Project description:Anorexia nervosa (AN), bulimia nervosa (BN), and obsessive-compulsive disorder (OCD) are complex psychiatric disorders with shared obsessive features, thought to arise from the interaction of multiple genes of small effect with environmental factors. Potential candidate genes for AN, BN, and OCD have been identified through clinical association and neuroimaging studies; however, recent genome-wide association studies of eating disorders (ED) so far have failed to report significant findings. Additionally, few if any studies have interrogated postmortem brain tissue for evidence of eQTLs associated with candidate genes, which has particular promise as an approach to elucidating molecular mechanisms of association. We therefore selected single nucleotide polymorphisms (SNPs) based on candidate gene studies for AN, BN, and OCD from the literature, and examined the association of these SNPs with gene expression across the lifespan in prefrontal cortex of a non-psychiatric control cohort (N=268). Several risk-predisposing SNPs were significantly associated with gene expression among control subjects. We then measured gene expression in the prefrontal cortex of cases previously diagnosed with obsessive psychiatric disorders, e.g., eating disorders (ED; N=15), and obsessive-compulsive disorder/obsessive-compulsive personality disorder or tics (OCD/OCPD/Tic; N=16), and non-psychiatric controls (N=102) and identified 6 and 286 genes that were differentially expressed between ED compared to controls and OCD cases compared to controls, respectively (FDR < 5%). However, none of the clinical risk SNPs were among the eQTLs and none were significantly associated with gene expression within the broad obsessive cohort, suggesting larger sample sizes or other brain regions may be required to identify candidate molecular mechanisms of clinical association in postmortem brain datasets. Gene expression data from the dorsolateral prefrontal cortex (DLPFC) from postmortem tissue on 133 subjects - 15 eating disorder (ED) patients, 16 obessive compulsive disorder (OCD) patients, and 102 non-psychiatric controls - run on the Illumina HumanHT-12 v3 microarray
Project description:Anorexia nervosa (AN), bulimia nervosa (BN), and obsessive-compulsive disorder (OCD) are complex psychiatric disorders with shared obsessive features, thought to arise from the interaction of multiple genes of small effect with environmental factors. Potential candidate genes for AN, BN, and OCD have been identified through clinical association and neuroimaging studies; however, recent genome-wide association studies of eating disorders (ED) so far have failed to report significant findings. Additionally, few if any studies have interrogated postmortem brain tissue for evidence of eQTLs associated with candidate genes, which has particular promise as an approach to elucidating molecular mechanisms of association. We therefore selected single nucleotide polymorphisms (SNPs) based on candidate gene studies for AN, BN, and OCD from the literature, and examined the association of these SNPs with gene expression across the lifespan in prefrontal cortex of a non-psychiatric control cohort (N=268). Several risk-predisposing SNPs were significantly associated with gene expression among control subjects. We then measured gene expression in the prefrontal cortex of cases previously diagnosed with obsessive psychiatric disorders, e.g., eating disorders (ED; N=15), and obsessive-compulsive disorder/obsessive-compulsive personality disorder or tics (OCD/OCPD/Tic; N=16), and non-psychiatric controls (N=102) and identified 6 and 286 genes that were differentially expressed between ED compared to controls and OCD cases compared to controls, respectively (FDR < 5%). However, none of the clinical risk SNPs were among the eQTLs and none were significantly associated with gene expression within the broad obsessive cohort, suggesting larger sample sizes or other brain regions may be required to identify candidate molecular mechanisms of clinical association in postmortem brain datasets.
Project description:Genetic analysis of gene expression level is a promising approach for characterizing candidate genes that are involved in complex economic traits such as meat quality. In the present study, we conducted expression quantitative trait loci (eQTL) and allele-specific expression (ASE) analyses based on RNA-sequencing (RNAseq) data from the longissimus muscle of 189 Duroc × Luchuan crossed pigs in order to identify some candidate genes for meat quality traits. Using a genome-wide association study based on a fixed linear model, we identified 7,192 cis-eQTL corresponding to 2,098 cis-genes (p ≤ 1.33e-3, FDR ≤ 0.05) and 6,400 trans-eQTL corresponding to 863 trans-genes (p ≤ 1.13e-6, FDR ≤ 0.05). ASE analysis using RNAseq SNPs identified 9,815 significant ASE-SNPs in 2,253 unique genes. Integrative analysis between the cis-eQTL and ASE target genes identified 540 common genes, including 33 genes with expression levels that were correlated with at least one meat quality trait. Among these 540 common genes, 63 have been reported previously as candidate genes for meat quality traits, such as PHKG1 (q-value = 1.67e-6 for the leading SNP in the cis-eQTL analysis), NUDT7 (q-value = 5.67e-13), FADS2 (q-value = 8.44e-5), and DGAT2 (q-value = 1.24e-3).This study provides valuable information on the genetics of gene expression in porcine skeletal muscle. The characterized cis-genes and ASE genes, combined with the correlations between gene expression level and meat quality traits will be useful to prioritize candidate genes in further studies.
