Kinetochore and ionomic adaptation to whole genome duplication

Whole genome duplication (WGD) brings challenges to key processes like
meiosis but nevertheless is associated with diversification in all
kingdoms. How is WGD tolerated, and what processes commonly evolve to
stabilize the new polyploid lineage? Here we study this in Cochlearia
spp., which have experienced multiple rounds of WGD in the last 300,000
years. We first generate a chromosome-scale genome and sequence 113
individuals from 33 diploid, tetraploid, hexaploid, and outgroup
populations. We detect the clearest post-WGD selection signatures in
functionally interacting kinetochore components and ion transporters. We
structurally model these derived selected alleles, associating them with
known WGD-relevant functional variation, and compare these results to
independent recent post-WGD selection in Arabidopsis arenosa and Cardamine
amara. Some of the same biological processes evolve in all three WGDs, but
specific genes recruited are flexible. This points to a polygenic basis
for modifying systems that control the kinetochore, meiotic crossover
number, DNA repair, ion homeostasis, and cell cycle. Given that DNA
management (especially repair) is the most salient category with the
strongest selection signal, we speculate that the generation rate of
structural genomic variants may be altered by WGD in young polyploids,
contributing to their occasionally spectacular adaptability observed
across kingdoms.