Fig. 1

Species tree and hypotheses of positive selection on LAEWC trait-shift events. Three positive selection hypotheses are: (a) positive selection independently acted on lineages that gained LAEWC, (b) positive selection independently acted on lineages of lost LAEWC, and (c) positive selection acted on the ancestor of all LAEWC lineages and secondarily acted on the branch of loss LAEWC. The gray area indicates the species with LAEWC. The solid bars and hollow bars indicate the gain events and loss events of LAEWC, respectively. (d) The species tree of the studied Lithocarpus species reconstructed using six LAEWC unrelated genes. Bold branches indicate > 95% posterior probability supporting values for grouping. Species with LAEWC were marked in bold, which revealed non-monophyletic relationship of either LAEWC species or non-LAEWC species. Values near the nodes are the estimated splitting time (Mya) with 95% highest posterior density (gray bars). P and Q at the geological time scale axis are Pliocene and Quaternary, respectively