SeqControl: Process Control for DNA Sequencing
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ABSTRACT:
PROVIDER: EGAS00001000899 | EGA |
REPOSITORIES: EGA
Similar Datasets
Project description:The objective of this study is to optimize the search by next-generation sequencing (NGS) mutations in the KRAS, BRAF and NRAS on circulating tumor DNA and compare the genetic profiles obtained with those from tumors embedded in paraffin
| 2219385 | ecrin-mdr-crc
Project description:We have established a certification system for antibodies to be used in chromatin immunoprecipitation assays coupled to massive parallel sequencing (ChIP-seq). This certification comprises a standardized ChIP procedure and the attribution of a numerical quality control indicator (QCi) to biological replicate experiments. The QCi computation is based on a universally applicable quality assessment that quantitates the global deviation of randomly sampled subsets of ChIP-seq dataset with the original genome-aligned sequence reads. Comparison with a QCi database for >28,000 ChIP-seq assays were used to attribute quality grades (ranging from âAAAâ to âDDDâ) to a given dataset. In the present report we used the numerical QC system to assess the factors influencing the quality of ChIP-seq assays, including the nature of the target, the sequencing depth and the commercial source of the antibody. We have used this approach specifically to certify mono and polyclonal antibodies obtained from Active Motif directed against the histone modification marks H3K4me3, H3K27ac and H3K9ac for ChIP-seq. The antibodies received the grades AAA to BBA (www.ngs-qc.org). We propose to attribute such quantitative grading of all antibodies attributed with the label âChIP-seq gradeâ. The NGS-QC team has setup a certification procedure for Antibodies dedicated to ChIP-seq applications based on (1)a highly reproducible pipeline for performing ChIP-seq assays including the use of an automated liquid handling platform (TECAN EVO75) for ChIP and sequencing library preparation steps and (2) the use of the NGS-QC Generator tool for providing a ChIP-seq quality grade and to evaluate other parameters like the Optimal sequencing depth, the degree of reproducibility among biological replicates and the comparison of the quality grades of the certified antibody with datasets retrieved in the public domain. This quality certification structure makes possible to assign a measured Quality Stamp to ChIP-seq grade Antibodies.
2016-01-07 | E-GEOD-76618 | biostudies-arrayexpress
Project description:Deep high-throughput transcriptome sequencing (RNA-seq) performed on 3 pairs of matched tumor and adjacent non-tumorours (NT) tissues from HCC patients of Chinese origin generated 183.6-million reads that could be aligned. We discovered a number of differentially expressed genes and multiple types of somatic single nucleotide variations (SNVs) in expressed genes. After the removal of the error alignments, high-quality reads were mapped to the human reference sequence (GRCh37/hg19) using three different softwares TopHat, Burrows-Wheeler Aligner (BWA) and CLC Genomics Workbench (CLC). The high-quality variants were identified using VarScan with the following parameters: minimum coverage depth of 10, variation frequency of more than 30% and base quality of more than 15. A total of 568, 545 and 494 potential somatic single nucleotide variants (SNVs), including 94, 89 and 101 coding somatic SNVs (cSNVs), were identified in 3 tumor samples HCC448T, HCC473T and HCC510T, respectively. Validation analysis was carried out for 10 of the intersected cSNVs (all are non-synonymous substitutions) within selected genes of interests with the majority confirmed. Examination of 3 paired human hepatocellular carcinoma and matched non-tumor tissues
2013-04-02 | E-GEOD-33294 | biostudies-arrayexpress
Project description:Deep high-throughput transcriptome sequencing (RNA-seq) performed on 3 pairs of matched tumor and adjacent non-tumorours (NT) tissues from HCC patients of Chinese origin generated 183.6-million reads that could be aligned. We discovered a number of differentially expressed genes and multiple types of somatic single nucleotide variations (SNVs) in expressed genes. After the removal of the error alignments, high-quality reads were mapped to the human reference sequence (GRCh37/hg19) using three different softwares TopHat, Burrows-Wheeler Aligner (BWA) and CLC Genomics Workbench (CLC). The high-quality variants were identified using VarScan with the following parameters: minimum coverage depth of 10, variation frequency of more than 30% and base quality of more than 15. A total of 568, 545 and 494 potential somatic single nucleotide variants (SNVs), including 94, 89 and 101 coding somatic SNVs (cSNVs), were identified in 3 tumor samples HCC448T, HCC473T and HCC510T, respectively. Validation analysis was carried out for 10 of the intersected cSNVs (all are non-synonymous substitutions) within selected genes of interests with the majority confirmed.
