Gene activities can be regulated by epigenetic modifications of nucleotides and chromatin that are stably propagated through somatic cell divisions and, in some cases, across generations. The mechanisms that control epigenetic marks have recently been uncovered using model organisms, such as the flowering plant Arabidopsis thaliana VSports手机版. In Arabidopsis, perturbation of epigenetic gene activity often results in heritable developmental phenotypes. Stable, but potentially reversible, changes in epigenetic status can also be sources for phenotypic variations in natural plant populations. .