scholarly journals UNCROSS2: identification of cross-talk in 16S rRNA OTU tables

2018 ◽  
Author(s):  
Robert C. Edgar
Keyword(s):  
Ribosomal Rna ◽  
Cross Talk ◽  
Biological Diversity ◽  
Amplicon Sequencing ◽  
Next Generation ◽  
Mock Community ◽  
Repertoire Analysis ◽  
Microbial Metagenomics ◽  
Tumor Sequencing ◽  
Generation Sequencing

AbstractNext-generation amplicon sequencing is widely used for surveying biological diversity in applications such as microbial metagenomics, immune system repertoire analysis and targeted tumor sequencing of cancer-associated genes. In such studies, assignment of reads to incorrect samples (cross-talk) is a well-documented problem that is rarely considered in practice. Here, I describe UNCROSS2, an algorithm designed to detect and filter cross-talk in OTU tables generated by next-generation sequencing of the 16S ribosomal RNA gene. On eight published datasets, cross-talk rates are estimated to range from 0.4% to 1.5% mis-assigned reads. On a mock community test, UNCROSS2 identifies spurious counts due to cross-talk with sensitivity ∼80% to 90% and error rate from ∼1% to ∼20%, but it is not clear whether the accuracy of the algorithm is sufficient to decisively improve diversity rates in practice.

scholarly journals UNCROSS: Filtering of high-frequency cross-talk in 16S amplicon reads

2016 ◽  
Author(s):  
Robert C. Edgar
Keyword(s):  
Ribosomal Rna ◽  
Cross Talk ◽  
High Frequency ◽  
Biological Diversity ◽  
Illumina Miseq ◽  
Amplicon Sequencing ◽  
Illumina Gaiix ◽  
Microbial Metagenomics ◽  
Tumor Sequencing ◽  
Rna I

AbstractNext-generation amplicon sequencing is widely used for surveying biological diversity in applications such as microbial metagenomics, immune system repertoire analysis and targeted tumor sequencing of cancer-associated genes. In such studies, assignment of reads to incorrect samples (cross-talk) is a well-documented problem that is rarely considered in practice. By considering unexpected OTUs in artificial (mock) samples, I estimate that cross-talk occurred for ~2% of the reads in one Illumina GAIIx run and eleven Illumina MiSeq runs targeting 16S ribosomal RNA. I also describe UNCROSS, an algorithm for detecting and filtering cross-talk in OTU tables.

scholarly journals Complexities of Next-Generation Sequencing in Solid Tumors: Case Studies

2020 ◽  
Vol 18 (9) ◽  
pp. 1150-1155
Author(s):  
Alexandra O. Sokolova ◽  
Brian H. Shirts ◽  
Eric Q. Konnick ◽  
Ginger J. Tsai ◽  
Bernardo H.L. Goulart ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Case Studies ◽  
Checkpoint Inhibitors ◽  
Hereditary Cancer Syndrome ◽  
Next Generation ◽  
Cancer Syndrome ◽  
Expert Review ◽  
Tumor Boards ◽  
Tumor Sequencing ◽  
Generation Sequencing

With the promise and potential of clinical next-generation sequencing for tumor and germline testing to impact treatment and outcomes of patients with cancer, there are also risks of oversimplification, misinterpretation, and missed opportunities. These issues risk limiting clinical benefit and, at worst, perpetuating false conclusions that could lead to inappropriate treatment selection, avoidable toxicity, and harm to patients. This report presents 5 case studies illustrating challenges and opportunities in clinical next-generation sequencing interpretation and clinical application in solid tumor oncologic care. First is a case that dissects the origin of an ATM mutation as originating from a hematopoietic clone rather than the tumor. Second is a case illustrating the potential for tumor sequencing to suggest germline variants associated with a hereditary cancer syndrome. Third are 2 cases showing the potential for variant reclassification of a germline variant of uncertain significance when considered alongside family history and tumor sequencing results. Finally, we describe a case illustrating challenges with using microsatellite instability for predicting tumor response to immune checkpoint inhibitors. The common theme of the case studies is the importance of examining clinical context alongside expert review and interpretation, which together highlight an expanding role for contextual examination and multidisciplinary expert review through molecular tumor boards.

scholarly journals Pisces: An Accurate and Versatile Variant Caller for Somatic and Germline Next-Generation Sequencing Data

