Fig. 1
From: Relative timing information and orthology in evolutionary scenarios
Examples of evolutionary scenarios depicted as gene trees (black inline trees) embedded into species trees (gray outline trees). In all cases, the ancestral gene \({{\,\textrm{lca}\,}}_T(x,y)\) of x and y is highlighted as white circle while the corresponding species \({{\,\textrm{lca}\,}}_S(\sigma (x),\sigma (y))\) is highlighted as dashed line. Top row: scenario with x and y in EDT relation, i.e., the ancestral gene \({{\,\textrm{lca}\,}}_T(x,y)\) diverged concurrently with the corresponding species \({{\,\textrm{lca}\,}}_S(\sigma (x),\sigma (y))\). The evolutionary event at \({{\,\textrm{lca}\,}}_T(x,y)\) is either a speciation (left), a horizontal gene transfer (center), or a duplication (right). Middle row: scenario with x and y in LDT relation, i.e., the ancestral gene \({{\,\textrm{lca}\,}}_T(x,y)\) diverged after the corresponding species \({{\,\textrm{lca}\,}}_S(\sigma (x),\sigma (y))\). The evolutionary event at \({{\,\textrm{lca}\,}}_T(x,y)\) is either a horizontal gene transfer (left), a speciation (center), or a duplication (right). Bottom row: scenario with x and y in PDT relation, i.e., the ancestral gene \({{\,\textrm{lca}\,}}_T(x,y)\) diverged before the corresponding species \({{\,\textrm{lca}\,}}_S(\sigma (x),\sigma (y))\). The evolutionary event at \({{\,\textrm{lca}\,}}_T(x,y)\) is either a duplication (left), a speciation (center), or a horizontal gene transfer (right)