p>Pair-level covariate derived from X1: 1 if match, 0 if not match.</p></dd>

<dt>Z2</dt>
<dd><p>Pair-level covariate derived from X2: 1 if match, 0 if not match.</p></dd>

<dt>Z3</dt>
<dd><p>Pair-level covariate derived from X3: 1 if a-a, 2 if b-b, 3 if a-b, 4 if b-a.</p></dd>

<dt>Z4</dt>
<dd><p>Pair-level covariate derived from X4: 1 if match, 2 if adjacent, 2 otherwise.</p></dd>


</dl></div>
    <div id="references">
    <h2>References</h2>
    <p>Schliep KP. phangorn: Phylogenetic analysis in R. Bioin