Transposable element origins of epigenetic gene regulation

► TEs are abundant, enormously variable and rapidly changing in all plant genomes. ► Epigenetic processes first evolved to silence TEs and viruses. ► TE insertion near a gene can place that gene under TE-derived epigenetic control. ► Stress may awaken zombie TEs in the hetrochromatin that rise up to kill active TEs. ► Gene acquisition and degradation inside TEs may be the ongoing origin of miRNA genes.