RETREE -- Interactive Tree Rearrangement
(c) Copyright 1993 by Joseph Felsenstein and by the University of
Washington. Written by Joseph Felsenstein. Permission is granted to copy this
document provided that no fee is charged for it and that this copyright notice
is not removed.
RETREE reads in a tree, or allows the usur to construct one, and displays
this tree on the screen. The user then can specify how the tree is to be
rearraranged, rerooted or written out to a file.
The input trees are in one file ( with file identifier "intree"), the
output trees are written into another ("outtree": note the two t's). The user
can reroot, flip branches, change names of species, change or remove branch
lengths, and move around to look at various parts of the tree if it is too
large to fit on the screen.
A major use for this program will be to change rootedness of trees so that
a rooted tree derived from one program can be fed in as an unrooted tree to
another (you are asked about this when you give the command to write out the
tree onto the tree output file). It will also be useful for specifying the
length of a branch in a tree where you want a program like DNAML, DNAMLK,
FITCH, or CONTML to hold that branch length constant (see the L suboption of
the User Tree option in those programs. It will also be useful for changing
the order of species for purely cosmetic reasons for DRAWGRAM and DRAWTREE,
including using the Midpoint method of rooting the tree. It can be used to
write out a tree file in the Nexus format used by Paup and MacClade.
This program is compatible with fewer computer systems than the other
programs in PHYLIP. It can be adapted to PCDOS systems or to any system whose
screen or terminals emulate DEC VT52 or VT100 terminals (such as, for example,
Zenith Z19, Z29, and Z49 terminals, Telnet programs for logging in to remote
computers over a TCP/IP network, VT100-compatible windows in the X windowing
system, and any terminal compatible with ANSI standard terminals). For any
other screen types, there is a generic option which does not make use of screen
graphics characters to display the nucleotide states. This will be less
effective, as the nucleotide states will be less easy to see when displayed.
The user interaction starts with the program presenting a menu. The menu
looks like this:
Tree Rearrangement, version 3.5c
Settings for this run:
U Initial tree (arbitrary, user, specify)? User tree from tree file
N Use the Nexus format to write out trees? No
0 Graphics type (IBM PC, VT52, ANSI)? ANSI
W Width of terminal screen, of plotting area? 80, 80
L Number of lines on screen? 24
Are these settings correct? (type Y or the letter for one to change)
The 0 (Graphics type) option is the usual one and is described in the
main documentation file.
The U (initial tree) option allows the user to choose
whether the initial tree is to be arbitrary, interactively specified by the
user, or read from a tree file. Typing U causes the program to change among
the three possibilities in turn. Usually we will want to use a User Tree from
a file. It requires that you have available a tree file with the tree topology
of the initial tree, which must be a rooted tree. If you wish to set up some
other particular tree you can either use the "specify" choice in the initial
tree option (which is somewhat difficult to use) or rearrange a User Tree of an
arbitrary tree into the shape you want by using the rearrangement commands
The L (screen Lines) option allows the user to change the height of the
screen (in lines of characters) that is assumed to be available on the display.
This may be particularly helpful when displaying large trees on terminals that
have more than 24 lines per screen, or on workstation or X-terminal screens
that can emulate the ANSI terminals with more than 24 lines.
The N (Nexus) option allows the user to specify that the tree files that
are written by the program will be in the Nexus format defined by David
Swofford and Wayne and David Maddison for their programs PAUP and MacClade. A
tree file written in Nexus format should be directly readable by those
programs. (They also have options to read a regular PHYLIP tree file as well).
This option is off by default.
The W (screen and window Width) option specifies the width in characters
of the area which the trees will be plotted to fit into. This is by default 80
characters so that they will fit on a normal width terminal. The actual width
of the display on the terminal (normally 80 characters) will be regarded as a
window displaying part of the tree. Thus you could set the "plotting area" to
132 characters, and inform the program that the screen width is 80 characters.
Then the program will display only part of the tree at any one time. Below we
will show how to move the "window" and see other parts of the tree.
After the initial menu is displayed and the choices are made, the program
then sets up an initial tree and displays it. Below it will be a one-line menu
of possible commands, which looks like this:
NEXT? (Options: R . = U W O M T F B N H J K L C + ? X Q) (? for Help)
If you type "?" you will get a single screen showing a description of each of
these commands in a few words. Here are slightly more detailed descriptions:
- ("Rearrange"). This command asks for the number of a node which is to be
removed from the tree. It and everything to the right of it on the tree is
to be removed (by breaking the branch immediately below it). The command
also asks for the number of a node below which that group is to be
inserted. If an impossible number is given, the program refuses to carry
out the rearrangement and asks for a new command. The rearranged tree is
displayed: it will often have a different number of steps than the
original. If you wish to undo a rearrangement, use the Undo command, for
which see below.
- This command simply causes the current tree to be redisplayed. It is of
use when the tree has partly disappeared off of the top of the screen owing
to too many responses to commands being printed out at the bottom of the
- (toggle display of branch lengths). This option is available whenever the
tree has a full set of branch lengths. It toggles on and off whether the
tree displayed on the screen is shown with the relative branch lengths
roughly correct. (It cannot be better than roughly correct because the
display is in units of length of whole character widths on the screen). It
does not actually remove any branch lengths from the tree: if the tree
showing on the screen seems to have no branch lengths after use of the "="
option, if it were written out at that point, it would still have a full]
set of branch lengths.
