dist.shared

The dist.shared command will generate a phylip-formatted distance matrix that describes the dissimilarity (1-similarity) among multiple groups. This command will calculate any of the calculators describing the similarity in community membership or structure.

To run through the example below, download Example Data.

Default settings

You can generate a shared file with the following commands:

mothur > cluster.split(fasta=final.fasta, count=final.count_table, taxonomy=final.taxonomy, cutoff=0.03)
mothur > make.shared(list=final.opti_mcc.list, count=final.count_table)

Then you can run the dist.shared command:

mothur > dist.shared(shared=final.opti_mcc.shared)

This will generate phylip-formatted lower-triangle distance matrices for the classical jaccard and Yue & Clayton theta values. The output files are as follows:

final.opti_mcc.jclass.0.03.dist

19
F3D0
F3D1	0.466102
F3D141	0.518519	0.544681
F3D142	0.549587	0.588983	0.495455
F3D143	0.554113	0.589286	0.468293	0.540670
F3D144	0.532258	0.564315	0.457399	0.524229	0.478469
F3D145	0.537879	0.568093	0.455696	0.500000	0.468468	0.458333
F3D146	0.469136	0.480687	0.414414	0.482301	0.490741	0.472103	0.469636
F3D147	0.503546	0.546763	0.471483	0.528090	0.536965	0.473684	0.465950	0.449438
F3D148	0.507353	0.546816	0.443548	0.527344	0.468085	0.464567	0.427481	0.426877	0.400000
F3D149	0.463602	0.526923	0.399160	0.517928	0.476395	0.434959	0.452471	0.395918	0.412186	0.388679
F3D150	0.463115	0.518672	0.408072	0.502165	0.469767	0.432314	0.432099	0.404348	0.396154	0.376518	0.350000
F3D2	0.391129	0.399160	0.471774	0.549020	0.547325	0.532567	0.488806	0.442231	0.474048	0.471223	0.432836	0.454902
F3D3	0.511211	0.445545	0.528302	0.550239	0.548223	0.576577	0.561702	0.478873	0.561538	0.550607	0.529167	0.527027	0.460526
F3D5	0.423423	0.396135	0.486239	0.527523	0.517073	0.515556	0.485106	0.409302	0.509506	0.477733	0.473251	0.431818	0.381579	0.402116
F3D6	0.416309	0.426009	0.469298	0.540773	0.504630	0.510549	0.487903	0.423581	0.483395	0.457031	0.427419	0.410480	0.362869	0.426471	0.338235
F3D7	0.504505	0.460784	0.500000	0.514706	0.540816	0.537037	0.555556	0.464455	0.533333	0.526749	0.516807	0.506849	0.473913	0.386364	0.376344	0.410891
F3D8	0.387665	0.403670	0.482456	0.515419	0.504673	0.504274	0.500000	0.401786	0.460377	0.474708	0.433198	0.450644	0.361702	0.448780	0.328358	0.333333	0.369231
F3D9	0.386266	0.429825	0.458874	0.523404	0.506787	0.506224	0.478088	0.400000	0.468864	0.459770	0.430830	0.421277	0.381148	0.438095	0.352381	0.270142	0.392157	0.284360     

final.opti_mcc.thetayc.0.03.dist

19
F3D0
F3D1	0.467784
F3D141	0.200970	0.530882
F3D142	0.239879	0.520864	0.156886
F3D143	0.173126	0.585864	0.072479	0.111842
F3D144	0.238960	0.613608	0.144858	0.162919	0.079240
F3D145	0.232203	0.588647	0.107915	0.097159	0.066403	0.029717
F3D146	0.184757	0.558084	0.099157	0.179974	0.060261	0.096863	0.091673
F3D147	0.220980	0.589134	0.146073	0.098548	0.076317	0.049223	0.043311	0.114373
F3D148	0.205197	0.585151	0.058623	0.120294	0.042650	0.081693	0.066706	0.089601	0.073930
F3D149	0.205419	0.510710	0.028117	0.144051	0.062294	0.123908	0.098087	0.075535	0.127204	0.058077
F3D150	0.230092	0.562980	0.116270	0.222369	0.120337	0.219990	0.177784	0.117441	0.200202	0.178459	0.093350
F3D2	0.475966	0.380856	0.442097	0.418148	0.523964	0.529063	0.480563	0.560674	0.491112	0.520358	0.463331	0.526857
F3D3	0.501665	0.456360	0.378036	0.325260	0.462424	0.461422	0.384942	0.496843	0.432575	0.442618	0.381735	0.457285	0.159622
F3D5	0.389512	0.279060	0.341331	0.374956	0.432542	0.476654	0.420015	0.421352	0.462750	0.437170	0.329308	0.337508	0.311072	0.292658
F3D6	0.417659	0.402093	0.354543	0.245569	0.406905	0.441063	0.355320	0.427399	0.389443	0.435147	0.350073	0.354927	0.192843	0.151399	0.230311
F3D7	0.477928	0.508112	0.351954	0.255068	0.416624	0.443394	0.332710	0.445590	0.402846	0.424137	0.363060	0.371960	0.265586	0.121449	0.289060	0.086599
F3D8	0.531280	0.443728	0.455453	0.383646	0.516738	0.597693	0.499638	0.523192	0.570409	0.520859	0.445621	0.458872	0.479015	0.317462	0.270402	0.256547	0.212861
F3D9	0.478498	0.370645	0.401997	0.355820	0.474813	0.561227	0.463472	0.483257	0.533170	0.482968	0.397608	0.411368	0.373744	0.263416	0.183329	0.186051	0.185002	0.047525

