Applicability of the EFSA Opinion on site‐directed nucleases type 3 for the safety assessment of plants developed using site‐directed nucleases type 1 and 2 and oligonucleotide‐directed mutagenesis

site‐directed nuclease, SDN‐1, SDN‐2, SDN‐3, oligonucleotide‐directed mutagenesis, transgenesis, off‐target, genetically modified plants, risk assessment, EFSA guidance
First published in the EFSA Journal
24 Noviembre 2020
14 Octubre 2020
Scientific Opinion


The European Commission requested the EFSA Panel on Genetically Modified Organisms (GMO) to assess whether section 4 (hazard identification) and the conclusions of EFSA's Scientific opinion on the risk assessment of plants developed using zinc finger nuclease type 3 technique (ZFN‐3) and other site‐directed nucleases (SDN) with similar function are valid for plants developed via SDN‐1, SDN‐2 and oligonucleotide‐directed mutagenesis (ODM). In delivering this Opinion, the GMO Panel compared the hazards associated with plants produced via SDN‐1, SDN‐2 and ODM with those associated with plants obtained via both SDN‐3 and conventional breeding. Unlike for SDN‐3 methods, the application of SDN‐1, SDN‐2 and ODM approaches aims to modify genomic sequences in a way which can result in plants not containing any transgene, intragene or cisgene. Consequently, the GMO Panel concludes that those considerations which are specifically related to the presence of a transgene, intragene or cisgene included in section 4 and the conclusions of the Opinion on SDN‐3 are not relevant to plants obtained via SDN‐1, SDN‐2 or ODM as defined in this Opinion. Overall, the GMO Panel did not identify new hazards specifically linked to the genomic modification produced via SDN‐1, SDN‐2 or ODM as compared with both SDN‐3 and conventional breeding. Furthermore, the GMO Panel considers that the existing Guidance for risk assessment of food and feed from genetically modified plants and the Guidance on the environmental risk assessment of genetically modified plants are sufficient but are only partially applicable to plants generated via SDN‐1, SDN‐2 or ODM. Indeed, those guidance documents’ requirements that are linked to the presence of exogenous DNA are not relevant for the risk assessment of plants developed via SDN‐1, SDN‐2 or ODM approaches if the genome of the final product does not contain exogenous DNA.

This publication is linked to the following EFSA Supporting Publications article:

Panel members at the time of adoption

Hanspeter Naegeli, Jean‐Louis Bresson, Tamas Dalmay, Ian Crawford Dewhurst, Michelle M Epstein, Leslie George Firbank, Philippe Guerche, Jan Hejatko, Francisco Javier Moreno, Ewen Mullins, Fabien Nogué, Nils Rostoks, Jose Juan Sánchez Serrano, Giovanni Savoini, Eve Veromann and Fabio Veronesi.
Panel on Genetically Modified Organisms
GMO_secretariat_applications [at]
EFSA Journal 2020;18(11):6299
Question Number
On request from
European Commission