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Old 11-22-2010, 09:38 AM   #18
ngs
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Quote:
Originally Posted by adarob View Post
The multiple FPKM problem occurs when genes have transcripts that do not overlap with any other transcripts in the gene. For example, this occurs in the ENSG00000125388 gene from ENSEMBL/hg19. We are aware of this issue and will eventually change the behavior, but for now a simple solution is just to sum the FPKMs since the gene FPKMs are just the sum of the transcript FPKMs anyways. The issue should not occur in Cuffdiff.

I would not draw any conclusions about the FPKM of the FAILED genes.
Hi Adam,
I ran tophat (1.1.0) without a mouse gtf file. Run cufflinks (0.9.1) without a mouse gtf file. Then run cuffcompare with a mouse gtf file and two gtf files generated from cufflinks for my two samples. Finally, I ran cuffdiff with compare.combined.gtf and two accepted_hits.bam files.

However, I checked gene_exp.diff. I found there is still multiple FPKM problem for some genes (see below):

XLOC_000009 Cspp1 chr1:10053629-10189988 q1 q2 OK 44.5012 58.359 0.271096 -2.93789 0.00330457 yes
XLOC_000010 Arfgef1 chr1:10053629-10189988 q1 q2 OK 10.0582 7.68137 -0.269589 4.88261 1.04688e-06 yes
XLOC_000011 Arfgef1 chr1:10053629-10189988 q1 q2 OK 40.66 31.8566 -0.244 17.6406 0 yes
XLOC_000013 Arfgef1 chr1:10053629-10189988 q1 q2 OK 2.7768 40.8059 2.68753 -144.972 0 yes
XLOC_000015 Arfgef1 chr1:10053629-10189988 q1 q2 OK 54.0345 65.0081 0.18489 -12.9339 0 yes
XLOC_000016 Arfgef1 chr1:10053629-10189988 q1 q2 OK 23.4654 43.6672 0.62107 -29.4492 0 yes
XLOC_000031 Tram2 chr1:20986216-20997026 q1 q2 OK 5.8219 2.96147 -0.67594 3.70609 0.000210487 yes
XLOC_000032 Tram2 chr1:20986216-20997026 q1 q2 OK 3.33419 14.9065 1.49757 -29.7646 0 yes
XLOC_000057 Tmem131 chr1:36849038-36996484 q1 q2 OK 37.3723 30.8444 -0.191975 5.03247 4.84195e-07 yes

Did I do something wrong?

I have another question regarding gene_exp.diff file. As you can see, the first gene Cspp1 has the same coordiates (chr1:10053629-10189988) as the second gene Arfgef1. But in my mouse gtf file (from Ensembl), the coordinates for those two genes are:
Cspp1: Chromosome 1: 10,028,299-10,126,849
Arfgef1: Chromosome 1: 10,127,652-10,222,751

Those two genes are not overlapped. Why do they have the same coordinates in gene_exp.diff file?

Thank you very much!
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