Project description:a comparison of brain gene expression patterns between several species pairs of domesticated and wild animals. Each pair consists of 5-6 wild and domesticated animals.
Project description:There is growing evidence for the prevalence of DNA copy number variation (CNV) and its role in phenotypic variation in recent years. Comparative genomic hybridization (CGH) was used to explore the extent of this type of structural variation in the barley genome. In a panel of 14 genotypes including domesticated cultivars and wild barleys, we found that 14.9% of all the sequences on the array are affected by CNV. Higher levels of CNV diversity are present in the wild accessions relative to cultivated barley. A substantial portion (37%) of the CNV events are present in both wild and domesticated barley. CNVs are enriched in telomeric regions for all chromosomes except 4H, which is also the barley chromosome with the lowest proportion of CNVs. CNV affected 9.5% of the coding sequences represented on the array. The genes affected by CNV are enriched for sequences annotated as disease-resistance proteins and protein kinases, suggesting the potential for CNV to influence variation for responses to biotic and abiotic stress. The analysis of CNV breakpoints indicated that DNA repair mechanisms of double-strand breaks (DSBs) via single-stranded annealing (SSA) and synthesis-dependent strand annealing (SDSA) play an important role in the origin of many structural changes in barley. Here we present the first catalog of CNVs in a diploid Triticeae species, which opens the door for future genome diversity research in a tribe that comprises the economically important cereal species wheat, barley and rye. Our findings constitute a valuable resource for the identification of CNV affecting genes of agronomic importance.
Project description:Persistent mucosal inflammation and microbial infection are characteristic of Chronic Rhinosinusitis (CRS). Though mucosal microbiota dysbiosis is a characteristic feature of other chronic inflammatory diseases, the relationship between sinus microbiota composition and CRS is unknown. Here we demonstrate, using comparative microbiome profiling of a cohort of CRS patients and healthy subjects, that the sinus microbiota of CRS patients exhibit significantly reduced bacterial diversity. Characteristic of this community collapse is the depletion of multiple, phylogenetically distinct, Lactic Acid Bacteria and the concomitant increase in relative abundance of a single species, Corynebacterium tuberculostearicum. Recapitulating the conditions observed in our human cohort in a murine model confirmed the pathogenic potential of C. tuberculostearicum and the critical necessity for a replete mucosal microbiota to protect against this species. Moreover, we provide evidence that Lactobacillus sakei, identified from our comparative microbiome analyses as a potentially protective species, affords defense against C. tuberculostearicum sinus infection, even in the context of a depleted sinus bacterial community. These studies demonstrate that sinus mucosal health is highly dependent on the composition of the resident microbiota, and identifies a new sino-pathogen and a strong bacterial candidate for therapeutic intervention. A total of 14 samples were profiled for microbiome composition: 7 from non-sinusitis patients, and 7 from patients with clinically diagnosed chronic sinusitis.
Project description:Microbiota-induced cytokine responses participate in gut homeostasis, but the cytokine balance at steady-state and the role of individual bacterial species in setting the balance remain elusive. Using gnotobiotic mouse models, we provide a systematic analysis of the role of microbiota in the induction of cytokine responses in the normal intestine. Colonization by a whole mouse microbiota orchestrated a broad spectrum of pro-inflammatory (Th1, Th17) and regulatory T cell responses. Unexpectedly, most tested complex microbiota and individual bacteria failed to efficiently stimulate intestinal cytokine responses. A potent cytokine-inducing function was however associated with non-culturable host-specific species, the prototype of which was the Clostridia-related Segmented Filamentous Bacterium, and this bacterial species recapitulated the coordinated maturation of T cell responses induced by the whole mouse microbiota. Our study demonstrates the non-redundant role of microbiota members in the regulation of gut immune homeostasis.
