distmat |
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distmat calculates the evolutionary distance between every pair of sequences in a multiple sequence alignment. A variety of methods to estimate distance may be selected, and differ in how they correct the observed substitution rates to more accurately reflect the true evolutionary distance. An output file containing a distance matrix for the set of sequences is written. The distances are expressed in terms of the number of substitutions per 100 bases or amino acids.
For more divergent sequences, the probability of there being multiple substitutions at an alignment site increases. The distance will then be misestimate the true evolutionary distance between the sequences. A number of methods are available in distmat to correct the observed substitution rate to more accurately reflect the true evolutionary distance.
S = m/(npos + gaps*gap_penalty) (1) m - score of matches (1 for an exact match, a fraction for partial matches and 0 for no match) npos - number of positions included in m gaps - number of gaps in the sequences gap_penalty - the score given to a gapped position
D = uncorrected distance = p-distance = 1-S (2)
The score of match includes all exact matches. For nucleotides, if the flag "-ambiguous" is used then partial matches are included in the score. For example, a match of M (A or C) with A will increment m by 0.5 (0.5*1.0). Gaps are not included in the calculation unless a non zero value is given with "-gapweight". It should be noted that end gaps and internal gaps will be weighted by the same amount. So it is recommended that this be used with "-sbegin"and "-send" to specify the start and end of the region to calculate the distance from.
distance = -b ln (1-D/b) D - uncorrected distance b - constant. b= 3/4 for nucleotides and 19/20 for proteins.
Partial matches and gap positions can be taken into account in the calculation of D, by setting the "-ambiguous" and "-gapweight" flags (see "uncorrected distance" method).
Reference:
"Phylogenetic Inference", Swofford, Olsen, Waddell, and
Hillis, in Molecular Systematics, 2nd ed., Sinauer Ass., Inc., 1996, Ch. 11.
A = 1, T = 2, C = 3, G = 4 b = 0.5(1.- Sum(i=A,G)(fraction[i]^2 + D^2/h) h = Sum(i=A,C)Sum(k=T,G) (0.5 * pair_frequency[i,k]^2/(fraction[i]*fraction[k])) distance = -b ln(1.-D/b) pair_frequency[i,k] - frequency of the i and k base pair at sites in the alignement of the pair of sequences. fraction[i] - average content of the base i in both sequences
Reference:
F. Tajima and M. Nei, Mol. Biol. Evol. 1984, 1, 269.
P = transitions/npos Q = transversions/npos npos - number of positions scored distance = -0.5 ln[ (1-2P-Q)*sqrt(1-2Q)]
Reference:
M. kimura, J. Mol. Evol. 1980, 16, 111.
P = transitions/npos Q = transversions/npos npos - number of positions scored GC1 = GC fraction in sequence 1 GC2 = GC fraction in sequence 2 C = GC1 + GC2 - 2*GC1*GC2 distance = -C ln(1-P/C-Q) - 0.5(1-C) ln(1-2Q)
Reference:
K. Tamura, Mol. Biol. Evol. 1992, 9, 678.
L = average substituition = transition_rate + 2 * transversion_rate a = (average L)^2/(variance of L) P = transitions/npos Q = transversions/npos npos - number of positions scored distance = 0.5 * a ((1-2P-Q)^(-1/a) + 0.5 (1-2Q)^(-1/a) -3/2)
It is suggested [Jin et al.], in general, that the distance be calculated with an a-value of 1. However, the user can specify their own value, using the "-parametera" option, or calculate for each pair of sequence, using "-calculatea".
Reference:
L. Jin and M. Nei, Mol. Biol. Evol. 1990, 7, 82.
S = m/npos m - exact match npos - number of positions scored D = 1-S distance = -ln(1 - D - 0.2D^2)
Reference:
M. Kimura, The Neutral Theory of Molecular Evolution, Camb. Uni. Press,
Camb., 1983.
