Abstract:
Plant genomes vary in size and complexity, fueled in part by processes of whole-genome
duplication (WGD; polyploidy) and subsequent genome evolution. Despite repeated
episodes of WGD throughout the evolutionary history of angiosperms in particular, the
genomes are not uniformly large, and even plants with very small genomes carry the
signatures of ancient duplication events. The processes governing the evolution of plant
genomes following these ancient events are largely unknown. Here, we consider
mechanisms of diploidization, evidence of genome reorganization in recently formed
polyploid species, and macroevolutionary patterns of WGD in plant genomes and propose
that the ongoing genomic changes observed in recent polyploids may illustrate the
diploidization processes that result in ancient signatures of WGD over geological
timescales.