Project description:The rate, timing, and mode of species dispersal is recognized as a key driver of the structure and function of communities of macroorganisms, and may be one ecological process that determines the diversity of microbiomes. Many previous studies have quantified the modes and mechanisms of bacterial motility using monocultures of a few model bacterial species. But most microbes live in multispecies microbial communities, where direct interactions between microbes may inhibit or facilitate dispersal through a number of physical (e.g., hydrodynamic) and biological (e.g., chemotaxis) mechanisms, which remain largely unexplored. Using cheese rinds as a model microbiome, we demonstrate that physical networks created by filamentous fungi can impact the extent of small-scale bacterial dispersal and can shape the composition of microbiomes. From the cheese rind of Saint Nectaire, we serendipitously observed the bacterium Serratia proteamaculans actively spreads on networks formed by the fungus Mucor. By experimentally recreating these pairwise interactions in the lab, we show that Serratia spreads on actively growing and previously established fungal networks. The extent of symbiotic dispersal is dependent on the fungal network: diffuse and fast-growing Mucor networks provide the greatest dispersal facilitation of the Serratia species, while dense and slow-growing Penicillium networks provide limited dispersal facilitation. Fungal-mediated dispersal occurs in closely related Serratia species isolated from other environments, suggesting that this bacterial-fungal interaction is widespread in nature. Both RNA-seq and transposon mutagenesis point to specific molecular mechanisms that play key roles in this bacterial-fungal interaction, including chitin utilization and flagellin biosynthesis. By manipulating the presence and type of fungal networks in multispecies communities, we provide the first evidence that fungal networks shape the composition of bacterial communities, with Mucor networks shifting experimental bacterial communities to complete dominance by motile Proteobacteria. Collectively, our work demonstrates that these strong biophysical interactions between bacterial and fungi can have community-level consequences and may be operating in many other microbiomes.
Project description:Reactive oxygen species (ROS) play a prominent role in signal transduction and cellular homeostasis in plants. However, imbalances between generation and elimination of ROS can give rise to oxidative stress in growing cells. Because ROS are important to cell growth, ROS modulation could be responsive to natural or human-mediated selection pressure in plants. To study the evolution of oxidative stress related genes in a single plant cell, we conducted comparative expression profiling analyses of the elongated seed trichomes (‘‘fibers’’) of cotton (Gossypium), using a phylogenetic approach. We measured expression changes during diploid progenitor species divergence, allopolyploid formation and parallel domestication of diploid and allopolyploid species, using a microarray platform that interrogates 42,429 unigenes. The distribution of differentially expressed genes in progenitor diploid species revealed significant up-regulation of ROS scavenging and potential signaling processes in domesticated G. arboreum. Similarly, in two independently domesticated allopolyploid species (G. barbadense and G. hirsutum) antioxidant genes were substantially up-regulated in comparison to antecedent wild forms. In contrast, analyses of three wild allopolyploid species indicate that genomic merger and ancient allopolyploid formation had no significant influences on regulation of ROS related genes. Remarkably, many of the ROS-related processes diagnosed as possible targets of selection were shared among diploid and allopolyploid cultigens, but involved different sets of antioxidant genes. Our data suggests that parallel human selection for enhanced fiber growth in several geographically widely dispersed species of domesticated cotton resulted in similar and overlapping metabolic transformations of the manner in which cellular redox levels have become modulated. We measured expression changes during diploid progenitor species divergence, allopolyploid formation and parallel domestication of diploid and allopolyploid species, using a microarray platform that interrogates 42,429 unigenes. The distribution of differentially expressed genes was studied for domesticated G. arboreum and two independently domesticated allopolyploid species (G. barbadense and G. hirsutum). These were compared to three wild allopolyploid species. Three biological replicates were performed.
Project description:We explored the transcriptomic alterations associated with domestication by interrogating a developmental time course of cotton fibers from the wild G. hirsutum var. yucatanense and a representative of an elite domesticated line. 30 chip design - including 2 species (wild and domesticated cotton), by 1 tissue (fiber), for 5 timepoints (2,7,10,20, and 25 days after anthesis), with 3 replicates per timepoint