scholarly journals ReALLEN: structural variation discovery in cancer genome by sensitive analysis of single-end reads

2018 ◽  
Author(s):  
Ryo Kanno ◽  
Daisuke Tanaka ◽  
Hideaki Nanamiya ◽  
Takao Isogai

AbstractBackgroundThe structural abnormalities in chromosomes are important issues in cancer genomics. Next generation sequencing technologies have big potentials to detect the structural variations precisely and comprehensively. Nevertheless, it is still difficult problem to detect large structural variations from short read sequence data. Major efforts have been achieved with paired-end reads, since discordant pairs directly reflect the existence of large rearrangement. Furthermore, approaches to detect structural variations from single-end reads are still worthwhile challenge because they allow wide choices of sequencing platforms.ResultWe present ReALLEN, a series of tools to detect genomic rearrangement with base-pair resolution from single-end reads provided by next generation sequencing. We examined the performance of ReALLEN using simulated dataset and real dataset sequenced by Ion Torrent systems. In most cases on the simulated dataset, ReALLEN showed nearly 100% precision and better sensitivity than other major tools. Notably, ReALLEN showed stable scores even if it was on some unfavorable conditions, for example, low coverage or small variant size. On the real dataset sequenced by Ion Torrent systems, ReALLEN accurately found an insertional translocation that was crucial for the diagnosis of chronic myeloid leukemia.ConclusionReALLEN is useful to researchers in finding genomic rearrangements. It will contribute to discovery of cancer-specific fusion proteins, precise diagnosis of known types of cancers, and understanding of genetic diseases caused by abnormal chromosomes.


2020 ◽  
Vol 48 (12) ◽  
pp. 030006052096777
Author(s):  
Peisong Chen ◽  
Xuegao Yu ◽  
Hao Huang ◽  
Wentao Zeng ◽  
Xiaohong He ◽  
...  

Introduction To evaluate a next-generation sequencing (NGS) workflow in the screening and diagnosis of thalassemia. Methods In this prospective study, blood samples were obtained from people undergoing genetic screening for thalassemia at our centre in Guangzhou, China. Genomic DNA was polymerase chain reaction (PCR)-amplified and sequenced using the Ion Torrent system and results compared with traditional genetic analyses. Results Of the 359 subjects, 148 (41%) were confirmed to have thalassemia. Variant detection identified 35 different types including the most common. Identification of the mutational sites by NGS were consistent with those identified by Sanger sequencing and Gap-PCR. The sensitivity and specificities of the Ion Torrent NGS were 100%. In a separate test of 16 samples, results were consistent when repeated ten times. Conclusion Our NGS workflow based on the Ion Torrent sequencer was successful in the detection of large deletions and non-deletional defects in thalassemia with high accuracy and repeatability.





2020 ◽  
Vol 79 (2) ◽  
pp. 105-113
Author(s):  
Abdul Bari Muneera Parveen ◽  
Divya Lakshmanan ◽  
Modhumita Ghosh Dasgupta

The advent of next-generation sequencing has facilitated large-scale discovery and mapping of genomic variants for high-throughput genotyping. Several research groups working in tree species are presently employing next generation sequencing (NGS) platforms for marker discovery, since it is a cost effective and time saving strategy. However, most trees lack a chromosome level genome map and validation of variants for downstream application becomes obligatory. The cost associated with identifying potential variants from the enormous amount of sequence data is a major limitation. In the present study, high resolution melting (HRM) analysis was optimized for rapid validation of single nucleotide polymorphisms (SNPs), insertions or deletions (InDels) and simple sequence repeats (SSRs) predicted from exome sequencing of parents and hybrids of Eucalyptus tereticornis Sm. ? Eucalyptus grandis Hill ex Maiden generated from controlled hybridization. The cost per data point was less than 0.5 USD, providing great flexibility in terms of cost and sensitivity, when compared to other validation methods. The sensitivity of this technology in variant detection can be extended to other applications including Bar-HRM for species authentication and TILLING for detection of mutants.



PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6661 ◽  
Author(s):  
Arianna Nicolussi ◽  
Francesca Belardinilli ◽  
Yasaman Mahdavian ◽  
Valeria Colicchia ◽  
Sonia D’Inzeo ◽  
...  

Background Conventional methods used to identify BRCA1 and BRCA2 germline mutations in hereditary cancers, such as Sanger sequencing/multiplex ligation-dependent probe amplification (MLPA), are time-consuming and expensive, due to the large size of the genes. The recent introduction of next-generation sequencing (NGS) benchtop platforms offered a powerful alternative for mutation detection, dramatically improving the speed and the efficiency of DNA testing. Here we tested the performance of the Ion Torrent PGM platform with the Ion AmpliSeq BRCA1 and BRCA2 Panel in our clinical routine of breast/ovarian hereditary cancer syndrome assessment. Methods We first tested the NGS approach in a cohort of 11 patients (training set) who had previously undergone genetic diagnosis in our laboratory by conventional methods. Then, we applied the optimized pipeline to the consecutive cohort of 136 uncharacterized probands (validation set). Results By minimal adjustments in the analytical pipeline of Torrent Suite Software we obtained a 100% concordance with Sanger results regarding the identification of single nucleotide alterations, insertions, and deletions with the exception of three large genomic rearrangements (LGRs) contained in the training set. The optimized pipeline applied to the validation set (VS), identified pathogenic and polymorphic variants, including a novel BRCA2 pathogenic variant at exon 3, 100% of which were confirmed by Sanger in their correct zygosity status. To identify LGRs, all negative samples of the VS were subjected to MLPA analysis. Discussion Our experience strongly supports that the Ion Torrent PGM technology in BRCA1 and BRCA2 germline variant identification, combined with MLPA analysis, is highly sensitive, easy to use, faster, and cheaper than traditional (Sanger sequencing/MLPA) approaches.



2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Suguru Takeuchi ◽  
Jun-ichi Kawada ◽  
Kazuhiro Horiba ◽  
Yusuke Okuno ◽  
Toshihiko Okumura ◽  
...  

Abstract Next-generation sequencing (NGS) has been applied in the field of infectious diseases. Bronchoalveolar lavage fluid (BALF) is considered a sterile type of specimen that is suitable for detecting pathogens of respiratory infections. The aim of this study was to comprehensively identify causative pathogens using NGS in BALF samples from immunocompetent pediatric patients with respiratory failure. Ten patients hospitalized with respiratory failure were included. BALF samples obtained in the acute phase were used to prepare DNA- and RNA-sequencing libraries. The libraries were sequenced on MiSeq, and the sequence data were analyzed using metagenome analysis tools. A mean of 2,041,216 total reads were sequenced for each library. Significant bacterial or viral sequencing reads were detected in eight of the 10 patients. Furthermore, candidate pathogens were detected in three patients in whom etiologic agents were not identified by conventional methods. The complete genome of enterovirus D68 was identified in two patients, and phylogenetic analysis suggested that both strains belong to subclade B3, which is an epidemic strain that has spread worldwide in recent years. Our results suggest that NGS can be applied for comprehensive molecular diagnostics as well as surveillance of pathogens in BALF from patients with respiratory infection.



2016 ◽  
Vol 140 (10) ◽  
pp. 1085-1091 ◽  
Author(s):  
Eric J. Duncavage ◽  
Haley J. Abel ◽  
Jason D. Merker ◽  
John B. Bodner ◽  
Qin Zhao ◽  
...  