Options

calc

Using the calc option allows one to select any of the calculators of similarity of community membership and structure. The different calculators can be separated with hyphens (i.e. “-“). For example the following command will generate distance matrices for the Jaccard coefficient using richness estimators, the Yue & Clayton theta, and the Bray-Curtis index:

mothur > dist.shared(shared=final.opti_mcc.shared, calc=jest-thetayc-braycurtis)

Keep in mind that these are distances, which are calculated as one minus the similarity value.

groups

At this point, if you run the following command:

mothur > get.group(shared=final.opti_mcc.shared)

You would have seen that there were 19 groups. If you just want the distances between groups F3D8 and F3D1, F3D8 and F3D0, or F3D1 and F3D0 enter the following (this is an admittedly silly example):

mothur > dist.shared(shared=final.opti_mcc.shared, groups=F3D8-F3D1)
mothur > dist.shared(shared=final.opti_mcc.shared, groups=F3D8-F3D0)
mothur > dist.shared(shared=final.opti_mcc.shared, groups=F3D0-F3D1)

Keep in mind that these will output to files with the same name. So, it is important to change the file name between commands. The following reverts to the default behavior:

mothur > dist.shared(shared=final.opti_mcc.shared, groups=all)

label

There may only be a couple of lines in your OTU data that you are interested in summarizing. There are two options. You could: (i) manually delete the lines you aren’t interested in from you rabund, sabund, list, or shared file; (ii) or use the label option.

mothur > dist.shared(shared=final.opti_mcc.shared, label=0.03)

output

The output option allows you specify the form of the matrix generated by dist.shared. By default, dist.shared will generate a phylip formatted lower triangle matrix. If you set output to “square” a phylip formatted square matrix will be generated. If you set output to “column” a column formatted distance matrix will be produced.

mothur > dist.shared(shared=final.opti_mcc.shared, output=column)

subsample

The subsample parameter allows you to enter the size pergroup of the sample or you can set subsample=T and mothur will use the size of your smallest group.

withreplacement

The withreplacement parameter allows you to indicate you want to subsample your data allowing for the same read to be included multiple times. Default=f.

iters

The iters parameter allows you to choose the number of times you would like to run the subsample. Default=1000.

processors

The processors option allows you to reduce the processing time by using multiple processors. Default processors=Autodetect number of available processors and use all available. You can use 2 processors with the following option:

mothur > dist.shared(shared=final.opti_mcc.shared, processors=2)

Running this command on my laptop doesn’t exactly cut the time in half, but it’s pretty close. There is no software limit on the number of processors that you can use.

Revisions

  • 1.24.0 - paralellized for Windows.
  • 1.29.0 - added subsampling parameters.
  • 1.30.0 - added column format to output parameter.
  • 1.33.0 - added Square Root Jensen-Shannon Divergence and jensen-shannon divergence calculators.
  • 1.40.0 - Speed and memory improvements for shared files. #357 , #347
  • 1.40.0 - Rewrite of threaded code. Default processors=Autodetect number of available processors and use all available.
  • 1.40.0 - Fixes segfault error for commands that use subsampling. #357 , #347
  • 1.42.0 - Adds withreplacement parameter to sub.sample command. #262
  • 1.43.0 - Modifies output files from dist.shared, summary.single and summary.shared. You may run with or without rarefaction, but not both. #607