% distmat pax.align Create a distance matrix from a multiple sequence alignment Multiple substitution correction methods for proteins 0 : Uncorrected 1 : Jukes-Cantor 2 : Kimura Protein Method to use [0]: 2 Phylip distance matrix output file [pax.distmat]: |
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Go to the output files for this example
Create a distance matrix from a multiple sequence alignment Version: EMBOSS:6.4.0.0 Standard (Mandatory) qualifiers (* if not always prompted): [-sequence] seqset File containing a sequence alignment. * -nucmethod menu [0] Multiple substitution correction methods for nucleotides. (Values: 0 (Uncorrected); 1 (Jukes-Cantor); 2 (Kimura); 3 (Tamura); 4 (Tajima-Nei); 5 (Jin-Nei Gamma)) * -protmethod menu [0] Multiple substitution correction methods for proteins. (Values: 0 (Uncorrected); 1 (Jukes-Cantor); 2 (Kimura Protein)) [-outfile] outfile [*.distmat] Phylip distance matrix output file Additional (Optional) qualifiers (* if not always prompted): * -ambiguous boolean [N] Option to use the ambiguous codes in the calculation of the Jukes-Cantor method or if the sequences are proteins. * -gapweight float [0.] Option to weight gaps in the uncorrected (nucleotide) and Jukes-Cantor distance methods. (Any numeric value) * -position integer [123] Choose base positions to analyse in each codon i.e. 123 (all bases), 12 (the first two bases), 1, 2, or 3 individual bases. (Any integer value) * -calculatea boolean [N] This will force the calculation of parameter 'a' in the Jin-Nei Gamma distance calculation, otherwise the default is 1.0 (see -parametera option). * -parametera float [1.0] User defined parameter 'a' to be use in the Jin-Nei Gamma distance calculation. The suggested value to be used is 1.0 (Jin et al.) and this is the default. (Any numeric value) Advanced (Unprompted) qualifiers: (none) Associated qualifiers: "-sequence" associated qualifiers -sbegin1 integer Start of each sequence to be used -send1 integer End of each sequence to be used -sreverse1 boolean Reverse (if DNA) -sask1 boolean Ask for begin/end/reverse -snucleotide1 boolean Sequence is nucleotide -sprotein1 boolean Sequence is protein -slower1 boolean Make lower case -supper1 boolean Make upper case -sformat1 string Input sequence format -sdbname1 string Database name -sid1 string Entryname -ufo1 string UFO features -fformat1 string Features format -fopenfile1 string Features file name "-outfile" associated qualifiers -odirectory2 string Output directory General qualifiers: -auto boolean Turn off prompts -stdout boolean Write first file to standard output -filter boolean Read first file from standard input, write first file to standard output -options boolean Prompt for standard and additional values -debug boolean Write debug output to program.dbg -verbose boolean Report some/full command line options -help boolean Report command line options and exit. More information on associated and general qualifiers can be found with -help -verbose -warning boolean Report warnings -error boolean Report errors -fatal boolean Report fatal errors -die boolean Report dying program messages -version boolean Report version number and exit |
Qualifier | Type | Description | Allowed values | Default | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Standard (Mandatory) qualifiers | ||||||||||||||||
[-sequence] (Parameter 1) |
seqset | File containing a sequence alignment. | Readable set of sequences | Required | ||||||||||||
-nucmethod | list | Multiple substitution correction methods for nucleotides. |
|
0 | ||||||||||||
-protmethod | list | Multiple substitution correction methods for proteins. |
|
0 | ||||||||||||
[-outfile] (Parameter 2) |
outfile | Phylip distance matrix output file | Output file | <*>.distmat | ||||||||||||
Additional (Optional) qualifiers | ||||||||||||||||
