# Removing sequences or OTUs from SELECTED groups only?

**URL:** <https://forum.mothur.org/t/removing-sequences-or-otus-from-selected-groups-only/3319>\
**Category:** Commands in mothur\
**Created:** [July 6, 2017, 2:40pm UTC](https://forum.mothur.org/t/removing-sequences-or-otus-from-selected-groups-only/3319 "2017-07-06T14:40:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![mniku](https://avatars.discourse-cdn.com/v4/letter/m/e68b1a/32.png) [@mniku](https://forum.mothur.org/u/mniku)\
**Post date:** [July 6, 2017, 2:40pm UTC](https://forum.mothur.org/t/removing-sequences-or-otus-from-selected-groups-only/3319/1 "2017-07-06T14:40:16Z")

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How can I delete sequences or OTUs from some of the sample groups only (not all of them)? Let’s say my data includes very different types of samples, and I want to remove potential contaminants only from low-biomass ones, but not from high-biomass ones.

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**Author:** ![Kendra](https://yyz2.discourse-cdn.com/flex036/user_avatar/forum.mothur.org/kendra/32/112_2.png) [@Kendra](https://forum.mothur.org/u/Kendra)\
**Post date:** [July 7, 2017, 2:25pm UTC](https://forum.mothur.org/t/removing-sequences-or-otus-from-selected-groups-only/3319/2 "2017-07-07T14:25:38Z")

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I doubt there’s a function to do this in mothur because it’s fairly difficult to justify treating data differently for different samples. You could do it in R with some logic based filtering