Project description:Background: Whole exome sequencing (WES) has been proven to serve as a valuable basis for various applications such as variant calling and copy number variation (CNV) analyses. For those analyses the read coverage should be optimally balanced throughout protein coding regions at sufficient read depth. Unfortunately, WES is known for its uneven coverage within coding regions due to GC-rich regions or off-target enrichment. Results: In order to examine the irregularities of WES within genes, we applied Agilent SureSelectXT exome capture on human samples and sequenced these via Illumina in 2x101 paired-end mode. As we suspected the sequenced insert length to be crucial in the uneven coverage of exome captured samples, we sheared 12 genomic DNA samples to two different DNA insert size lengths, namely 130 and 170 bp. Interestingly, although mean coverages of target regions were clearly higher in samples of 130 bp insert length, the level of evenness was more pronounced in 170 bp samples. Moreover, merging overlapping paired-end reads revealed a positive effect on evenness indicating overlapping reads as another reason for the unevenness. In addition, mutation analysis on a subset of the samples was performed. In these isogenic subclones almost twofold mutations were failed in the 130 bp samples when compared to the 170 bp samples. Visual inspection of the discarded mutation sites exposed low coverages at the sites embedded in high amplitudes of coverage depth in the affected region. Conclusions: Producing longer insert reads could be a good strategy to achieve better uniform read coverage in coding regions and hereby enhancing the effective sequencing yield to provide an improved basis for further variant calling and CNV analyses.
Project description:Ascites or solid tumour from patients with ovarian cancer was collected and grown in culture as ex vivo models. Each sample has a mixture of tumour and stromal cells which were separated into individual cultures. Therefore each patient has tumour and stromal cultures originating from the same tissue collection. Variant calling (exome-seq) analysis was performed on these matched models to establish tumour specific mutations. Stromal cells were used to rule out germline mutations.
Project description:The study included 15 patients (7 males, 8 females) with JMML. Peripheral blood and/or bone marrow aspirates were collected on EDTA at diagnosis. Non-hematopoietic tissues (fibroblasts) was derived from skin biopsy for each patient. Exome sequencing was performed in several distinct series between 2012 and 2017, which explains the differences in capture kit versions and reference genome version.Targeted enrichment and massive parallel sequencing were performed on paired genomic DNA from leukocytes and fibroblasts. Exome capture was carried out using the SureSelect Human All Exon V4+UTRs or V5 or V5+UTRs or SureSelect Clinical Research (Agilent Technologies, Santa Clara, CA, USA) according to manufacturer’s instruction and protocols by IntegraGen (Evry, France). Paired-end 75 bases sequencing was performed on a HiSeq2000 or HiSeq4000 instrument (Illumina, San Diego, CA, USA). Image analysis and base calling were performed using the Real Time Analysis (RTA) pipeline v. 1.14 (Illumina) with default parameters. The alignment of paired-end reads to the reference human genome (UCSC GRCh37/hg19 or UCSC GRCh38), variant calling and generation of Quality variants scores were carried out using the CASAVA v.1.8 pipeline (Illumina).
Project description:Clinical exome sequencing of cells freshly isolated from 12 human colorectal carcinoma patients (tumor endothelial cells, normal colon endothelial cells, PBMCs, each n=12) in comparison to DNA isolated from microdissected tumor cells (n=11) from corresponding FFPE-tissue blocks
Project description:Illumina human Omni5Exome arrays were used to investigate CNVs in SÑzary syndrome tumours as part of a larger study involving whole exome sequencing of the same samples and targeted resequencing of a further cohort. 16 Samples underwent SNP array including 10 tumour/gDNA matched samples that also underwent whole exome sequencing, public databases were used as further control data for calling CNVs.
Project description:Dataset consists of forty vcf files, outcome of variant calling with caveman algorithm of matched bam file (TUMOR and NORMAL) of RRMM patients. Bam files were obtained from whole exome sequencing!
