Filter.shared
The filter.shared command is used to remove OTUs based on various criteria. It creates a .filter.shared file.
Default settings
The filter.shared command requires a shared file.
mothur > filter.shared(shared=final.an.shared)
Options
minabund
The minabund parameter allows you indicate the minimum abundance required for each sample in a given OTU. If any samples abundance falls below the minimum, the OTU is removed. Default=1.
mothur > filter.shared(shared=final.an.shared, minabund=1)
Let’s look at an example:
0.16 A 13 1 0 0 0 0 27 0 2 37 0 0 16 1
0.16 B 13 0 2 1 13 2 14 0 6 14 0 4 28 0
0.16 C 13 0 0 0 0 0 0 1 4 4 4 25 11 25
would become:
label Group numOtus Otu008 Otu009 Otu012 Otu242
0.16 A 4 2 37 16 29
0.16 B 4 6 14 28 36
0.16 C 4 4 4 11 55
where OTU242 is the “rare” OTU created by mothur to preserve the abundance of each group.
minpercent
The minpercent parameter allows you indicate the minimum relative abundance of an OTU. For example, if the OTUs total abundance across all samples is 8, and the total abundance across all OTUs is 1000, and minpercent=1. The OTU’s relative abundance is 0.008, the minimum is
0.01, so the OTU will be removed. Default=0.
mothur > filter.shared(shared=final.an.shared, minpercent=1)
minpercent=1 requires each OTU to have a minimum relative abundance of
0.01 or abundance > 2.42.
Let’s look at an example:
0.16 A 13 1 0 0 0 0 27 0 2 37 0 0 16 1
0.16 B 13 0 2 1 13 2 14 0 6 14 0 4 28 0
0.16 C 13 0 0 0 0 0 0 1 4 4 4 25 11 25
would become:
label Group numOtus Otu004 Otu006 Otu008 Otu009 Otu010 Otu011 Otu012 Otu013 Otu242
0.16 A 9 0 27 2 37 0 0 16 1 1
0.16 B 9 13 14 6 14 0 4 28 0 5
0.16 C 9 0 0 4 4 4 25 11 25 1
where OTU242 is the “rare” OTU created by mothur to preserve the abundance of each group.
mintotal
The mintotal parameter allows you indicate the minimum abundance required for a given OTU. If abundance across all samples falls below the minimum, the OTU is removed. Default=0.
mothur > filter.shared(shared=final.an.shared, mintotal=10)
Let’s look at an example:
0.16 A 13 1 0 0 0 0 27 0 2 37 0 0 16 1
0.16 B 13 0 2 1 13 2 14 0 6 14 0 4 28 0
0.16 C 13 0 0 0 0 0 0 1 4 4 4 25 11 25
would become:
label Group numOtus Otu004 Otu006 Otu008 Otu009 Otu011 Otu012 Otu013 Otu242
0.16 A 8 0 27 2 37 0 16 1 1
0.16 B 8 13 14 6 14 4 28 0 5
0.16 C 8 0 0 4 4 25 11 25 5
where OTU242 is the “rare” OTU created by mothur to preserve the abundance of each group.
minnumsamples
The minnumsamples parameter allows you indicate the minimum number of samples present in an OTU. If the number of samples present falls below the minimum, the OTU is removed. Default=0.
mothur > filter.shared(shared=final.an.shared, minnumsamples=2)
Let’s look at an example:
0.16 A 13 1 0 0 0 0 27 0 2 37 0 0 16 1
0.16 B 13 0 2 1 13 2 14 0 6 14 0 4 28 0
0.16 C 13 0 0 0 0 0 0 1 4 4 4 25 11 25
would become:
label Group numOtus Otu006 Otu008 Otu009 Otu011 Otu012 Otu013 Otu242
0.16 A 7 27 2 37 0 16 1 1
0.16 B 7 14 6 14 4 28 0 18
0.16 C 7 0 4 4 25 11 25 5
where OTU242 is the “rare” OTU created by mothur to preserve the abundance of each group.
minpercentsamples
The minpercentsamples parameter allows you indicate the minimum percentage of samples present in an OTU. For example, if the total number of samples is 10, the number present is 3, and the minpercentsamples=50. The OTU’s precent of samples is 0.333, the minimum is 0.50, so the OTU will be removed. Default=0.
mothur > filter.shared(shared=final.an.shared, minpercentsamples=50)
minpercentsamples=50 requires each OTU to have a minimum percent of samples present of 0.50 or > 1.5.
Let’s look at an example:
0.16 A 13 1 0 0 0 0 27 0 2 37 0 0 16 1
0.16 B 13 0 2 1 13 2 14 0 6 14 0 4 28 0
0.16 C 13 0 0 0 0 0 0 1 4 4 4 25 11 25
would become:
label Group numOtus Otu006 Otu008 Otu009 Otu011 Otu012 Otu013 Otu242
0.16 A 7 27 2 37 0 16 1 1
0.16 B 7 14 6 14 4 28 0 18
0.16 C 7 0 4 4 25 11 25 5
where OTU242 is the “rare” OTU created by mothur to preserve the abundance of each group.
makerare
The makerare parameter allows you indicate you want the abundances of any removed OTUs to be saved and a new “rare” OTU created with its abundances equal to the sum of the OTUs removed. This will preserve the number of reads in your dataset. Default=T.
rarepercent
The rarepercent parameter allows you indicate the percentage of otus to remove. The OTUs chosen to be removed are the rarest. For example if you have 1000 OTUs, rarepercent=20 would remove the 200 OTUs with the lowest abundance. Default=0.
keepties
The keepties parameter is used with the rarepercent parameter. It allows you indicate you want to keep the OTUs with the same abundance as the first ‘not rare’ OTU. For example if you have 10 OTUs, rarepercent=20 abundances of 20, 18, 15, 15, 10, 5, 3, 3, 3, 1. keepties=t, would remove the 10th OTU, but keep the 9th because its abundance ties the 8th OTU. keepties=f would remove OTUs 9 and 10. Default=T.
groups
The groups parameter allows you to specify which of the groups you would like included. The group names are separated by dashes.
mothur > filter.shared(shared=final.an.shared, mintotal=10, groups=A-B)
accnos
You may wish to list your groups in a file instead of manually typing them. This can be done by using an accnos file.
mothur > filter.shared(shared=final.an.shared, mintotal=10, accnos=myGroups.accnos)
label
The label parameter allows you to select what distance levels you would like, and are also separated by dashes.
mothur > filter.shared(shared=final.an.shared, mintotal=10, label=0.03)
Revisions
- 1.29.0 - First Introduced
- 1.31.0 - Added rarepercent and keepties parameters. https://forum.mothur.org/viewtopic.php?f=5&t=2007
- 1.37.0 - Modifies rareOtus label to prevent mothurConvert error. #137
- 1.40.0 - Speed and memory improvements for shared files. #357 , #347
- 1.41.0 - Adds accnos parameter to filter.shared. #293