Project description:We used microarrays and a previously established linkage map to localize the genetic determinants of brain gene expression for a backcross family of lake whitefish species pairs (Coregonus sp.). Our goals were to elucidate the genomic distribution and sex-specificity of brain expression QTL (eQTL) and to determine the extent to which genes controlling transcriptional variation may underlie adaptive divergence in the recently evolved dwarf (limnetic) and normal (benthic) whitefish. We observed a sex-bias in transcriptional genetic architecture, with more eQTL observed in males, as well as divergence in genome location of eQTL between sexes. Hotspots of nonrandom aggregations of up to 32 eQTL in one location were observed. We identified candidate genes for species pair divergence involved with energetic metabolism, protein synthesis, and neural development based on co-localization of eQTL for these genes with eight previously identified adaptive phenotypic QTL and four previously identified outlier loci from a genome scan in natural populations. 88% of eQTL-phenotypic QTL co-localization involved growth rate and condition factor QTL, two traits central to adaptive divergence between whitefish species pairs. Hotspots co-localized with phenotypic QTL in several cases, revealing possible locations where master regulatory genes, such as a zinc finger protein in one case, control gene expression directly related to adaptive phenotypic divergence. We observed little evidence of co-localization of brain eQTL with behavioral QTL, which provides insight on the genes identified by behavioral QTL studies. These results extend to the transcriptome level previous work illustrating that selection has shaped recent parallel divergence between dwarf and normal lake whitefish species pairs and that metabolic, more than morphological differences appear to play a key role in this divergence. Keywords: eQTL mapping, gene expression, linkage mapping, adaptive radiation, Coregonus, microarrays
Project description:We used microarrays and a previously established linkage map to localize the genetic determinants of brain gene expression for a backcross family of lake whitefish species pairs (Coregonus sp.). Our goals were to elucidate the genomic distribution and sex-specificity of brain expression QTL (eQTL) and to determine the extent to which genes controlling transcriptional variation may underlie adaptive divergence in the recently evolved dwarf (limnetic) and normal (benthic) whitefish. We observed a sex-bias in transcriptional genetic architecture, with more eQTL observed in males, as well as divergence in genome location of eQTL between sexes. Hotspots of nonrandom aggregations of up to 32 eQTL in one location were observed. We identified candidate genes for species pair divergence involved with energetic metabolism, protein synthesis, and neural development based on co-localization of eQTL for these genes with eight previously identified adaptive phenotypic QTL and four previously identified outlier loci from a genome scan in natural populations. 88% of eQTL-phenotypic QTL co-localization involved growth rate and condition factor QTL, two traits central to adaptive divergence between whitefish species pairs. Hotspots co-localized with phenotypic QTL in several cases, revealing possible locations where master regulatory genes, such as a zinc finger protein in one case, control gene expression directly related to adaptive phenotypic divergence. We observed little evidence of co-localization of brain eQTL with behavioral QTL, which provides insight on the genes identified by behavioral QTL studies. These results extend to the transcriptome level previous work illustrating that selection has shaped recent parallel divergence between dwarf and normal lake whitefish species pairs and that metabolic, more than morphological differences appear to play a key role in this divergence. Keywords: eQTL mapping, gene expression, linkage mapping, adaptive radiation, Coregonus, microarrays The objective of this study was to elucidate the genomic distribution and sex-specificity of brain eQTL in dwarf and normal lake whitefish. Dissected brain tissue (250-350 mg) was sampled for 55 individuals from a hybrid x dwarf backcross mapping family. We used a loop design (YANG and SPEED 2002; CHURCHILL 2002) to maximize the number of sampled meioses. Each of 55 samples was technically replicated on two distinct slides, while performing dye swapping (Cy3 and Alexa) to estimate the dye intensity variation bias. After correcting for local background, raw intensity values were both log2 transformed and normalized using the regional LOWESS method implemented in the R/MANOVA software (KERR et al. 2000). We used a previously generated linkage map based on the same backcross individuals for which gene expression was measured. eQTL mapping was performed with QTL Cartographer.
Project description:Single-nucleus RNA sequencing (snRNA-seq) was used to profile the transcriptome of 8,413 nuclei in chicken adult testis. This dataset includes two samples from two different individuals. This dataset is part of a larger evolutionary study of adult testis at the single-nucleus level (97,521 single-nuclei in total) across mammals including 10 representatives of the three main mammalian lineages: human, chimpanzee, bonobo, gorilla, gibbon, rhesus macaque, marmoset, mouse (placental mammals); grey short-tailed opossum (marsupials); and platypus (egg-laying monotremes). Corresponding data were generated for a bird (red junglefowl, the progenitor of domestic chicken), to be used as an evolutionary outgroup.