-ambiguous | boolean | Option to use the ambiguous codes in the calculation of the Jukes-Cantor method or if the sequences are proteins. | Boolean value Yes/No | No | ||||||||||||
-gapweight | float | Option to weight gaps in the uncorrected (nucleotide) and Jukes-Cantor distance methods. | Any numeric value | 0. | ||||||||||||
-position | integer | Choose base positions to analyse in each codon i.e. 123 (all bases), 12 (the first two bases), 1, 2, or 3 individual bases. | Any integer value | 123 | ||||||||||||
-calculatea | boolean | This will force the calculation of parameter 'a' in the Jin-Nei Gamma distance calculation, otherwise the default is 1.0 (see -parametera option). | Boolean value Yes/No | No | ||||||||||||
-parametera | float | User defined parameter 'a' to be use in the Jin-Nei Gamma distance calculation. The suggested value to be used is 1.0 (Jin et al.) and this is the default. | Any numeric value | 1.0 | ||||||||||||
Advanced (Unprompted) qualifiers | ||||||||||||||||
(none) | ||||||||||||||||
Associated qualifiers | ||||||||||||||||
"-sequence" associated seqset qualifiers | ||||||||||||||||
-sbegin1 -sbegin_sequence |
integer | Start of each sequence to be used | Any integer value | 0 | ||||||||||||
-send1 -send_sequence |
integer | End of each sequence to be used | Any integer value | 0 | ||||||||||||
-sreverse1 -sreverse_sequence |
boolean | Reverse (if DNA) | Boolean value Yes/No | N | ||||||||||||
-sask1 -sask_sequence |
boolean | Ask for begin/end/reverse | Boolean value Yes/No | N | ||||||||||||
-snucleotide1 -snucleotide_sequence |
boolean | Sequence is nucleotide | Boolean value Yes/No | N | ||||||||||||
-sprotein1 -sprotein_sequence |
boolean | Sequence is protein | Boolean value Yes/No | N | ||||||||||||
-slower1 -slower_sequence |
boolean | Make lower case | Boolean value Yes/No | N | ||||||||||||
-supper1 -supper_sequence |
boolean | Make upper case | Boolean value Yes/No | N | ||||||||||||
-sformat1 -sformat_sequence |
string | Input sequence format | Any string | |||||||||||||
-sdbname1 -sdbname_sequence |
string | Database name | Any string | |||||||||||||
-sid1 -sid_sequence |
string | Entryname | Any string | |||||||||||||
-ufo1 -ufo_sequence |
string | UFO features | Any string | |||||||||||||
-fformat1 -fformat_sequence |
string | Features format | Any string | |||||||||||||
-fopenfile1 -fopenfile_sequence |
string | Features file name | Any string | |||||||||||||
"-outfile" associated outfile qualifiers | ||||||||||||||||
-odirectory2 -odirectory_outfile |
string | Output directory | Any string | |||||||||||||
General qualifiers | ||||||||||||||||
-auto | boolean | Turn off prompts | Boolean value Yes/No | N | ||||||||||||
-stdout | boolean | Write first file to standard output | Boolean value Yes/No | N | ||||||||||||
-filter | boolean | Read first file from standard input, write first file to standard output | Boolean value Yes/No | N | ||||||||||||
-options | boolean | Prompt for standard and additional values | Boolean value Yes/No | N | ||||||||||||
-debug | boolean | Write debug output to program.dbg | Boolean value Yes/No | N | ||||||||||||
-verbose | boolean | Report some/full command line options | Boolean value Yes/No | Y | ||||||||||||
-help | boolean | Report command line options and exit. More information on associated and general qualifiers can be found with -help -verbose | Boolean value Yes/No | N | ||||||||||||
-warning | boolean | Report warnings | Boolean value Yes/No | Y | ||||||||||||
-error | boolean | Report errors | Boolean value Yes/No | Y | ||||||||||||
-fatal | boolean | Report fatal errors | Boolean value Yes/No | Y | ||||||||||||
-die | boolean | Report dying program messages | Boolean value Yes/No | Y | ||||||||||||
-version | boolean | Report version number and exit | Boolean value Yes/No | N |
The quality of the alignment is of paramount importance in obtaining meaningful information from this analysis.
