Project description:The barley brittle stem mutants, fs2, designated X054 and M245, have reduced levels of cellulose compared with their isogenic parents Ohichi and Shiroseto. A custom-designed microarray, based on Agilent technology and including genes involved in cell wall metabolism, was used to compare transcript levels in the mutant and parental lines. For both mutants, the microarray revealed a marked decrease in mRNA for the HvCesA4 cellulose synthase gene in specific zones of stem internodes, and this was confirmed by quantitative PCR.
Project description:The barley brittle stem mutants, fs2, designated X054 and M245, have reduced levels of cellulose compared with their isogenic parents Ohichi and Shiroseto. A custom-designed microarray, based on Agilent technology and including genes involved in cell wall metabolism, was used to compare transcript levels in the mutant and parental lines. For both mutants, the microarray revealed a marked decrease in mRNA for the HvCesA4 cellulose synthase gene in specific zones of stem internodes, and this was confirmed by quantitative PCR. Genes expression was measured for the upper and lower zones from the 4th internodes of stems. Plant were at Zadocks developmental stage 49. Gene expression was compared between mutants and their wildtype parents.
Project description:In barley and other cereal crops, phenological diversity drives adaptation to different cultivation areas. Improvement of barley yield and quality traits requires adaptation to specific production areas with introgression of favorable alleles dependent upon precise identification of the underlying genes. Combining targeted sequence capture systems with next-generation sequencing provides an efficient approach to explore target genetic regions at high resolution, and allows rapid discovery of thousands of genetic polymorphisms. Here, we apply a versatile target-capture method to detect genome-wide polymorphisms in 174 flowering time-related genes, chosen based on prior knowledge from barley, rice, and Arabidopsis thaliana. Sequences were generated across a phenologically diverse panel of 895 barley varieties, resulting a high mean depth coverage of ~25x allowing reliable discovery and calling of insertion-deletion (InDel) and single nucleotide polymorphisms (SNPs). Sequences of InDel and SNPs from the targeted enrichment were utilized to develop 67 Kompetitive Allele Specific PCR (KASP) markers for validation. This work provides researchers and breeders a comprehensive molecular toolkit for the selection of phenology-related traits in barley.
Project description:Delta age is a biomarker of brain aging that captures differences between the chronological age and the predicted biological brain age. Using multimodal data of brain MRI, genomics, and blood-based biomarkers and metabolomics in UK Biobank, this study investigates an explainable and causal basis of high delta age. A visual saliency map of brain regions showed that lower volumes in the fornix and the lower part of the thalamus are key predictors of high delta age. Genome-wide association analysis of the delta age using the SNP array data identified associated variants in gene regions such as KLF3-AS1 and STX1. GWAS was also performed on the volumes in the fornix and the lower part of the thalamus, showing a high genetic correlation with delta age, indicating that they share a genetic basis. Mendelian randomization (MR) for all metabolomic biomarkers and blood-related phenotypes showed that immune-related phenotypes have a causal impact on increasing delta age. Our analysis revealed regions in the brain that are susceptible to the aging process and provided evidence of the causal and genetic connections between immune responses and brain aging.
Project description:Genetic studies in Tourette syndrome (TS) are characterized by scattered and poorly replicated findings. We aimed to replicate findings from candidate gene and genome-wide association studies (GWAS). Our cohort included 465 probands with chronic tic disorder (93% TS) and both parents from 412 families (some probands were siblings). We assessed 75 single nucleotide polymorphisms (SNPs) in 465 parent-child trios; 117 additional SNPs in 211 trios; and 4 additional SNPs in 254 trios. We performed SNP and gene-based transmission disequilibrium tests and compared nominally significant SNP results with those from a large independent case-control cohort. After quality control 71 SNPs were available in 371 trios; 112 SNPs in 179 trios; and 3 SNPs in 192 trios. 17 were candidate SNPs implicated in TS and 2 were implicated in obsessive-compulsive disorder (OCD) or autism spectrum disorder (ASD); 142 were tagging SNPs from eight monoamine neurotransmitter-related genes (including dopamine and serotonin); 10 were top SNPs from TS GWAS; and 13 top SNPs from attention-deficit/hyperactivity disorder, OCD, or ASD GWAS. None of the SNPs or genes reached significance after adjustment for multiple testing. We observed nominal significance for the candidate SNPs rs3744161 (TBCD) and rs4565946 (TPH2) and for five tagging SNPs; none of these showed significance in the independent cohort. Also, SLC1A1 in our gene-based analysis and two TS GWAS SNPs showed nominal significance, rs11603305 (intergenic) and rs621942 (PICALM). We found no convincing support for previously implicated genetic polymorphisms. Targeted re-sequencing should fully appreciate the relevance of candidate genes.