Project description:A minor population of M cells within the follicle-associated epithelium (FAE) of intestinal Peyer’s patches (PP) serves as a major portal for entry of exogenous antigens. Characterization of the mammalian M cells, including identification of M-cell surface molecules used for bacterial uptake, has been hampered by their relative rarity. In contrast, M cells constitute virtually all of the FAE cells in the avian bursa of Fabricius. We therefore performed comparative gene expression profiling of chicken and murine FAE to identify commonly expressed genes by M cells in both species. The comprehensive transcriptome analysis revealed that 28 genes were commonly up-regulated in FAE from both species. In situ hybridization (ISH) revealed that annexin A10 (Anxa10) mRNA was scattered in FAE, and co-localized with Ulex europaeus agglutinin-1(UEA-1) that binds to M cells. Whole-mount immunostaining also revealed that cellular prion protein (PrPC) was expressed on the luminal side of the apical plasma membrane of M cells, and co-localized with grycoprotein2 (GP2) that recognizes only M cells in murine PP. Taken together, we found new M-cell-specific molecules by using comprehensive transcriptome analysis. These molecules conserved in M cells from both species might play critical roles in M-cell function and/or differentiation.
Project description:Relative expression levels of mRNAs in chicken cecal epithelia experimentally infected with Eimeria tenella were measured at 4.5 days post-infection. Two weeks old chickens were uninfected (negative control) or were orally inoculated with sporulated oocysts of Eimeria tenella. Cecal epithelia samples were collected from >12 birds in infected or uninfected group at 4.5 d following infections, in which samples from 4 birds were pooled together to form a total 3 biological replicates in each group. Parasite merozoites were also collected from four infected chickens at 5 d after infections. Uninfected control samples, merozoites and infection group samples were selected for RNA extraction and hybridization on Affymetrix microarrays. We used Affymetrix GeneChip chicken genome arrays to detail the chicken cecal epithelia gene expression in the control and E. tenella-infected birds. Infected, uninfected chicken cecal epithelia and merozoites were selected for RNA extraction and hybridization with Affymetrix microarrays. Our goal was to analyze global transcriptome changes in chicken cecal mucous membranes in response to E. tenella infection in vivo. We used infected (T1,T2,T3; three biological replicates) and uninfected (Neg1, Neg2, Neg3; three biological replicates) samples to identify genes that were differentially expressed. Meanwhile, RNA and probes were also prepared from parasite merozoites (Mzt) from infected samples (Mzt) and used as an additional control in microarray hybridization.
Project description:Relative expression levels of mRNAs in chicken cecal epithelia experimentally infected with Eimeria tenella were measured at 4.5 days post-infection. Two weeks old chickens were uninfected (negative control) or were orally inoculated with sporulated oocysts of Eimeria tenella. Cecal epithelia samples were collected from >12 birds in infected or uninfected group at 4.5 d following infections, in which samples from 4 birds were pooled together to form a total 3 biological replicates in each group. Parasite merozoites were also collected from four infected chickens at 5 d after infections. Uninfected control samples, merozoites and infection group samples were selected for RNA extraction and hybridization on Affymetrix microarrays. We used Affymetrix GeneChip chicken genome arrays to detail the chicken cecal epithelia gene expression in the control and E. tenella-infected birds.
Project description:The existence of conventional dendritic cells (cDCs) has not yet been demonstrated outside mammals. In this paper, we identified bona fide cDCs in chicken spleen. Comparative profiling of global and of immune response gene expression, morphology, and T cell activation properties show that cDCs and macrophages (MPs) exist as distinct mononuclear phagocytes in chicken, resembling their human and mouse cell counterparts. Using computational analysis, core gene expression signatures for cDCs, MPs, T and B cells across chicken, human and mouse were established, which will facilitate the identification of these subsets in other vertebrates. Overall this study, by extending the newly uncovered cDC and MP paradigm to chicken, suggests that the generation of these two phagocyte lineages occurred before the reptile to mammal and bird transition in evolution. It opens avenues for the design of new vaccines and neutraceuticals that are mandatory for the sustained supply of poultry products in the expanding human population.
Project description:Global transcriptome profiling of leaf tissue from 100 RILs. All plants were field-grown and infected with GLS. Objective was to carry out systems genetics of the transcriptional responses to GLS, by overlaying results obtained from co-expression correlation analysis, eQTL analysis and QTL analysis.