1
0
Entering edit mode
4.5 years ago
Sitara • 0

I used tudexo to analyze the samples of drosophila melanogaster. I used Tophat2 for alignment. There are differences in the results when used with different library normalization methods. So, I am not sure which library normalization is appropriate to use. And also will be thankful if I get to know based on which criteria cufflinks uses classic FPKM and cuffdiff uses geometric as default. Any help will be appreciated. Thanks

Cufflinks with default options --library-norm-method classic-fpkm (default) for Cufflinks --library-norm-method geometric (default) for cuffdiff

Cufflinks with other options --library-norm-method classic-fpkm (default) for Cufflinks because it doesn't support other library-norm-method --library-norm-method classic-fpkm for cuffdiff

The following are the top 10 genes:

gene                      log2_fold_change_with_default      log2_fold_change_with_other
128up                         -0.197068                       -0.0925489
14-3-3epsilon                 -0.416107                       -0.323126
14-3-3zeta                    -0.582101                       -0.43963
140up                         -0.442188                       -0.296549
18SrRNA-Psi:CR41602                   0                               0
18w                           1.04193                          1.01845
26-29-p                       0.508963                         0.623343
28SrRNA-Psi:CR40596                   0                               0
28SrRNA-Psi:CR40741                   0                               0
28SrRNA-Psi:CR41609          -0.560796                         -0.579063

RNA-Seq rna-seq sequencing assembly • 3.1k views
2
Entering edit mode

You should know that the old 'Tuxedo' pipeline of Tophat(2) and Cufflinks is no longer the "advisable" tool for RNA-seq analysis. The software is deprecated/ in low maintenance and should be replaced by HISAT2, StringTie and ballgown. See this paper: Transcript-level expression analysis of RNA-seq experiments with HISAT, StringTie and Ballgown. There are also other alternatives, including alignment with STAR and bbmap, or pseudo-alignment using salmon.

0
Entering edit mode

Thank you very much for the reply.

Couldn't agree more here. I have stopped using TopHat2 or Cufflinks for the analysis.

This is just a query, based on already analyzed data. All I want to know is, Cufflinks has classic FPKM as the normalization method CuffDiff has geometric normalization (default)

I have also tried, Cufflinks = Classic FPKM CuffDiff = Classic FPKM

And I have observed some differences between the two outputs. Would be great if you could advice me here, as to which one can I consider.

0
Entering edit mode

Please use ADD COMMENT or ADD REPLY to answer to previous reactions, as such this thread remains logically structured and easy to follow. I have now moved your reaction but as you can see it's not optimal. Adding an answer should only be used for providing a solution to the question asked.

0
Entering edit mode

6
Entering edit mode
4.5 years ago

FPKM normalization should never be used for statistics, it's known to be unreliable. The geometric normalization option (I think it ends up working similar to DESeq2 then) is preferred in all cases, though of course one shouldn't be using tophat2 or cufflinks to begin with.

0
Entering edit mode

This was clear enough for me to understand. Thanks a lot for the reply.

0
Entering edit mode