# OTUs Classification

**URL:** <https://forum.mothur.org/t/otus-classification/3019>\
**Category:** Commands in mothur\
**Created:** [October 17, 2016, 9:15pm UTC](https://forum.mothur.org/t/otus-classification/3019 "2016-10-17T21:15:45Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Rain](https://avatars.discourse-cdn.com/v4/letter/r/e95f7d/32.png) [@Rain](https://forum.mothur.org/u/Rain)\
**Post date:** [October 17, 2016, 9:15pm UTC](https://forum.mothur.org/t/otus-classification/3019/1 "2016-10-17T21:15:45Z")

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Dear All,

I have a question confused me for a while that the OTU classification could be further into one specific genus, which means that a genus could be separated into several OTUs. I am wondering whether it is normal or not? The commands are:

> mothur cluster.split(fasta=test.unique.filter.unique.precluster.fasta,count=test.unique.filter.unique.precluster.count\_table,taxonomy=test.unique.filter.unique.precluster.seed\_v123.wang.taxonomy,splitmethod=classify,taxlevel=6,large=T,processors=8)  
> mothur  
> classify.otu(list=test.unique.filter.unique.precluster.an.unique\_list.list,count=test.unique.filter.unique.precluster.count\_table,taxonomy=test.unique.filter.unique.precluster.seed\_v123.wang.taxonomy,label=0.03,cutoff=80,threshold=90)

Just like following Otu0001 and Otu0003, both of which are belonged to Pseudomonas.  
Otu0001 9367 Bacteria(100);Proteobacteria(100);Gammaproteobacteria(100);Pseudomonadales(100);Pseudomonadaceae(100);Pseudomonas(94);Pseudomonas\_unclassified(94);Pseudomonas\_unclassified(94);  
Otu0002 6477 Bacteria(100);Proteobacteria(100);Gammaproteobacteria(100);Pseudomonadales(100);Pseudomonadaceae(100);Pseudomonadaceae\_unclassified(91);Pseudomonadaceae\_unclassified(91);Pseudomonadaceae\_unclassified(91);  
Otu0003 2626 Bacteria(100);Proteobacteria(100);Gammaproteobacteria(100);Pseudomonadales(100);Pseudomonadaceae(100);Pseudomonas(80);Pseudomonas\_unclassified(80);Pseudomonas\_unclassified(80);

Thanks,  
Rain

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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:** [October 18, 2016, 3:29pm UTC](https://forum.mothur.org/t/otus-classification/3019/2 "2016-10-18T15:29:20Z")

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This is why we use OTUs, because we can’t distinguish “species” when we just look at the taxonomic classification. Totally normal