a A schematic representation of a non-autonomous trans-acting gene drive. A Cas9 unit and a gRNA unit are placed in a location far away from the target gene (on a different chromosome). The Cas9/gRNA complex cuts the wild type allele of the target gene. Subsequently, the DSB is repaired using the DNA from the homologous chromosome as the template, resulting in a homozygous plant. b The NPY5-GFP line can be used to test a non-autonomous trans-acting gene drive in Arabidopsis. The line contains an EC-Cas9 unit and a gRNA unit on Chromosome II while the target wild type NPY5 is on Chromosome IV. The NPY5 gene has been tagged with GFP. The DD45-Cas9 unit on Chromosome V may provide additional Cas9 for the non-autonomous trans-acting gene drive. c The functionality of the non-autonomous trans-acting gene drive was tested by crossing the NPY5-GFP line to wild type Ler. Cas9/gRNA from Chromosome II cuts wild type NPY5, generating a DSB. The GFP and DNA flanking GFP is used as a template for HDR, resulting in homozygous NPY5-GFP F1 plants.