-------</span>
<span class="sd">    pandas.DataFrame</span>
<span class="sd">        Mapping table containing assignment of</span>

<span class="sd">        1. index in target sequence (i)</span>
<span class="sd">        2. symbol in target sequence (A_i)</span>

<span class="sd">        For all other sequences in alignment, the following</span>
<span class="sd">        two columns:</span>

<span class="sd">        3. index in second sequence (j_&lt;sequence id&gt;)</span>
<span class="sd">        4. symbol