GSNAP error: Paired-end accessions do not match
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3 months ago
Joshua ▴ 10

Hi,

This is my first time using GSNAP aligner. When I tried to align paired end fastq file (which contains only mitochondrial sequence) using GSNAP, I got the following error. Could anyone please guide me how I can resolve this issue.

Here are the specific reads that are causing this error.

@SRR6435655.2790253
TCTAGACCCTACCCCCAACTCCCTCCCATTAATTAGCCTTCTCTTAGCAGCAGCAGGAAAGTCAGCTCAATTCGGCCTCCATCCCTGACTCCCATCTGCCATAGAAGGCCCAGCCCCAGTCTCAGCCCTACTCCACTCCAGCACTATAGTT
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BAA@CCB@@BB9@@@@BBBBC?@BC@@BBABBBABCB@BACBCB@BCBBCBBCBBCABCBC@CBCBCDBCCBD@AC@CCACCDAACDCCCDAACCDCDCABCCDCCDACAAC=CAAABDBCDDCDCAACCCDDACCCCACDCCCCBAAB@A


@SRR6435655.1510133
TTACTCTGCAGCCTTTCCAGGGTTTGCTGAAGATGGAGGTATTTAGGCTGGGCAAGAGGTGGTGAGGTAAATTGGGGTTTATCGATTATAGAACAGGTTCCTTTAGAGGGATATAAAGCACCGCCAAGTCCTTTGAGTTTTAAGCTGTTGC
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NGS GMAP alignment GSNAP aligner • 563 views
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Hi!do you have the same number of reads and sorted in the same order in both files?

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Thank you iraun for your guidance. I haven't sorted my fastq files before, I think that's why I got this error. After sorting the fastq file and keeping only the paired reads, I was able to resolve it.

However, I'm getting the following error now.

I think it's because my reference genome has not been indexed correctly. Previously, I downloaded the indexed genome from this website (http://research-pub.gene.com/gmap/) (UCSC hg19/GRCh37)

Then I tried to index my reference genome using gmap_build, but I got the following error. Please guide me how I can resolve this issue.

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Glad that you manage to advance a bit at least. Regarding the new error.. I am not sure, can you try to specify -d chrM?

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Thank you iraun for your guidance. I'm able to index the reference genome correctly, also I'm able to align my reads with reference genome.