Project description:A technical comparison of Agilent SureSelect Focussed Exome and TruSight One Mendeliome sequencing kits, by triplicate sequencing of the cell line DNA of NA12878, NA12891, NA12892 and NIST RM8395
Project description:Targeted enrichment-based next-generation sequencing or whole exome sequencing were taken for patients with hypomyelinating leukodystrophies to reveal genetic aetiologies. All genomic DNA used in the experiments was extracted from the peripheral leukocytes. A complete kit was synthetized using the Agilent SureSelect Target Enrichment technique, capturing the coding regions from 104 candidate genes, including their exons and exon-intron boundaries (11,473 probes, 383.065 kbp in total). The following NGS which included equipment and reagents was performed on an Illumina NEXTSEQ500 platform manufactured by Illumina (San Diego, California, USA) using paired-end sequencing of 110 bp. The clean paired-end reads were aligned to the human reference genome build hg19, which was previously annotated using ANNOVAR, in addition to insertion-deletion (indel) and single-nucleotide polymorphism (SNP) calling.
Project description:Targeted enrichment-based next-generation sequencing or whole exome sequencing were taken for patients with hypomyelinating leukodystrophies to reveal genetic aetiologies. All genomic DNA used in the experiments was extracted from the peripheral leukocytes. A complete kit was synthetized using the Agilent SureSelect Target Enrichment technique, capturing the coding regions from 104 candidate genes, including their exons and exon-intron boundaries (11,473 probes, 383.065 kbp in total). The following NGS which included equipment and reagents was performed on an Illumina NEXTSEQ500 platform manufactured by Illumina (San Diego, California, USA) using paired-end sequencing of 110 bp. The clean paired-end reads were aligned to the human reference genome build hg19, which was previously annotated using ANNOVAR, in addition to insertion-deletion (indel) and single-nucleotide polymorphism (SNP) calling.
Project description:Accurate and comprehensive genomic annotation, including the full list of protein-coding genes, is vital for understanding the molecular mechanisms of human biology. We have previously shown that the genome contains a multitude of yet hidden functional exons and transcripts, some of which might represent novel mRNAs. These results resonate with those from other groups and strongly argue that two decades after the completion of the first draft of the human genome sequence, the current annotation of human genes and transcripts remains far from being complete. Using a targeted RNA enrichment technique, we showed that one of the novel functional exons previously discovered by us and currently annotated as part of a long non-coding RNA, is actually a part of a novel protein-coding gene, InSETG-4, which encodes a novel human protein with no known homologs or motifs. We found that InSETG-4 is induced by various DNA-damaging agents across multiple cell types and therefore might represent a novel component of DNA damage response. Despite its low abundance in bulk cell populations, InSETG-4 exhibited expression restricted to a small fraction of cells, as demonstrated by the amplification-based single-molecule fluorescence in situ hybridization (asmFISH) analysis. This study argues that yet undiscovered human protein-coding genes exist and provides an example of how targeted RNA enrichment techniques can help to fill this major gap in our knowledge of the information encoded in the human genome.
Project description:Norovirus full-genome sequencing is challenging due to sequence heterogeneity among genomes. Previous methods have relied on PCR amplification, which is problematic due to primer design, and transcriptome sequencing (RNA-Seq), which nonspecifically sequences all RNA, including host and bacterial RNA, in stool specimens. Target enrichment uses a panel of custom-designed 120-mer RNA baits that are complementary to all publicly available norovirus sequences, with multiple baits targeting each position of the genome, which overcomes the challenge of primer design. Norovirus genomes are enriched from stool RNA extracts to minimize the sequencing of nontarget RNA. SureSelect target enrichment and Illumina sequencing were used to sequence full genomes from 507 norovirus-positive stool samples with reverse transcription-real-time PCR cycle threshold (CT) values of 10 to 43. Sequencing on an Illumina MiSeq system in batches of 48 generated, on average, 81% on-target reads per sample and 100% genome coverage with >12,000-fold read depth. Samples included genotypes GI.1, GI.2, GI.3, GI.6, GI.7, GII.1, GII.2, GII.3, GII.4, GII.5, GII.6, GII.7, GII.13, GII.14, and GII.17. When outliers were accounted for, we generated >80% genome coverage for all positive samples, regardless of CT values. A total of 164 samples were tested in parallel with conventional PCR genotyping of the capsid shell domain; 164/164 samples were successfully sequenced, compared to 158/164 samples that were amplified by PCR. Four of the samples that failed capsid PCR analysis had low titers, which suggests that target enrichment is more sensitive than gel-based PCR. Two samples failed PCR due to primer mismatches; target enrichment uses multiple baits targeting each position, thus accommodating sequence heterogeneity among norovirus genomes.
Project description:Obtaining reliable and high fidelity next-generation sequencing (NGS) data requires to choose a suitable sequencing platform and a library preparation approach, which both have their inherent assay-specific limitations. Here, we present the results of successful adaptation of SureSelect hybridisation-based target enrichment protocol for the sequencing on the Ion Torrent S5 platform, which is designed to work preferably with amplicon-based panels. In our study, we applied a custom NGS panel to screen a cohort of 16 unrelated patients affected by premature fusion of the cranial sutures, i.e. craniosynostosis (CS). CS occurs either as an isolated malformation or in a syndromic form, representing a genetically heterogeneous and clinically variable group of disorders. The approach presented here allowed us to achieve high quality NGS data and confirmed molecular diagnosis in 19% of cases, reaching the diagnostic yield similar to some of the published research reports. In conclusion, we demonstrated that an alternative enrichment strategy for library preparations can be successfully applied prior to sequencing on the Ion Torrent S5 platform. Also, we proved that the custom NGS panel designed by us represents a useful and effective tool in the molecular diagnostics of patients with CS.
Project description:BackgroundPersonalised medicine is nowadays a major objective in oncology. Molecular characterization of tumours through NGS offers the possibility to find possible therapeutic targets in a time- and cost-effective way. However, the low quality and complexity of FFPE DNA samples bring a series of disadvantages for massive parallel sequencing techniques compared to high-quality DNA samples (from blood cells, cell cultures, etc.).ResultsWe performed several experiments to understand the behaviour of FFPE DNA samples during the construction of SureSelectQXT libraries. First, we designed a quality checkpoint for FFPE DNA samples based on the quantification of their amplification capability (qcPCR). We observed that FFPE DNA samples can be classified according to DIN value and qcPCR concentration into unusable, or low-quality (LQ) and good-quality (GQ) DNA. For GQ samples, we increased the amount of input DNA to 150 ng and the digestion time to 30 min, whereas for LQ samples, we used 50 ng of DNA as input but we decreased the digestion time to 1 min. In all cases, we increased the cycles of the pre-hyb PCR to 10 but decreased the cycles of the post-hyb PCR to 8. In addition, we confirmed that using half of the volume of reagents can be beneficial. Finally, in order to obtain better results, we designed a decision flow-chart to achieve a seeding concentration of 12-14 pM for MiSeq Reagent Kit v2.ConclusionsOur experiments allowed us to unveil the behaviour of low-quality FFPE DNA samples during the construction of SureSelectQXT libraries. Sequencing results showed that, using our modified SureSelectQXT protocol, the final percentage of usable reads for low-quality samples was increased more than three times allowing to reach median depth/million reads values of 76.35. This value is equivalent to ~ 0.9 and ~ 0.7 of the values obtained for good-quality FFPE and high-quality DNA respectively.