Project description:Plant stature in temperate cereals is predominantly controlled by tillering and plant height as complex agronomic traits, representing important determinants of grain yield. This study was designed to reveal the genetic basis of tillering at five developmental stages and plant height at harvest in 218 worldwide spring barley (Hordeum vulgare L.) accessions under greenhouse conditions. The accessions were structured based on row-type classes [two- vs. six-rowed] and photoperiod response [photoperiod-sensitive (Ppd-H1) vs. reduced photoperiod sensitivity (ppd-H1)]. Phenotypic analyses of both factors revealed profound between group effects on tiller development. To further verify the row-type effect on the studied traits, Six-rowed spike 1 (vrs1) mutants and their two-rowed progenitors were examined for tiller number per plant and plant height. Here, wild-type (Vrs1) plants were significantly taller and had more tillers than mutants suggesting a negative pleiotropic effect of this row-type locus on both traits. Our genome-wide association scans further revealed highly significant associations, thereby establishing a link between the genetic control of row-type, heading time, tillering, and plant height. We further show that associations for tillering and plant height are co-localized with chromosomal segments harboring known plant stature-related phytohormone and sugar-related genes. This work demonstrates the feasibility of the GWAS approach for identifying putative candidate genes for improving plant architecture.
Project description:Two genome-wide association studies (GWAS) identified the ?-microseminoprotein (MSMB) promoter SNP, rs10993994:C>T, as significantly associated with prostate cancer (PC) risk. Follow-up studies demonstrate that the variant allele directly affects expression of the MSMB-encoded protein, PSP94, and also suggest that it affects mRNA expression levels of an adjacent gene, NCOA4, which is involved in androgen receptor transactivation. In a population-based study of 1,323 cases and 1,268 age-matched controls, we found the NCOA4 SNP, rs7350420:T>C, was associated with a 15% reduction in PC risk, but the association was not significant after adjustment for the rs10993994:C>T genotype. Tumor tissue microarrays of 519 radical prostatectomy patients were used to measure PSP94 and NCOA4 protein expression. Taken together, these data confirm that the rs10993994:C>T variant allele is associated with decreased PSP94 expression, and the association is stronger in tumor compared to normal prostate tissue. No association was observed between rs10993994:C>T and NCOA4 expression, and only moderate associations were seen between two NCOA4 SNPs, rs10761618:T>C and rs7085433:G>A, and NCOA4 protein expression. These data indicate that the increase in PC risk associated with rs10993994:C>T is likely mediated by the variant's effect on PSP94 expression; however, this effect does not extend to NCOA4 in the data presented here.
Project description:Histone modifications are important markers of function and chromatin state, yet the DNA elements that direct them to specific locations in the genome are poorly understood. Here we use the genetic variation in Yoruba lymphoblastoid cell lines as a natural experiment to identify genetic differences that affect histone marks and to better understand their relationship with transcriptional regulation. Across the genome, we identified hundreds of quantitative trait loci that impact histone modification or RNA polymerase (PolII) occupancy. In many cases the same variant is associated with quantitative changes in multiple histone marks and PolII, as well as in DNaseI sensitivity and nucleosome positioning, indicating that these molecular phenotypes often share a single underlying genetic cause. Variants that impact chromatin at distal regulatory sites frequently also direct changes in chromatin and gene expression at associated promoters; while most of these distal regulators enhance promoter activity, some act as distal chromatin silencers. Finally, we find that polymorphisms in transcription factor binding sites are often causally responsible for variation in local histone modification. In summary, the class of variants identified here generate coordinated changes in chromatin both locally and sometimes at distant locations, frequently drive changes in gene expression, and likely play an important role in the genetics of complex traits. ChIP-seq of RNA Polymerase II and 4 histone modifications (H3K4me1, H3K4me3, H3K27ac, H3K27me3) in 10 unrelated Yoruba HapMap lymphoblastoid cell lines
Project description:We use targeted bisulfite PCR and next-generation 454 sequencing of multiple amplicons to analyze the association of cis-regulated allele-specific methylation (ASM) with multiple complex disease-associated variants in a population of 82 individuals. We detect ASM at four variants implicated in complex phenotypes such as ulcerative colitis and AIDS progression disease (rs10491434), Celiac disease (rs2762051), Crohn’s disease, IgA nephropathy and early-onset inflammatory bowel disease (rs713875) and height (rs6569648). 82 samples analysed