Small-RNA pathway defends genome against enemy within

For a plant to create reproductive cells, it must first erase a series of tags attached to DNA across the genome that distinguish active and inactive genes. But the marks also keep a host of damaging 'jumping genes' inactive. As the cell wipes away the marks, it activates transposons, which can cause genetic damage. Researchers have discovered a fail-safe mechanism that helps to keep transposons inactive even when these marks are erased.