<p>Jalview includes a small number of built in substitution matrices, used for different types of analysis.</p>
<ul>
<li><a href="#blosum62">BLOSUM62</a> is the standard protein sequence alignment and analysis matrix.</li>
-<li><a href="#pam250">PAM250</a> is another standard protein matrix, but not currently available for use from Jalview's user interface.</li>
+<li><a href="#pam250">PAM250</a> is another standard protein matrix, and (since 2.8.1) is available for Tree and PCA calculations.</li>
<li><a href="#simplenucleotide">Simple Nucleotide Substition</a> is a (fairly) arbitrary DNA/RNA substitution matrix.</li>
<!-- <li><a href="#conservation">Conservation Matrices</a> A range of matrices for distinguishing amino-acids by physicochemical property conservation.
</li> -->
<tr><td>Z</td><td>-1</td><td>1</td><td>-3</td><td>1</td><td>4</td><td>-3</td><td>-2</td><td>0</td><td>-3</td><td>1</td><td>-3</td><td>-1</td><td>0</td><td>-1</td><td>3</td><td>0</td><td>0</td><td>-1</td><td>-1</td><td>-2</td><td>-3</td><td>-1</td><td>-2</td><td>4</td></tr>
</table>
<p><strong><a name="pam250">PAM250</a></strong><br/>
+<em><strong>P</strong>ercentage <strong>A</strong>ccepted <strong>M</strong>utation matrix. PAM250 estimates substitutions after 250% of sites have changed (each site can be mutated multple times).<br/>
+Jalview 2.8.1 introduced support for PAM250 based <a href="../calculations/pca.html">PCA</a> and <a href="../calculations/trees.html">tree</a> calculations.</em>
<table border="1">
<tr><td></td><td> A </td><td> B </td><td> C </td><td> D </td><td> E </td><td> F </td><td> G </td><td> H </td><td> I </td><td> K </td><td> L </td><td> M </td><td> N </td><td> P </td><td> Q </td><td> R </td><td> S </td><td> T </td><td> U </td><td> V </td><td> W </td><td> X </td><td> Y </td><td> Z </td></tr>
<tr><td>A</td><td>2</td><td>0</td><td>-2</td><td>0</td><td>0</td><td>-3</td><td>1</td><td>-1</td><td>-1</td><td>-1</td><td>-2</td><td>-1</td><td>0</td><td>1</td><td>0</td><td>-2</td><td>1</td><td>1</td><td>0</td><td>0</td><td>-6</td><td>0</td><td>-3</td><td>0</td></tr>