Polyploidization and epigenetics

The occurrence of polyploidy, or whole genome duplication, can result in instantaneous speciation. Because new polyploids are immediately reproductively isolated from their non-polyploid congeners, polyploidization has played an important role in the diversification of flowering plants and some vertebrates. Newly formed polyploids must respond to this instantaneous genomic change, which resembles “genome shock” syndrome to survive and reproduce successfully. Epigenetic changes, which do not cause changes to the sequence of DNA, can significantly contribute to the survival of and ultimately to the evolutionary success of new polyploids. Epigenetic regulation, both transcriptional and post-transcriptional, entails changes in DNA methylation, gene status and/or nucleolus dominance. These changes provide effective and flexible ways for a new polyploid to respond quickly to the enormous change in genetic material, to survive and potentially reproduce. We examine and assess certain epigenetic phenomena and possible pathways that may facilitate the evolutionary success of polyploid organisms.