Hi Bomba

I cant know for sure without seeing your files but I originally had the same problem and it ended up being because the way the genome was named in the fasta genome file was not the same as the way it was named in column 1 of my gtf file. I would check that first.  Also- with bacteria you dont want to run cufflinks with default parameters- use the galaxy browser to check how your data looks after tophat and you will most likely see very strange gene-spanning introns. Change the max intron size to 1000-1500 and the min distnace to 101-5nt and you should get results that make much more sense.

Good luck

Noa

Dear Noa,

Can you please  tell me the parameters that I should keep while mapping bacterial transcripts using cuffkins. I have kept the default parameters as in Cufflinks and used my custom genome annotation  in gff3 format. The cufflinks seems to work Ok but all the FPKM values in these files are zero. As suggested by other users I have checked the correctness of my GFF3 files. The corresponding fasta file was used for mapping the transcripts using Bowtie. Are there any special trick for mapping bacterial transcriptome.

regards,

Bomba