2019-06-24 | GSE124315 | GEO
Project description:Replicating association signals between candidate SNPs and admixed Brazilian patients with Genetic Generalized Epilepsy
Project description:Sequence and transcriptional variability within and between individuals are typically studied independently. The joint analysis of sequence and gene expression variation provides insight into biological mechanisms that underlie gene regulation and function. We investigated the role of sequence variation in cis on gene expression (cis sequence effects) in a group of genes frequently studied in cancer research. We assessed the proportion of genes exhibiting cis sequence effects and the proportion of gene expression variation explained by cis sequence effects, and compared our results to the literature. Keywords: genetical genomics Thirty lymphoblastoid cell lines drawn from the SNP500Cancer resource were cultured in triplicate. The intersection of gene expression profiling data at N=697 candidate genes and genomic sequencing data at N=552 candidate genes from these cell lines yielded data at thirty candidate genes with strong and variable gene expression suitable for the investigation of cis sequence effects. We used regression on SNP genotype in an additive model, the single-point additive model of Mander, and the haplotype phylogeny scanning approach of Templeton to evaluate associations between individual SNPs, all SNPs at a gene, and diplotypes, with log-transformed and rank-invariant normalized mean gene expression. SNPs and diplotypes at eight candidate genes exhibited statistically significant (p<0.05) association with gene expression using one or more methods. Data were available for fourteen candidate genes common to the literature and our analysis, five of which exhibited significant cis effects in this study. Using the literature results as a M-bM-^@M-^\gold standardM-bM-^@M-^], and after excluding two genes that exhibited discordant literature results, our study concordantly identified 4 of 5 genes, and 6 of 7 genes as exhibiting and not exhibiting significant cis sequence effects, respectively.
Project description:The genomic distribution of trait-associated SNPs (TASs) discovered in genome-wide association studies (GWAS) can provide insight into the genetic architecture of complex traits and the design of future studies. Here we report on a maize GWAS that identified TASs underlying five quantitative traits measured across a large panel of samples and examine the characteristics of these TASs. A set of SNPs obtained via RNA sequencing (RNA-seq), most of which are located within annotated genes (~87%) were complemented with additional SNPs from the maize HapMap Project that contains approximately equal proportions of intragenic and intergenic SNPs. TASs were identified via a genome scan while controlling for polygenic background effects. The diverse functions of TAS-containing candidate genes indicate that complex genetic networks shape these traits. The vast majority of the TAS-containing candidate genes have dynamic expression levels among developmental stages. Overall, TASs explain 44~54% of the total phenotypic variation for these traits, with equal contributions from intra- and inter-genic TASs. Association of ligueless2 with upper leaf angle was implicated by two intragenic TASs; rough sheath1 was associated with leaf width by an upstream intergenic TAS; and Zea agamous5 was associated with days to silking by both intra- and inter-genic TASs. A large proportion (82%) of these TASs comes from noncoding regions, similar to findings from human diseases and traits. However, TASs were enriched in both intergenic (53%) and promoter 5kb (24%) regions, but under-represented in a set of nonsynonymous SNPs.
Project description:A GWAS study was then performed in 52 non-adhesive and 68 strong adhesive pigs for F4ab/ac ETEC originating from 5 Belgian farms. A new refined candidate region (chr13: 144,810,100-144,993,222) for F4ac ETEC susceptibility was identified with MUC13 adjacent to the distal part of the region. All pigs were phenotyped for the presence of the F4ab/ac receptor (F4ab/acR) using the in vitro villous adhesion assay with 4×108 F4ac E. coli (strain GIS26, serotype O149:K91, F4ac+) or F4ab E. coli (strain G7, serotype O8:K87, F4ab+) . A total of 120 F4ab/acR phenotyped pigs were genotyped using the Porcine SNP60 BeadChip (Illumina) containing 62,163 SNPs, according to the manufacturer’s protocol. The position of the SNPs was based on the current pig genome assembly (Sscrofa10.2).
Project description:Alpine goat phenotypes for quality components have been routinely recorded for many years and deposited in the Council on Dairy Cattle Breeding (CDCB) repository. The data collected were used to conduct an exploratory genome-wide association study (GWAS) from 72 female Alpine goats originating from locations throughout the U.S. Genotypes were identified with the Illumina Goat 50K single nucleotide polymorphisms (SNP) Beadchip. The analysis used a polygenic model where the dropping criteria was the Call Rate ≥ 0.95. The initial dataset was composed of ~ 60,000 rows of SNPs, 21 columns of phenotypic traits and composed of 53,384 scaffolds containing other informative data points used for genomic predictive power. Phenotypic association with the 50KBeadchip revealed 26,074 reads of candidate genes. These candidate genes segregated as separate novel SNPs and were identified as statistically significant regions for genome and chromosome level trait associations. Candidate genes associated differently for each of the following phenotypic traits: test day milk yield (13,469 candidate genes), test day protein yield (25,690 candidate genes), test day fat yield (25,690 candidate genes), percentage protein (25,690 candidate genes), percentage fat (25,690 candidate genes), and percentage lactose content (25,690 candidate genes). The outcome of this study supports elucidation of novel genes that are important for livestock species in association to key phenotypic traits. Validation towards the development of marker-based selection that provide precision breeding methods will thereby increase breeding value. Specific aims: 1) Improve on contributions to the phenotype repository, the Council on Dairy Cattle Breeding (CDCB) for milk quality traits that are economically important for goat production while developing a corresponding DNA repository for each of the animals with significant genotype-phenotype associations. 2) Develop genomic prediction tools and provide data for a better database for tools to predict phenotypic traits by initially using the high density Goat50KSNP BeadChip for the selection of more specific SNPs associated with select signatures (genes) for phenotypic traits in American Alpine goats. 3) To establish whether a low number of goat subjects (< 300 goats) will provide statistically significant (p < 0.05) predictive capabilities for desired breeding traits in American Alpine dairy goats.