2013-04-02 | GSE33294 | GEO
Project description:Next generation sequencing platforms have become essential tools for understanding DNA in a wide range of contexts. Their success heavily relies on the accuracy, sensitivity and specificity of methods used to discern differences between the reference genome and genomes under investigation. Here we compare the relative performances of five popular single nucleotide variant callers with and without their associated recommended hard filtering criteria. We compare: FreeBayes; the Genome Analysis Toolkit’s Haplotype Caller and Unified Genotyper; SAMtools; and VarScan. We tailor this comparison to suit smaller projects with modest sample numbers (n = 10) and coverage (~10X) to fill a current gap in the literature. Other comparison studies are generally applicable only to larger projects in model species, where there is access to large amounts of sequencing data and curated callsets for base and variant quality score recalibration. We estimated the accuracy, sensitivity and specificity of each pipeline according to the genotype concordance rate and number with the “truth” dataset for 10 canine samples. The truth dataset was defined as genotypes obtained from the CanineHD BeadChip array. Whole genome sequencing data was performed on the Illumina HiSeq2000 or HiSeq2500 platform as 100-101 base pair, paired end reads to an average sample coverage of 10.3X. Apart from GATK Haplotype Caller, applying recommended hard filters did not improve the performance of genotyping concordance at the tested levels of minimum coverage. The default VarScan pipeline with no additional filters applied (VarScan uses SAMtools mpileup, without base alignment quality computation) generally outperformed other callers in terms of accuracy, sensitivity and specificity. The results of this study demonstrate that hard filtering of variant calls from low-powered genome studies can impair accuracy, sensitivity and specificity of callsets and provides some benchmark performance metrics on a range of low coverage levels.
2018-08-31 | GSE117010 | GEO
Project description:The continuing ‘desire’ in obtaining more quantitative and detailed information from cellular proteomics experiments in regards to proteome coverage and protein modifications asks for a systematic investigation of the protein extraction and digestion protocols, in particular when working with unicellular organisms with a strong cell wall such as the model yeast S. cerevisiae. The selection of a suitable sample preparation workflow is crucial to obtain in-depth proteome coverage, as the use of certain sample preparation protocols may bias the protein identification or induce (unexpected) peptide modifications. Here, we made an extensive comparison of preparation workflows commonly applied to S. cerevisiae. Workflows were compared on the basis of identified MS/MS spectra, peptide sequences and number and type of modifications using both restricted (Peaks) and unrestricted (TagGraph) database search approaches. The proteome coverage was mainly affected by the sample collection approach, while it was maximized using a FASP. Extensive reagent specific peptide modifications were detected when using formic acid, but also when using acetone. Such artefacts split the analyte mass signals and generate additional chemical noise that may also elute differently compared to the native peptide. The use of both an unrestricted and restricted database search increased identification rates significantly and resulted in the identification of approximately 70% of the MS2 spectra for the best protocol. The unidentified spectra were assessed by their de novo sequencing score. This confirmed that those spectra consisted by a majority of very low quality spectra, insufficient to match to database sequences. However, a small fraction of the unidentified spectra showed high quality, which presumably derive from unknown sequence variants not present in the database. This study demonstrates the high importance of the sample preparation workflow and the obtained results will guide researchers in the field to optimize sample preparation procedures.
2022-03-31 | PXD026806 | Pride
Project description:Most proteogenomic approaches for mapping single amino acid polymorphisms (SAPs) require construction of a sample-specific database containing protein variants predicted from the next-generation sequencing (NGS) data. We present a new strategy for direct SAP detection without relying on NGS data. Among the 348 putative SAP peptides identified in an industrial yeast strain, 85.6% of SAP sites were validated by genomic sequencing.
