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Manuel Nelson

What can cause poly-G tails on NextSeq fastq from seemingly failed...

Dave Obrien  Follow
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Dallas Hall's Space  Follow

Thank you both!

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Asad Hussain  Follow

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Ashwin Adhikari  Follow

NextSeq / NovaSeq uses two-colour chemistry, which means 4 bases (A/T/C/G) are represented by 2 colors of light. Green is T, red is C, yellow (green + red) is A, and None (no green, no red) is G. As the sequencing goes cycle by cycle, the green and red light signal strength become weaker. So more and more A/T/C will be mistakenly categorized as G in the tails of reads. And finally it results in polyG.

One open source tool can be used to trim polyG tails automatically for NextSeq / NovaSeq reads. This tool is fastp, which is available at: https://github.com/OpenGene/fastp

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