kmer content failling with fastqc
1
0
Entering edit mode
6.5 years ago

Dear all I have trimmed my data(illumina 2*150PE) using bbduk from bbmap suite and still have this issue with fastqc (see photos) as failling kmer content, do you have any suggestion to deal with this problem befor downstream analysis? thank you very much. kmercontent enter image description here

trimming bbduk adaptor trimming NGS Illumina • 3.1k views
ADD COMMENT
2
Entering edit mode

I suggest that you not worry about the kmer content failing and move forward with the analysis. This has been one of the tests that is now turned off by default in new FastQC since it causes new people to worry for not always valid reasons.

ADD REPLY
0
Entering edit mode

Indeed. I have never once seen any sample that has passed all of these FASTQC parameters.

ADD REPLY
1
Entering edit mode

In my experience kmer content often seems to fail, and I've never figured out why. Nor has it ever seemed to really matter for downstream assembly etc.

ADD REPLY
0
Entering edit mode

You did not link a picture, and might read this first.

ADD REPLY
0
Entering edit mode

Please follow these steps to upload pictures How to add images to a Biostars post

ADD REPLY
0
Entering edit mode

kmer summary_PNG

ADD REPLY
0
Entering edit mode

did you compare them against the index sequences?

ADD REPLY
0
Entering edit mode

No, how can I proceed ?

ADD REPLY
0
Entering edit mode

Whilst 5' seems trimmed it looks like 3' is not. Did you trimmed both ends ?

ADD REPLY
0
Entering edit mode

thank you all for your answer.

ADD REPLY
0
Entering edit mode

If you already trimmed both ends you may have to start the trimming over again changing your adapter sequence file. Find your entire repeated sequence in your original reads then do the trimming again with the modified file.

ADD REPLY

Login before adding your answer.

Traffic: 2148 users visited in the last hour
Help About
FAQ
Access RSS
API
Stats

Use of this site constitutes acceptance of our User Agreement and Privacy Policy.

Powered by the version 2.3.6