2018 ◽  
Author(s):  
Tamsen Dunn ◽  
Gwenn Berry ◽  
Dorothea Emig-Agius ◽  
Yu Jiang ◽  
Serena Lei ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Gene Mutations ◽  
Variant Calling ◽  
Amplicon Sequencing ◽  
Supplementary Information ◽  
Next Generation Sequencing Data ◽  
Next Generation ◽  
Sequencing Data ◽  
Ras Gene ◽  
Generation Sequencing

AbstractMotivationNext-Generation Sequencing (NGS) technology is transitioning quickly from research labs to clinical settings. The diagnosis and treatment selection for many acquired and autosomal conditions necessitate a method for accurately detecting somatic and germline variants, suitable for the clinic.ResultsWe have developed Pisces, a rapid, versatile and accurate small variant calling suite designed for somatic and germline amplicon sequencing applications. Pisces accuracy is achieved by four distinct modules, the Pisces Read Stitcher, Pisces Variant Caller, the Pisces Variant Quality Recalibrator, and the Pisces Variant Phaser. Each module incorporates a number of novel algorithmic strategies aimed at reducing noise or increasing the likelihood of detecting a true variant.AvailabilityPisces is distributed under an open source license and can be downloaded from https://github.com/Illumina/Pisces. Pisces is available on the BaseSpace™ SequenceHub as part of the TruSeq Amplicon workflow and the Illumina Ampliseq Workflow. Pisces is distributed on Illumina sequencing platforms such as the MiSeq™, and is included in the Praxis™ Extended RAS Panel test which was recently approved by the FDA for the detection of multiple RAS gene [email protected] informationSupplementary data are available online.

scholarly journals Accuracy of microbial community diversity estimated by closed- and open-reference OTUs

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3889 ◽  
Author(s):  
Robert C. Edgar
Keyword(s):  
Ribosomal Rna ◽  
De Novo ◽  
Community Diversity ◽  
Reference Database ◽  
Mock Community ◽  
Variable Regions ◽  
Operational Taxonomic Units ◽  
Sequencing Technologies ◽  
Generation Sequencing ◽  
Mock Communities

Next-generation sequencing of 16S ribosomal RNA is widely used to survey microbial communities. Sequences are typically assigned to Operational Taxonomic Units (OTUs). Closed- and open-reference OTU assignment matches reads to a reference database at 97% identity (closed), then clusters unmatched reads using a de novo method (open). Implementations of these methods in the QIIME package were tested on several mock community datasets with 20 strains using different sequencing technologies and primers. Richness (number of reported OTUs) was often greatly exaggerated, with hundreds or thousands of OTUs generated on Illumina datasets. Between-sample diversity was also found to be highly exaggerated in many cases, with weighted Jaccard distances between identical mock samples often close to one, indicating very low similarity. Non-overlapping hyper-variable regions in 70% of species were assigned to different OTUs. On mock communities with Illumina V4 reads, 56% to 88% of predicted genus names were false positives. Biological inferences obtained using these methods are therefore not reliable.

scholarly journals Nanoliter-scale next-generation sequencing library-mediated high-throughput 16S rRNA microbial community profiling

BioTechniques ◽  
2020 ◽  
Vol 68 (4) ◽  
pp. 204-210
Author(s):  
Hui Zhang ◽  
Xiangdan Yu ◽  
Zhe Zhang ◽  
Zhenhua Liu ◽  
Cong Tang ◽  
...  
Keyword(s):  
Microbial Community ◽  
Next Generation Sequencing ◽  
Large Scale ◽  
Amplicon Sequencing ◽  
Next Generation ◽  
Library Construction ◽  
Microbial Community Profiling ◽  
Community Profiling ◽  
Sequencing Library ◽  
Generation Sequencing

An ultra-high-throughput workflow for next-generation sequencing library construction at nanoliter scale for amplicon sequencing, termed Smartchip Nanowell Platform for Target Enrichment, was established using a nanodispenser system and a nanoliter-scale PCR chip. To demonstrate its cost and time advantages over conventional methods for library construction, quality control and pooling for large-scale samples, target amplicon sequencing of the 16S ribosomal RNA gene V3-V4 region widely used for microbial community profiling was chosen for comparison. The finding of no significant difference in microbial community profiling between the two methods strongly supports the conclusion that Smartchip Nanowell Platform for Target Enrichment is a cost-effective method for next-generation sequencing library construction for large-scale samples to conduct amplicon sequencing-based applications.

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