Multiple Sequence Alignment with External Applications

These functions call their respective program from R to align a set of nucleotide sequences of class "DNAbin". The application(s) must be installed seperately and it is highly recommended to do this so that the executables are in a directory located on the PATH of the system.

clustal(x, pw.gapopen = 10, pw.gapext = 0.1,
        gapopen = 10, gapext = 0.2, exec = NULL,
        MoreArgs = "", quiet = TRUE, original.ordering = TRUE)
clustalomega(x, exec = NULL, MoreArgs = "", quiet = TRUE)
muscle(x, exec = "muscle", MoreArgs = "", quiet = TRUE,
       original.ordering = TRUE)
tcoffee(x, exec = "t_coffee", MoreArgs = "", quiet = TRUE,
        original.ordering = TRUE)

an object of class "DNAbin".

pw.gapopen, pw.gapext

gap opening and gap extension penalties used by Clustal during pairwise alignments.

gapopen, gapext

idem for global alignment.


a character string giving the name of the program, with its path if necessary. clustal tries to guess it depending on the operating system (see details).


a character string giving additional options.


a logical: the default is to not print on R's console the messages from the external program.


a logical specifying whether to return the aligned sequences in the same order than in x.


It is highly recommended to install the executables properly so that they are in a directory located on the PATH (i.e., accessible from any other directory). Alternatively, the full path to the executable may be given (e.g., exec = "~/muscle/muscle"), or a (symbolic) link may be copied in the working directory. For Debian and its derivatives (e.g., Ubuntu), it is recommended to use the binaries distributed by Debian.

clustal tries to guess the name of the executable program depending on the operating system. Specifically, the followings are used: ``clustalw'' under Linux, ``clustalw2'' under MacOS, or ``clustalw2.exe'' under Windows.

For clustalomega, ``clustalo[.exe]'' is the default on all systems (with no specific path) since it seems there is no Windows installer.

The computations are done in a temporary directory which is deleted when R is quit. So it is possible to find the files created by the last call in the directory printed by tempdir().

When called without arguments (i.e., clustal(), …), the function prints the options of the program which may be passed to MoreArgs.


an object of class "DNAbin" with the aligned sequences.


clustalomega is actually for AA sequences only.


Chenna, R., Sugawara, H., Koike, T., Lopez, R., Gibson, T. J., Higgins, D. G. and Thompson, J. D. (2003) Multiple sequence alignment with the Clustal series of programs. Nucleic Acids Research 31, 3497--3500.

Edgar, R. C. (2004) MUSCLE: Multiple sequence alignment with high accuracy and high throughput. Nucleic Acids Research, 32, 1792--1797.

Notredame, C., Higgins, D. and Heringa, J. (2000) T-Coffee: A novel method for multiple sequence alignments. Journal of Molecular Biology, 302, 205--217.

Sievers, F., Wilm, A., Dineen, D., Gibson, T. J., Karplus, K., Li, W., Lopez, R., McWilliam, H., Remmert, M., S\"oding, J., Thompson, J. D. and Higgins, D. G. (2011) Fast, scalable generation of high-quality protein multiple sequence alignments using Clustal Omega. Molecular Systems Biology, 7, 539.

See Also

image.DNAbin, del.gaps, all.equal.DNAbin, alex, alview, checkAlignment

  • clustal
  • clustalomega
  • muscle
  • tcoffee
### display the options:

### open gaps more easily:
clustal(woodmouse, pw.gapopen = 1, pw.gapext = 1)
### T-Coffee requires negative values (quite slow; muscle is much faster):
tcoffee(woodmouse,  MoreArgs = "-gapopen=-10 -gapext=-2")
# }
Documentation reproduced from package ape, version 4.1, License: GPL (>= 2)

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