PileUp MSF: 603 Type: P Check: 9004 .. Name: PAX4_HUMAN oo Len: 603 Check: 6594 Weight: 11.2 Name: PAX6_HUMAN oo Len: 603 Check: 7176 Weight: 9.1 Name: PAX3_HUMAN oo Len: 603 Check: 7760 Weight: 9.5 Name: PAX7_HUMAN oo Len: 603 Check: 4677 Weight: 13.7 Name: PAX1_HUMAN oo Len: 603 Check: 9671 Weight: 8.7 Name: PAX9_HUMAN oo Len: 603 Check: 565 Weight: 12.0 Name: PAX2_HUMAN oo Len: 603 Check: 9553 Weight: 8.7 Name: PAX5_HUMAN oo Len: 603 Check: 448 Weight: 11.2 Name: PX8A_HUMAN oo Len: 603 Check: 6763 Weight: 7.5 Name: PX8D_HUMAN oo Len: 603 Check: 5797 Weight: 7.9 // PAX4_HUMAN .......... .......... .........M HQDGISSMNQ LGGLFVNGRP PAX6_HUMAN .......... .......... .......... MQNSHSGVNQ LGGVFVNGRP PAX3_HUMAN MTTLAGAVPR MMRPGPGQNY PRSGFPLEVS TPLGQGRVNQ LGGVFINGRP PAX7_HUMAN MAALPGTVPR MMRPAPGQNY PRTGFPLEVS TPLGQGRVNQ LGGVFINGRP PAX1_HUMAN .......... .......... .......... MEQTYGEVNQ LGGVFVNGRP PAX9_HUMAN .......... .......... .......... MEPAFGEVNQ LGGVFVNGRP PAX2_HUMAN .......... ........MD MHCKADPFSA MHPGHGGVNQ LGGVFVNGRP PAX5_HUMAN .......... ........MD LEKNYPTPRT SRTGHGGVNQ LGGVFVNGRP PX8A_HUMAN .......... .......... .....MPHNS IRSGHGGLNQ LGGAFVNGRP PX8D_HUMAN .......... .......... .....MPHNS IRSGHGGLNQ LGGAFVNGRP PAX4_HUMAN LPLDTRQQIV RLAVSGMRPC DISRILKVSN GCVSKILGRY YRTGVLEPKG PAX6_HUMAN LPDSTRQKIV ELAHSGARPC DISRILQVSN GCVSKILGRY YETGSIRPRA PAX3_HUMAN LPNHIRHKIV EMAHHGIRPC VISRQLRVSH GCVSKILCRY QETGSIRPGA PAX7_HUMAN LPNHIRHKIV EMAHHGIRPC VISRQLRVSH GCVSKILCRY QETGSIRPGA PAX1_HUMAN LPNAIRLRIV ELAQLGIRPC DISRQLRVSH GCVSKILARY NETGSILPGA PAX9_HUMAN LPNAIRLRIV ELAQLGIRPC DISRQLRVSH GCVSKILARY NETGSILPGA PAX2_HUMAN LPDVVRQRIV ELAHQGVRPC DISRQLRVSH GCVSKILGRY YETGSIKPGV PAX5_HUMAN LPDVVRQRIV ELAHQGVRPC DISRQLRVSH GCVSKILGRY YETGSIKPGV PX8A_HUMAN LPEVVRQRIV DLAHQGVRPC DISRQLRVSH GCVSKILGRY YETGSIRPGV PX8D_HUMAN LPEVVRQRIV DLAHQGVRPC DISRQLRVSH GCVSKILGRY YETGSIRPGV PAX4_HUMAN IGGSKPR.LA TPPVVARIAQ LKGECPALFA WEIQRQLCAE GLCTQDKTPS PAX6_HUMAN IGGSKPR.VA TPEVVSKIAQ YKRECPSIFA WEIRDRLLSE GVCTNDNIPS PAX3_HUMAN IGGSKPKQVT TPDVEKKIEE YKRENPGMFS WEIRDKLLKD AVCDRNTVPS PAX7_HUMAN IGGSKPRQVA TPDVEKKIEE YKRENPGMFS WEIRDRLLKD GHCDRSTVPS PAX1_HUMAN IGGSKPR.VT TPNVVKHIRD YKQGDPGIFA WEIRDRLLAD GVCDKYNVPS [Part of this file has been deleted for brevity] PX8A_HUMAN VSSSSSTPSS LSSSAFLDLQ QVGSGVPPFN AFPHAASVYG QFTGQALLSG PX8D_HUMAN ....KSAPGS RPS....... .....MP... .FPMLPPCTG SSRARPSSQG PAX4_HUMAN .......... .......... .....ERCLS DTPPKACLKP CWDCGSFLLP PAX6_HUMAN .......... .......... .SFTMANNLP MQPPVPSQTS SYSCMLPTSP PAX3_HUMAN NGL.SPQVM. .......... GLLTNHGGVP HQPQTDYALS PLTGGLEPTT PAX7_HUMAN NGL.SPQVM. .......... SILGNPSAVP PQPQADFSIS PLHGGLDSAT PAX1_HUMAN .......... .......... GAGVAVHGGE LAAAMTFKHR EGTDRKPP.. PAX9_HUMAN .......... .......... ......HNCD IPASLAFKGM QAARE..... PAX2_HUMAN .......... .......... GSYPTSTLAG