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How To Interpret Crossbow Data

Hello,

May I know how to interpret Crossbow output. Is there any chance of building a SAM or BAM file from Crossbow output. I am looking into genome mapping. I know there are many tools available for genome mapping on hadoop cluster. But I like the Crossbow interface, very easy to use.

PS: I dont have a background in Bioinformatics. I am an IT student working on Hadoop infrastructure to assess its performance for an organization.

Thanks

genome mapping paired-end

2 answers

The primary output of crossbow is a file giving evidence for SNPs (the format is described in the Crossbow manual, which is simply that of SOAPsnp). I believe that the alignment files are deleted by default, but you should be able to have them kept with either the --keep-intermediates or --keep-all flags (make sure to specify an appropriate output path).

Have you used crossbow before? May I know what are the intermediate files generated while running crossbow? Just read from Crossbow FAQ that SAM/BAM files are not generated as intermediate files. Do you know if there is any chance of building SAM/BAM files from Crossbow output or intermediate files?

No, but my understanding from elsewhere is that while the alignments aren't saved normally, they're intermediate files that can still be saved with --keep-all. That makes sense given that SOAPsnp needs something as input.

yea definitely the intermediate files can be saved using those flags. But according to Crossbow manual those intermediate files are not in SAM or BAM format. And i tried looking for the intermediate files on the internet, I cant get hold of any info about it.

@bashwin.u hi ashwim, im in a similar situation. Can u please tell me how did u store the bam files on hadoop cluster so that the data will be processed by chromosome level

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