We just learned that epigenetic mutations occur much more rapidly than DNA mutations, in a study of methylation changes in Arabidopsis. And now it turns out that such epigenetic changes don’t actually last all that long – also from a study of methylation in Arabidopsis. The thing is that a methylation event can occur much more easily than a change in DNA base sequences – and the event is also much more easily undone. The implication is that epigenetics probably isn’t so important for long-term evolution after all.
Scientists at the Max Planck Institute of Developmental Biology in Germany have now produced the first comprehensive inventory of spontaneous epigenetic changes. Using Arabidopsis, the workhorse of modern plant genetics, the researchers determined how often and where in the genome epigenetic modifications occur – and how often they disappear again. They found that epigenetic changes are many orders of magnitude more frequent than conventional DNA mutations, but also often short lived. They are therefore probably much less important for long-term evolution than previously thought.