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Tuesday, March 18, 2014

qseq to fastq conversion

I was looking at some old ChIP-seq data with raw file in qseq format. I want to convert them to fastq file for mapping with bowtie.

A quick google I found:
http://www.biostars.org/p/6682/

the qseqtofastq C++ program http://www.dna.bio.keio.ac.jp/~krisp/qseq2fastq/ has to be compiled by scons, and I encountered some compiling problem. I gave it up and used this java program http://sourceforge.net/projects/snpeff/files/qseq2fastq.jar/download

Usage:

zcat myfile.qseq.tgz | java -jar qseqtofastq.jar -phred64 > myfile.fastq

it took me around 1 hour to finish the conversion of a 600MB tgz file on the computing cluster (single cpu 4GB ram).

I did have a problem at the end:

Exception in thread "main" java.lang.RuntimeException: java.lang.ArrayIndexOutOfBoundsException: 8
        at ca.mcgill.mcb.pcingola.Qseq2Fastq.main(Qseq2Fastq.java:51)
Caused by: java.lang.ArrayIndexOutOfBoundsException: 8
        at ca.mcgill.mcb.pcingola.Qseq2Fastq.main(Qseq2Fastq.java:43)


I counted the lines of the fastq file (divided by 4) and the original qseq file  , and they are equal.  So, I went ahead and mapped the fastq file with bowtie.



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