Context.—Most current proficiency testing challenges for next-generation sequencing assays are methods-based proficiency testing surveys that use DNA from characterized reference samples to test both the wet-bench and bioinformatics/dry-bench aspects of the tests. Methods-based proficiency testing surveys are limited by the number and types of mutations that either are naturally present or can be introduced into a single DNA sample. Objective.—To address these limitations by exploring a model of in silico proficiency testing in which sequence data from a single well-characterized specimen are manipulated electronically. Design.—DNA from the College of American Pathologists reference genome was enriched using the Illumina TruSeq and Life Technologies AmpliSeq panels and sequenced on the MiSeq and Ion Torrent platforms, respectively. The resulting data were mutagenized in silico and 26 variants, including single-nucleotide variants, deletions, and dinucleotide substitutions, were added at variant allele fractions (VAFs) from 10% to 50%. Participating clinical laboratories downloaded these files and analyzed them using their clinical bioinformatics pipelines. Results.—Laboratories using the AmpliSeq/Ion Torrent and/or the TruSeq/MiSeq participated in the 2 surveys. On average, laboratories identified 24.6 of 26 variants (95%) overall and 21.4 of 22 variants (97%) with VAFs greater than 15%. No false-positive calls were reported. The most frequently missed variants were single-nucleotide variants with VAFs less than 15%. Across both challenges, reported VAF concordance was excellent, with less than 1% median absolute difference between the simulated VAF and mean reported VAF. Conclusions.—The results indicate that in silico proficiency testing is a feasible approach for methods-based proficiency testing, and demonstrate that the sensitivity and specificity of current next-generation sequencing bioinformatics across clinical laboratories are high.



2010 ◽  
Vol 76 (12) ◽  
pp. 3863-3868 ◽  
Author(s):  
J. Kirk Harris ◽  
Jason W. Sahl ◽  
Todd A. Castoe ◽  
Brandie D. Wagner ◽  
David D. Pollock ◽  
...  

ABSTRACT Constructing mixtures of tagged or bar-coded DNAs for sequencing is an important requirement for the efficient use of next-generation sequencers in applications where limited sequence data are required per sample. There are many applications in which next-generation sequencing can be used effectively to sequence large mixed samples; an example is the characterization of microbial communities where ≤1,000 sequences per samples are adequate to address research questions. Thus, it is possible to examine hundreds to thousands of samples per run on massively parallel next-generation sequencers. However, the cost savings for efficient utilization of sequence capacity is realized only if the production and management costs associated with construction of multiplex pools are also scalable. One critical step in multiplex pool construction is the normalization process, whereby equimolar amounts of each amplicon are mixed. Here we compare three approaches (spectroscopy, size-restricted spectroscopy, and quantitative binding) for normalization of large, multiplex amplicon pools for performance and efficiency. We found that the quantitative binding approach was superior and represents an efficient scalable process for construction of very large, multiplex pools with hundreds and perhaps thousands of individual amplicons included. We demonstrate the increased sequence diversity identified with higher throughput. Massively parallel sequencing can dramatically accelerate microbial ecology studies by allowing appropriate replication of sequence acquisition to account for temporal and spatial variations. Further, population studies to examine genetic variation, which require even lower levels of sequencing, should be possible where thousands of individual bar-coded amplicons are examined in parallel.





Author(s):  
Noah A. Brown ◽  
Kojo S.J. Elenitoba-Johnson

Genomic testing enables clinical management to be tailored to individual cancer patients based on the molecular alterations present within cancer cells. Genomic sequencing results can be applied to detect and classify cancer, predict prognosis, and target therapies. Next-generation sequencing has revolutionized the field of cancer genomics by enabling rapid and cost-effective sequencing of large portions of the genome. With this technology, precision oncology is quickly becoming a realized paradigm for managing the treatment of cancer patients. However, many challenges must be overcome to efficiently implement the transition of next-generation sequencing from research applications to routine clinical practice, including using specimens commonly available in the clinical setting; determining how to process, store, and manage large amounts of sequencing data; determining how to interpret and prioritize molecular findings; and coordinating health professionals from multiple disciplines.



2015 ◽  
Vol 33 (15_suppl) ◽  
pp. e12521-e12521
Author(s):  
Jessica Ribeiro Gomes ◽  
Raphael Brandao Moreira ◽  
Renata D'Alpino D'Alpino ◽  
Marcelo Rocha S Cruz ◽  
Tercia Tarciane Soares de Sousa ◽  
...  


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