- ("Undo"). This command reverses the effect of the most recent
rearrangement, outgroup re-rooting, or flipping of branches. It returns to
the previous tree topology. It will be of great use when rearranging the
tree and when a rearrangement proves worse than the preceding one -- it
permits you to abandon the new one and return to the previous one without
remembering its topology in detail. Some operations, such as the
simultaneous removal of lengths from all branches, cannot be reversed.
- ("Write"). This command writes out the current tree onto a tree output
file. If the file already has been written to by this run of RETREE, it
will ask you whether you want to replace the contents of the file, add the
tree to the end of the file, or not write out the tree to the file. It
will also ask you whether you want the tree to written out as Rooted or
Unrooted. If you choose Unrooted, it will write the outermost split of the
tree as a three-way split with the three branches being those that issue
from one of the nodes. This node will be the left (upper) interior node
which is next to the root, or the other one if there is no interior node to
the left (above) the root. The tree is written in the standard format used
by PHYLIP (a subset of the New Hampshire standard) or in the Nexus format.
A normal PHYLIP tree is in the proper format to serve as the User-Defined
Tree for setting up the initial tree in a subsequent run of the program.
- ("Outgroup"). This asks for the number of a node which is to be the
outgroup. The tree will be redisplayed with that node as the left
descendant of the bottom fork. Note that it is possible to use this to
make a multi-species group the outgroup (i.e., you can give the number of
an interior node of the tree as the outgroup, and the program will re-root
the tree properly with that on the left of the bottom fork.
- ("Midpoint root"). This reroots a tree that has a complete set of
branches using the Midpoint rooting method. That rooting method finds the
centroid of the tree -- the point that is equidistant from the two farthest
points of the tree, and roots the tree there. This has the effect of
making the two farthest tips stick out an equal distance to the right.
Note that as the tree is rerooted, the scale may change on the screen so
that it looks like it ahas suddenly gotted a bit longer. It will not have
actually changed in total length. This option is not in the menu if the
tree does not have a full set of branch lengths.
- ("Transpose"). This asks for a node number and then flips the two
branches at that node, so that the left-right order of branches at that
node is changed. This also does not actually change the tree topology but
it does change the appearance of the tree. However, unlike the F option
below the individual subtrees defined by those branches do not have any
further branches reversed in them.
- ("Flip"). This asks for a node number and then flips the entire subtree
at that node, so that the left-right order of branches in the whole subtree
is changed. This does not actually change the tree topology but it does
change the appearance of the tree. Note that it works differently than the
F option in the programs MOVE, DNAMOVE, and DOLMOVE, which is actually like
the T option mentioned below.
- ("Branch length"). This asks you for the number of a node which is at the
end of a branch length, then asks you whether you want to enter a branch
length for that branch, change the branch length for that branch (if there
is one already) or remove the branch length from the branch.
- ("Name"). This asks you which species you want to change the name for
(referring to it by the number for that branch), then gives you the option
of either removing the name, typing a new name, or leaving the name as is.
Be sure not to try to enter a parentheses ("(" or ")"), a colon (":"), a
comma (",") or a semicolon (";") in a name, as those may be mistaken for
structural information about the tree.
- H, J, K, or L.
- These are the movement commands for scrolling the "window"
across a tree. H moves the "window" leftwards (though not beyond column 1,
J moves it down, K up, and L right. The "window" will move 20 columns or
rows at a time, and the tree will be redrawn in the new "window".
- ("Clade"). The C command instructs the program to print out only that
part of the tree (the "clade") from a certain node on up. The program will
prompt you for the number of this node. Remember that thereafter you are
not looking at the whole tree. To go back to looking at the whole tree
give the C command again and enter "0" for the node number when asked.
Most users will not want to use this option unless forced to, as much can
be accomplished with the window movement commands H, J, K, and L.
- ("next tree"). This causes the program to read in the next tree in the
input file, if there is one.
- ("Help"). Prints a one-screen summary of what the commands do, a few
words for each command.
- ("Exit"). Exit from program. If the current tree has not yet been saved
into a file, the program will first ask you whether it should be saved.
- ("Quit"). A synonym for X. Same as the eXit command.
ADAPTING THE PROGRAM TO YOUR COMPUTER AND TO YOUR TERMINAL
As we have seen, the initial menu of the program allows you to choose
among four screen types (PCDOS, Ansi, VT52 and none). If you want to avoid
having to make this choice every time, you can change some of the constants at
the beginning of the program to have it initialize itself in the proper way.
At the beginning of the program are three constants that determine which kind
of screen graphics the program will use. They are ibmpc0, vt520, and ansi0.
In the distribution version of the programs, ansi0 is set to "true" and the
others to "false", in the statements:
#define ibmpc0 false
#define ansi0 true
#define vt520 false
so that the version will work with ANSI compatible terminals.
On the other hand if you have a terminal compatible with DEC's VT52, but
not with the ANSI terminal, you should change the constant ansi0 to "false" and
vt520 to "true". If you have instead a terminal which is compatible with IBM
PC graphics, you should set the constant "ibmpc0" to "true" and the others to
"false". If your terminal is compatible with none of these, you will have to
set the constants all "false", in which case special graphics characters will
not be used to indicate nucleotide states, but only letters will be used for
the four nucleotides. This is less easy to look at.
The program was written for me by Andrew Keeffe, using some code from
Below is a test tree file, but we cannot show the output it generates
because of the interactive nature of the program.
TEST INPUT TREE FILE
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Maintained 15 Jul 1996 -- by Martin Hilbers(e-mail:M.P.Hilbers@dl.ac.uk)