2018-04-18 | PXD003101 | Pride
Project description:We report the transcriptome profiles (RNA seq) of three different co-isolates of S.aureus that have been identified and isolated in both laboratory and infective scenarios. The transcriptome profiles were generated by deep sequencing and transcript levels assessed. For this the raw reads underwent quality-trimming (using the FastX suite), polyA-clipping, size filtering, mapping to the reference genome, coverage calculation, gene wise expression quantification followed by differential gene expression analysis (all done by the tool "READemption" (Förstner et al., unpublished) using "segemehl" (Hoffmann et al., 2009) and "DESeq" (Anders et al., 2010). RT-PCR as well as phenotypical assays were further used to validate the data. Differential gene expression between the isolates was observed in 4% (116 of 2774 genes). This had a significant impact on the physiology of each strain. RNA profiles of 3 different subpopulations of S.aureus generated by deep sequencing
2014-10-13 | E-GEOD-49636 | biostudies-arrayexpress
Project description:To address how genetic variation alters gene expression in complex cell mixtures, we developed Direct Nuclear Tagmentation and RNA-sequencing (DNTR-seq), which enables whole genome and mRNA sequencing jointly in single cells. DNTR-seq readily identified minor subclones within leukemia patients. In a large-scale DNA damage screen, DNTR-seq was used to detect regions under purifying selection, and identified genes where mRNA abundance was resistant to copy number alteration, suggesting strong genetic compensation. mRNA-seq quality equals RNA-only methods, and the low positional bias of genomic libraries allowed detection of sub-megabase aberrations at ultra-low coverage. Each cell library is individually addressable and can be re-sequenced at increased depth, allowing multi-tiered study designs. Additionally, the direct tagmentation protocol enables coverage-independent estimation of ploidy, which can be used to identify cell singlets. Thus, DNTR-seq directly links each cell?s state to its corresponding genome at scale, enabling routine analysis of heterogeneous tumors and other complex tissues.
2020-10-22 | GSE144296 | GEO
Project description:<p>Next Generation Sequencing (NGS) technologies are being used for detection of somatic mutations in tumors and studies of germline variation. However, most NGS studies used DNA isolated either from whole blood or fresh frozen tissue specimens. Meanwhile, the tissue specimens available from most National Cancer Institute (NCI) funded cohorts and the Surveillance, Epidemiology and End Results (SEER) registries (<a href="http://seer.cancer.gov/biospecimen">http://seer.cancer.gov/biospecimen</a>) are primarily formalin fixed paraffin embedded (FFPE). There are limited data, on a small number of FFPE tissue samples, which suggest NGS is feasible. Much less is known about the feasibility of these technologies for large scale studies or using older FFPE specimens (e.g. 5-30 years old).</p> <p>The SEER cancer registries cover approximately 28% of the United States population, providing high quality demographic, clinical, pathologic, and survival data. The SEER Residual Tissue Repository (RTR) program was established in 2003. The RTR maintains biospecimens obtained from three of SEER' population-based cancer registries: Iowa, Hawaii, and Los Angeles. Investigators at government, academic, and nonprofit institutions may apply to the program to obtain annotated FFPE tumor tissue specimens to study biomarkers, etiology, and other aspects with a population-based sample of cancer cases. </p> <p>The main objective of this project was to conduct a pilot study to determine whether the DNA obtained from archival FFPE tissue from 3 SEER Registries is of sufficient quality and quantity to conduct NGS. For Exome sequencing, sixty high-grade serous ovarian adenocarcinomas from FFPE tissues which were between 7 and 31 years old were obtained from three SEER registries. DNA was extracted, quantified, quality assessed, and subjected to whole exome sequencing. DNA extraction (yields and quality) and whole exome sequencing (depths of coverage and exome coverage obtained) results from this study will be presented. For RNA-sequencing, sixty-seven high-grade serous ovarian adenocarcinomas from FFPE tissues which were between 7 and 31 years old were obtained from three SEER registries. Total RNA was extracted, quantified, quality assessed, and subjected to whole transcriptome sequencing. Ultimately data derived from this analysis could serve as the basis for determining the utility of archival FFPE biospecimens for characterization and discovery projects utilizing NGS technologies instead of relying on frozen biospecimens. </p>
| phs000950 | dbGaP