Regulatory framework of genome editing in Brazil and worldwide.

The regulation of the use of products obtained through genome-editing techniques has been the subject of great debate worldwide. Currently, the discussions are mainly focused on whether products obtained by different strategies of site-directed nucleases (SDN) should or not be classified as Genetically Modified Organisms (GMOs). In the SDN-1 application, the natural DNA cell repair pathway (Non-Homologous End-Joining - NHEJ) is explored to introduce simple random mutations (substitutions, insertions, and deletions) by systems such as CRISPR-Cas, TALENs, or Zinc Fingers Nucleases, which cause silencing of the gene product after breaking DNA (by Double-Strand Break - DSB). In the SDN-2 approach, a template DNA is also used to introduce a change in the sequence of nitrogen bases (A, C, G, T) at the target site where the DSB occurred, exploring another natural repair system directed by a DNA fragment from the same species (Homology-Directed Repair - HDR). In the SDN-3 approach, both NHEJ and HDR can be explored to insert one or more DNA fragments with sequences necessary for the expression of a gene (promoter, coding, and terminator region) at a specific location in the genome. In the following topics, questions related to genome editing regulation in different countries are discussed in detail.