Fig. 2

The reconciliation \(\mu\) with \(\mu ({{\,\mathrm{lca}\,}}_T(x,y,z))={{\,\mathrm{lca}\,}}_S(X,Y,Z)\) satisfied (R1), (R2), (R3.i), and (R3.ii) but does not admit an unambiguous interpretation of \({{\,\mathrm{lca}\,}}_T(x,y,z)\) as single event: it confounds the speciation separating Z and \({{\,\mathrm{lca}\,}}_S(Y,X)\) with a gene duplication leading the ancestor of x and y or with the speciation separating X and Y. In either interpretation, the reconciliation map \(\mu\) does not correspond to a mechanistic explanation of the gene family history