Adaptation to autopolyploidy in Cardamine amara. Adaptation to autopolyploidy in Cardamine amara

Whole genome duplication (WGD) can promote adaptation but is traumatic to conserved processes. Work in Arabidopsis arenosa revealed a coordinated evolutionary response to WGD, involving physically interacting proteins mediating meiotic crossovers. Here we test whether this striking evolutionary response is constrained by resequencing and cytologically assessing replicated populations from the diploid/autotetraploid system, Cardamine amara. We find that gene-level convergence is negligible, but convergence is obvious in functional processes, including meiotic cell cycle, chromosome organisation and stress signalling. This gives the first genomic insight into the salient adaptations required to meet the challenges of WGD and shows that autopolyploids can utilize multiple trajectories to adapt to WGD.