MVPGSEFSGN PYSHPQYTAY PAX5_HUMAN .......... .......... GSYSAPTLTG MVPGSEFSGS PYSHPQYSSY PX8A_HUMAN REMVGPTLPG YPPHIPTSGQ GSYASSAIAG MVAGSEYSGN AYGHTPYSSY PX8D_HUMAN ERWWGPRCP. .......... DTHPTSPPAD RAAMPPLPSQ AWWQEVN... PAX4_HUMAN VIAPSCVDVA WP.CLDASLA HHLIGGAGKA TPTHFS.... .......... PAX6_HUMAN SVNGRSYDTY TPPHMQTHMN SQPMGTSGTT STGLISPGVS VPVQVPGSEP PAX3_HUMAN TVSASCSQRL DHMKSLDSLP TSQSYCPPTY STTGYSMDPV TGYQYGQYGQ PAX7_HUMAN SISASCSQRA DSIKPGDSLP TSQAYCPPTY STTGYSVDPV AGYQYGQYGQ PAX1_HUMAN ..SSGSKAPD ALSSLH.... ....GLPIPA STS....... .......... PAX9_HUMAN ..GSHSVTAS AL........ .......... .......... .......... PAX2_HUMAN NEAWRFSNPA LLSSPYYYSA APR.SAPAAR AAAYDRH... .......... PAX5_HUMAN NDSWRFPNPG LLGSPYYYSA AARGAAPPAA ATAYDRH... .......... PX8A_HUMAN SEAWGFPNSS LLSSPYYYSS TSRPSAPPTT ATAFDHL... .......... PX8D_HUMAN ..TLAMPMAT PPTPP..... TARPGASPTP AC........ .......... PAX4_HUMAN .....HWP.. .......... .......... .......... .......... PAX6_HUMAN DMS.QYWPRL Q......... .......... .......... .......... PAX3_HUMAN S...KPWTF. .......... .......... .......... .......... PAX7_HUMAN SECLVPWASP VPIPSPTPRA SCLFMESYKV VSGWGMSISQ MEKLKSSQME PAX1_HUMAN .......... .......... .......... .......... .......... PAX9_HUMAN .......... .......... .......... .......... .......... PAX2_HUMAN .......... .......... .......... .......... .......... PAX5_HUMAN .......... .......... .......... .......... .......... PX8A_HUMAN .......... .......... .......... .......... .......... PX8D_HUMAN .......... .......... .......... .......... .......... PAX4_HUMAN ... PAX6_HUMAN ... PAX3_HUMAN ... PAX7_HUMAN QFT PAX1_HUMAN ... PAX9_HUMAN ... PAX2_HUMAN ... PAX5_HUMAN ... PX8A_HUMAN ... PX8D_HUMAN ... |
Distance Matrix --------------- Using the Kimura correction method Gap weighting is 0.000000 1 2 3 4 5 6 7 8 9 10 0.00 96.15 137.48 128.72 161.14 160.37 157.55 154.23 164.32 152.68 PAX4_HUMAN 1 0.00 111.86 109.96 156.25 149.70 143.75 135.71 150.60 146.87 PAX6_HUMAN 2 0.00 26.21 131.54 143.54 162.95 151.39 163.56 159.78 PAX3_HUMAN 3 0.00 145.45 138.76 158.79 149.96 167.26 161.82 PAX7_HUMAN 4 0.00 44.29 120.84 123.00 131.69 130.22 PAX1_HUMAN 5 0.00 123.56 130.21 131.64 130.17 PAX9_HUMAN 6 0.00 36.43 53.12 64.32 PAX2_HUMAN 7 0.00 60.88 73.82 PAX5_HUMAN 8 0.00 20.37 PX8A_HUMAN 9 0.00 PX8D_HUMAN 10 |
The input sequences must of course be aligned before running this program. The quality of the alignment is of paramount importance in obtaining meaningful information from this analysis.
For nucleotides, the -position flag selects base positions to analyse in each codon, i.e. 123 (all bases), 12 (the first two bases), 1, 2, or 3 individual bases.
Program name | Description |
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Please report all bugs to the EMBOSS bug team (emboss-bug © emboss.open-bio.org) not to the original author.