SEQanswers

Go Back   SEQanswers > Sequencing Technologies/Companies > Illumina/Solexa



Similar Threads
Thread Thread Starter Forum Replies Last Post
Problem with quality of TILE barthez95 Illumina/Solexa 0 05-30-2018 12:31 PM
Per tile sequence quality - when to go back to the sequencers? mlewis Illumina/Solexa 9 07-11-2017 09:16 PM
Poor per tile sequence quality cd1 Illumina/Solexa 4 06-27-2017 01:08 PM
Reason for POOR per tile sequence quality Justin87 Illumina/Solexa 2 03-14-2017 05:37 AM
Quality per tile starbug Illumina/Solexa 0 09-20-2016 12:17 PM

Reply
 
Thread Tools
Old 03-02-2019, 09:14 AM   #1
djh1002@cam.ac.uk
Junior Member
 
Location: Cambridge

Join Date: May 2015
Posts: 1
Default Poor per tile quality on top surface

Dear All,
We've been sequencing CRISPR guide RNA libraries for a while and had several high quality libraries sequenced on HiSeq4000. However the latest one shows this QC fail with very poor sequence across almost all of the top surface tiles. We repeated the sequencing on another flow cell and saw exactly the same result.

We add a custom sequencing primer, but have used the exact same library construction and sequencing protocol multiple times before.

I would be extremely grateful if anyone has any helpful suggestions what could be causing this?

Picture attached.

Screenshot 2019-03-02 at 18.06.44 copy.jpg
djh1002@cam.ac.uk is offline   Reply With Quote
Old 03-03-2019, 04:54 AM   #2
GenoMax
Senior Member
 
Location: East Coast USA

Join Date: Feb 2008
Posts: 6,953
Default

Have you consulted Illumina tech support? You are not doing something totally custom that is unsupported by Illumina?
GenoMax is offline   Reply With Quote
Old 03-04-2019, 05:44 PM   #3
misterc
Member
 
Location: Livermore, CA

Join Date: Jan 2016
Posts: 42
Default

You likely lost focus of the top surface. Check the FWHM on top vs. bottom surface for the run. I know some have had intermittent issues with losing focus on this platform when there's a read (even prior) that has zero base diversity. HiSeq 4000 doesn't always recover from this.
misterc is offline   Reply With Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off




All times are GMT -8. The time now is 11:03 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Single Sign On provided by vBSSO