RNA-seq / Differential expression using Cuffdiff

Description

This tool performs differential expression analysis using the Cufflinks package version 2.0.2.

Parameters

Details

Given GTF and BAM files, Cuffdiff performs differential expression analysis of genes and transcripts using the Cufflinks algorithm. It is currently not possible to use replicate samples in Chipster, so you have to merge all samples belonging to the same experiment group into a single BAM file.

Cufflinks can detect sequence-specific bias and correct for it in abundance estimation. Note that bias correction works only if your data was produced with a strand specific protocol.

By default, Cufflinks will uniformly divide each multi-mapped read to all of the positions it maps to. If multi-mapped read correction is enabled, Cufflinks will re-estimate the transcript abundances dividing each multi-mapped read probabilistically based on the initial abundance estimation, the inferred fragment length and fragment bias, if bias correction is enabled.

FDR-adjusted p-values (q-values) are calculated. The concise output files include only those genes or transcripts which have a q-value lower than the given FDR. The value of the Significant-column is adjusted accordingly (yes/no) in all output files.

Output

The concise analysis output consists of the following files:

If the complete output is selected, the following optional outputs may also be generated:

1. FPKM tracking files

2. Count tracking files

3. Read group tracking files

4. Differential expression tests

5. Differential splicing tests

6. Differential coding output

7. Differential promoter use

8. Read group info

8. Run info

References

This tool uses the Cufflinks package for statistical analysis. Please read the following article for more detailed information:

Trapnell C, Williams BA, Pertea G, Mortazavi A, Kwan G, van Baren MJ, Salzberg SL, Wold BJ, Pachter L. Transcript assembly and quantification by RNA-Seq reveals unannotated transcripts and isoform switching during cell differentiation. Nat Biotechnol. 2010 May;28(5):511-5.