* PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with Jalview. If not, see <http://www.gnu.org/licenses/>.
---!>
-<head><title>Tree Calculation</title></head>
-<body>
-<p><strong>Calculation of trees from alignments</strong></p>
-<p>Trees are calculated on either the complete alignment, or just the
-currently selected group of sequences, using the functions in the
-<strong>Calculate→Calculate tree</strong> submenu.
-Once calculated, trees are displayed in a new <a
-href="../calculations/treeviewer.html">tree viewing window</a>. There are
-four different calculations, using one of two distance measures and
-constructing the tree from one of two algorithms :
-</p>
-<p><strong>Distance Measures</strong></p>
-<p>Trees are calculated on the basis of a measure of similarity
-between each pair of sequences in the alignment :
-<ul>
-<li><strong>PID</strong><br>The percentage identity between the two
-sequences at each aligned position.<ul><li>PID = Number of equivalent
-aligned non-gap symbols * 100 / Smallest number of non-gap positions
-in either of both sequences<br><em>This is essentially the 'number of
-identical bases (or residues) per 100 base pairs (or residues)'.</em></li></ul>
-<li><strong>BLOSUM62</strong><br>The sum of BLOSUM62 scores for the
-residue pair at each aligned position.
-</ul>
-</p>
-<p><strong>Tree Construction Methods</strong></p>
-<p>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.
-<ul>
-<li><strong>UPGMA tree</strong><br>
- UPGMA stands for Unweighted Pair-Group Method using Arithmetic
- averages. Clusters are iteratively formed and extended by finding a
- non-member sequence with the lowest average dissimilarity over the
- cluster members.
-<p></p>
-</li>
-<li><strong>Neighbour Joining tree</strong><br>
- First described in 1987 by Saitou and Nei, this method applies a
- greedy algorithm to find the tree with the shortest branch
- lengths.<br>
- This method, as implemented in Jalview, is considerably more
- expensive than UPGMA.
-</li>
-</ul>
-</p>
-<p>A newly calculated tree will be displayed in a new <a
-href="../calculations/treeviewer.html">tree viewing window</a>. 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.</p>
-
-<p><strong>External Sources for Phylogenetic Trees</strong></p>
- <p>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 <a
- href="http://evolution.genetics.washington.edu/phylip/newick_doc.html">Newick</a>
- 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.
- </p>
-
-
-</body>
-</html>
+-->
git://source.jalview.org / jalview.git / blobdiff