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Abstract
The extremely high error rates reported by Keegan et al. in ‘A platform-independent method for detecting errors in metagenomic sequencing data: DRISEE’ (PLoS Comput Biol 2012;8:e1002541) for many next-generation sequencing datasets prompted us to re-examine their results. Our analysis reveals that the presence of conserved artificial sequences, e.g. Illumina adapters, and other naturally occurring sequence motifs accounts for most of the reported errors. We conclude that DRISEE reports inflated levels of sequencing error, particularly for Illumina data. Tools offered for evaluating large datasets need scrupulous review before they are implemented.
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Hafner M, Renwick N, Brown M, Mihailović A, Holoch D, Lin C, Pena JT, Nusbaum JD, Morozov P, Ludwig J, Ojo T, Luo S, Schroth G, Tuschl T. RNA-ligase-dependent biases in miRNA representation in deep-sequenced small RNA cDNA libraries. RNA 2011; 17:1697-712. [PMID: 21775473 PMCID: PMC3162335 DOI: 10.1261/rna.2799511] [Citation(s) in RCA: 256] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Sequencing of small RNA cDNA libraries is an important tool for the discovery of new RNAs and the analysis of their mutational status as well as expression changes across samples. It requires multiple enzyme-catalyzed steps, including sequential oligonucleotide adapter ligations to the 3' and 5' ends of the small RNAs, reverse transcription (RT), and PCR. We assessed biases in representation of miRNAs relative to their input concentration, using a pool of 770 synthetic miRNAs and 45 calibrator oligoribonucleotides, and tested the influence of Rnl1 and two variants of Rnl2, Rnl2(1-249) and Rnl2(1-249)K227Q, for 3'-adapter ligation. The use of the Rnl2 variants for adapter ligations yielded substantially fewer side products compared with Rnl1; however, the benefits of using Rnl2 remained largely obscured by additional biases in the 5'-adapter ligation step; RT and PCR steps did not have a significant impact on read frequencies. Intramolecular secondary structures of miRNA and/or miRNA/3'-adapter products contributed to these biases, which were highly reproducible under defined experimental conditions. We used the synthetic miRNA cocktail to derive correction factors for approximation of the absolute levels of individual miRNAs in biological samples. Finally, we evaluated the influence of 5'-terminal 5-nt barcode extensions for a set of 20 barcoded 3' adapters and observed similar biases in miRNA read distribution, thereby enabling cost-saving multiplex analysis for large-scale miRNA profiling.
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Affiliation(s)
- Markus Hafner
- Howard Hughes Medical Institute, Laboratory for RNA Molecular Biology, The Rockefeller University, New York, New York 10065, USA
| | - Neil Renwick
- Howard Hughes Medical Institute, Laboratory for RNA Molecular Biology, The Rockefeller University, New York, New York 10065, USA
| | - Miguel Brown
- Howard Hughes Medical Institute, Laboratory for RNA Molecular Biology, The Rockefeller University, New York, New York 10065, USA
| | - Aleksandra Mihailović
- Howard Hughes Medical Institute, Laboratory for RNA Molecular Biology, The Rockefeller University, New York, New York 10065, USA
| | - Daniel Holoch
- Howard Hughes Medical Institute, Laboratory for RNA Molecular Biology, The Rockefeller University, New York, New York 10065, USA
| | - Carolina Lin
- Howard Hughes Medical Institute, Laboratory for RNA Molecular Biology, The Rockefeller University, New York, New York 10065, USA
| | - John T.G. Pena
- Howard Hughes Medical Institute, Laboratory for RNA Molecular Biology, The Rockefeller University, New York, New York 10065, USA
- Weill Cornell Medical College, Dyson Vision Research Institute, New York, New York 10065, USA
| | - Jeffrey D. Nusbaum
- Howard Hughes Medical Institute, Laboratory for RNA Molecular Biology, The Rockefeller University, New York, New York 10065, USA
| | - Pavel Morozov
- Howard Hughes Medical Institute, Laboratory for RNA Molecular Biology, The Rockefeller University, New York, New York 10065, USA
| | - Janos Ludwig
- Howard Hughes Medical Institute, Laboratory for RNA Molecular Biology, The Rockefeller University, New York, New York 10065, USA
| | - Tolulope Ojo
- Howard Hughes Medical Institute, Laboratory for RNA Molecular Biology, The Rockefeller University, New York, New York 10065, USA
| | - Shujun Luo
- Illumina, Inc., Hayward, California 94545, USA
| | | | - Thomas Tuschl
- Howard Hughes Medical Institute, Laboratory for RNA Molecular Biology, The Rockefeller University, New York, New York 10065, USA
- Corresponding author.E-mail .
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