Do epigenetic mechanisms play a role in evolution and plant improvement?
Heritable alterations of regulatory genes by mutations have certainly played a crucial role during evolution. Their effect, however, to some extent resembles the epigenetic control of gene activities in cell metabolism and in the numerous organism functions during life time. Evolution usually is thought to be based upon preformed random genetic variation, from which the fittest portion is selected by nature. However, epigenetic variation in regulatory systems would seem to be the faster, more effective and more flexible way for a plant to respond as an organism to edaphic or climatic changes in the environment, to temporary abiotic stresses, to competition by other plants, to attack by pathogens and pests, while at the same time maintaining and accurately replicating the accumulated most valuable structural as well as regulatory genes. In contrast to single cell mutations, which become relevant eventually in the next generation, epigenetic alterations almost immediately are expressed i
