effect of sex and E the error variance
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:Intralocus sexual conflict, where males and females have different fitness optima for the same trait, has been suggested to potentially be resolved by genomic imprinting, whereby expression in offspring is altered according to parent-of-origin. However, this idea has not yet been empirically tested. Here, we designed an experimental evolution protocol in Drosophila melanogaster which enabled us to look for imprinting effects on the X-chromosome. We enforced father-to-son transmission of the X-chromosome for many generations, and compared fitness and gene expression levels between control males, males with a control X-chromosome that had undergone one generation of father-son transmission (CDX), and males with an X-chromosome that had undergone many generations of father-son transmission (MLX). Although fitness differences were consistent with lowered fitness of males with a paternally inherited X-chromosome, expression differences suggested that this was due to deleterious maternal effects rather than imprinting. We conclude that imprinting is unlikely to resolve intralocus sexual conflict in Drosophila melanogaster.
Project description:Intralocus sexual conflict, where males and females have different fitness optima for the same trait, has been suggested to potentially be resolved by genomic imprinting, whereby expression in offspring is altered according to parent-of-origin. However, this idea has not yet been empirically tested. Here, we designed an experimental evolution protocol in Drosophila melanogaster which enabled us to look for imprinting effects on the X-chromosome. We enforced father-to-son transmission of the X-chromosome for many generations, and compared fitness and gene expression levels between control males, males with a control X-chromosome that had undergone one generation of father-son transmission (CDX), and males with an X-chromosome that had undergone many generations of father-son transmission (MLX). Although fitness differences were consistent with lowered fitness of males with a paternally inherited X-chromosome, expression differences suggested that this was due to deleterious maternal effects rather than imprinting. We conclude that imprinting is unlikely to resolve intralocus sexual conflict in Drosophila melanogaster. 18 samples were analyzed. There were 3 replicate populations within each of 3 treatments (Control, CDX, and MLX), and two males were analyzed from each population, for a total of 18 males.
Project description:This study examined the transcriptomic response of Drosophila melanogaster larvae to crowding conditions. The phenotypic and transcriptomic changes from low larval density (5 eggs/ml) to medium density (60 eggs/ml) were minor, yielding somewhat reduced adult fitness and only 24 differentially expressed genes (DEGs). In contrast, high density (300 eggs/ml) caused extensive detrimental effects on adult fitness and yielded 2107 DEGs. Among these, upregulated gene sets were enriched in sugar, steroid and amino acid metabolism as well as DNA replication pathways, whereas downregulated gene sets were enriched in ABC transporters, Taurine, Toll/Imd signalling and P450 xenobiotics metabolism pathways.
Project description:The notion that genes are the sole units of heredity and that a barrier exists between soma and germline has been a major hurdle in elucidating the heritability of traits that were observed to follow a non-Mendelian inheritance pattern. It was only after the conception of “epigenetics” by C. H. Waddington that the effect of parental environment on subsequent generations via non-DNA sequence-based mechanisms, such as DNA methylation, chromatin modifications, non-coding RNAs and proteins, could be established in various organisms, now referred to as multigenerational epigenetic inheritance. Despite the growing body of evidence, the male gamete-derived epigenetic factors that mediate the transmission of such phenotypes are seldom explored, particularly in the model organism Drosophila melanogaster. Using the heat stress-induced multigenerational epigenetic inheritance paradigm in a widely used position-effect variegation line of Drosophila, named white-mottled, we have dissected the effect of heat stress on the sperm proteome in the current study. We demonstrate that multiple successive generations of heat stress at the early embryonic stage results in a significant downregulation of proteins associated with translation, chromatin organization, microtubule-based processes, and generation of metabolites and energy in the Drosophila sperms. Based on our findings, we propose chromatin-based epigenetic mechanisms, a well-established mechanism for environmentally induced multigenerational effects, as a plausible way of transmitting heat stress memory via the male germ line in subsequent generations. Moreover, we demonstrate the effect of multiple generations of heat stress on the reproductive fitness of Drosophila, shedding light on the adaptive or maladaptive potential of heat stress-induced multigenerational phenotypes.