X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=help%2Fhtml%2Fcalculations%2Ftree.html;h=95904b6a18aa960e46a1c430fbe063c3ff7764bf;hb=80ac7d84002118186a11658f38abfa5c4fe3d8da;hp=e9a09085574336e1082922dbbdc7595741e6f96a;hpb=1693646e78fb0dddebcd94f8bef7e2acd3bdaae0;p=jalview.git diff --git a/help/html/calculations/tree.html b/help/html/calculations/tree.html index e9a0908..95904b6 100755 --- a/help/html/calculations/tree.html +++ b/help/html/calculations/tree.html @@ -1,28 +1,130 @@ - - -
-UPGMA tree
-If this option is selected then all sequences are used to generate a UPGMA
- tree. The pairwise distances used to cluster the sequences are the percentage
- mismatch between two sequences. For a reliable phylogenetic tree I recommend
- other programs (phylowin, phylip) should be used as they have the speed to use
- better distance methods and bootstrapping. Again, plans are afoot for a server
- to do this and to be able to read in tree files generated by other programs.
-
- When the tree has been calculated a new window is displayed showing the tree
- with labels on the leaves showing the sequence ids. The user can select the
- ids with the mouse and the selected sequences will also be selected in the alignment
- window and the PCA window if that analysis has been calculated.
Selecting the 'show distances' checkbox will put branch lengths on the branches. - These branch lengths are the percentage mismatch between two nodes.
--
Neighbour Joining tree
- The distances between sequences for this tree are generated in the same way
- as for the UPGMA tree. The method of clustering is the neighbour joining method
- which doesn't just pick the two closest leaves to cluster together but compensates
- for long edges by subtracting from the distances the average distance from each
- leaf to all the others.
- Selection and output options are the same as for the UPGMA tree.
-
+ Calculation of trees from alignments +
++ Trees are calculated on either the complete alignment, or just the + currently selected group of sequences, via the calculations dialog opened from the Calculate→Calculate + Tree or PCA... menu entry. Once calculated, trees are displayed in a new tree viewing + window. There are four different calculations, using one of two + distance measures and constructing the tree from one of two + algorithms : +
++ Distance Measures +
+Trees are calculated on the basis of a measure of similarity + between each pair of sequences in the alignment : +
+ Tree Construction Methods +
+Jalview currently supports two kinds of agglomerative + clustering methods. These are not intended to substitute for + rigorous phylogenetic tree construction, and may fail on very large + alignments. +
+ A newly calculated tree will be displayed in a new tree viewing + window. In addition, a new entry with the same tree viewer window + name will be added in the Sort menu so that the alignment can be + reordered to reflect the ordering of the leafs of the tree. If the + tree was calculated on a selected region of the alignment, then the + title of the tree view will reflect this. +
+ ++ External Sources for Phylogenetic Trees +
++ A number of programs exist for the reliable construction of + phylogenetic trees, which can cope with large numbers of sequences, + use better distance methods and can perform bootstrapping. Jalview + can read Newick + format tree files using the 'Load Associated Tree' entry of the + alignment's File menu. Sequences in the alignment will be + automatically associated to nodes in the tree, by matching Sequence + IDs to the tree's leaf names. +
+ + + +