Diploidization

Diploidization is the process by which a polyploid genome, one carrying more than the usual two full sets of chromosomes, is converted back into a functionally diploid one. It typically follows a whole genome duplication or a hybridization event, both of which leave a genome unstable and under pressure to restore a normal chromosome number and function. The process unfolds in two phases, an early, rapid phase of genome reorganization that stabilizes the chromosomes, followed by a longer evolutionary phase in which duplicated genes are either lost or take on new functions, driven by the need to restore proper gene dosage, allow stable chromosome pairing during cell division, and reduce the metabolic cost of carrying a large genome. Plants are known to have undergone this process repeatedly over their evolutionary history, and evidence suggests vertebrates have as well. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/