Hi, apologies for this basic question as I am new to the field. I have been checking my NGS data using FastQC and the checks fail on the Kmer content section. There appears to be a sequence TAGATCGGAA at position 90-100 bp in the reads which is enriched around 12 fold (Obs/Exp Max). However nothing shows up in the 'Overrepresented sequences' or 'Adapter content' sections of the report (complete flat line). The sequencing was done as BGI and I do not know what primers were used. My question is should I be trying to remove this Kmer sequence?

<img alt="screenshot" src="http://i483.photobucket.com/albums/rr194/Kez_Cleal/Screen%20Shot%202015-05-28%20at%2013.11.25_zpsagvhw2h3.png" style="height:50%; width:50%" />

If I use grep on the first million reads in my fastq file to look for the sequence I only find 36 which appears to be quite a low number?

    $ gunzip -c data1.fq.gz | head -4000000 | grep TAGATCGGAA | wc -l

Thanks for the help
No, there's no point in removing that. It's likely that that's just a bit of adapter contamination (I think the adapter contamination section of FastQC is looking for closer to full-length adapters, rather than just 5-8 bases). Go ahead and trim adapters regardless.