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Old 02-27-2017, 07:57 AM   #103
Location: Lisbon, Portugal

Join Date: Jan 2012
Posts: 21

Just to add our 2 cents.

We have a MiSeq running since 2013, and after some hickups we're now stable with it and reasonably happy.

We just recently installed a NextSeq500 and our first tests are not great. Q30 is >80%, but there are many low quality bases (constantly Q=14 "/"), and the worst part is that instead of being towards the end, they seem a bit randomly distributed. When comparing PhiX in a 2x150bp NextSeq with a 2x250bp MiSeq, after alignment I see a 0.2-0.3% error rate with MiSeq and 0.9-1% error rate with NextSeq (1M sampled reads). In the "randomly" distributed Q=14 bases I seem to notice more A to T transitions, but I didn't have time to gather more systematic statistics... If I do quality trim on the MiSeq I can easily get higher quality data, with the NextSeq since its randomly distributed is harder...

We've complained to the Illumina people, let's see what they say...
dsobral is offline   Reply With Quote