Title
GeneScissors: a comprehensive approach to detecting and correcting spurious transcriptome inference owing to RNA-seq reads misalignment.
Abstract
Motivation: RNA-seq techniques provide an unparalleled means for exploring a transcriptome with deep coverage and base pair level resolution. Various analysis tools have been developed to align and assemble RNA-seq data, such as the widely used TopHat/Cufflinks pipeline. A common observation is that a sizable fraction of the fragments/reads align to multiple locations of the genome. These multiple alignments pose substantial challenges to existing RNA-seq analysis tools. Inappropriate treatment may result in reporting spurious expressed genes (false positives) and missing the real expressed genes (false negatives). Such errors impact the subsequent analysis, such as differential expression analysis. In our study, we observe that similar to 3.5% of transcripts reported by TopHat/Cufflinks pipeline correspond to annotated nonfunctional pseudogenes. Moreover, similar to 10.0% of reported transcripts are not annotated in the Ensembl database. These genes could be either novel expressed genes or false discoveries. Results: We examine the underlying genomic features that lead to multiple alignments and investigate how they generate systematic errors in RNA-seq analysis. We develop a general tool, GeneScissors, which exploits machine learning techniques guided by biological knowledge to detect and correct spurious transcriptome inference by existing RNA-seq analysis methods. In our simulated study, GeneScissors can predict spurious transcriptome calls owing to misalignment with an accuracy close to 90%. It provides substantial improvement over the widely used TopHat/Cufflinks or MapSplice/Cufflinks pipelines in both precision and F-measurement. On real data, GeneScissors reports 53.6% less pseudogenes and 0.97% more expressed and annotated transcripts, when compared with the TopHat/Cufflinks pipeline. In addition, among the 10.0% unannotated transcripts reported by TopHat/Cufflinks, GeneScissors finds that > 16.3% of them are false positives.
Year
DOI
Venue
2013
10.1093/bioinformatics/btt216
BIOINFORMATICS
Keywords
Field
DocType
sequence alignment,artificial intelligence,pseudogenes,gene expression profiling,genomics
Pseudogene,Genome,Data mining,RNA-Seq,Ensembl,Computer science,Genomics,TopHat,Bioinformatics,Spurious relationship,False positive paradox
Journal
Volume
Issue
ISSN
29
13
1367-4803
Citations 
PageRank 
References 
3
0.50
3
Authors
7
Name
Order
Citations
PageRank
Zhaojun Zhang1996.62
Shunping Huang2676.17
Jack Wang3153.10
Xiang Zhang4101.73
Fernando Pardo-Manuel de Villena5498.21
Leonard McMillan63685323.97
Wei Wang77122746.33