Guidance on selection of comparators for the risk assessment of genetically modified plants and derived food and feed


Panel on Genetically Modified Organisms
EFSA Journal
EFSA Journal 2011; 9(5):2149
Possible conflict of interest
One member of the Panel did not participate in the discussion on the subject referred to above because of potential conflicts of interest identified in accordance with the EFSA policy on declarations of interests.
Panel members at the time of adoption
Hans Christer Andersson, Salvatore Arpaia, Detlef Bartsch, Josep Casacuberta, Howard Davies, Patrick du Jardin, Gerhard Flachowsky, Lieve Herman, Huw Jones, Sirpa Kärenlampi, Jozsef Kiss, Gijs Kleter, Harry Kuiper, Antoine Messéan, Kaare Magne Nielsen, Joe Perry, Annette Pöting, Jeremy Sweet, Christoph Tebbe, Atte Johannes von Wright, and Jean-Michel Wal

The Panel wishes to thank the members of the Working Group on Selection of Comparators for the Risk assessment of GM plants: Howard Davies, Huw Jones, Gijs Kleter, Harry Kuiper, Antoine Messéan, Joe Perry, Annette Pöting, Pere Puigdomènech and Jean-Michel Wal for the preparatory work on this scientific opinion and, EFSA staff Andrea Germini and Claudia Paoletti for the support provided to this scientific opinion.

Guidance of the Scientific Committee/Scientific Panel
On request from
Question Number
14 April 2011
Published in the EFSA Journal
24 May 2011
Last Updated
9 November 2011. This version replaces the previous one/s.
European Food Safety Authority (EFSA), Parma, Italy

This opinion provides guidance in the area of comparators taking into account the requirements for the molecular characterisation, the food and feed and the environmental risk assessments. A key step in the risk assessment of genetically modified (GM) plants and derived food and feed is the identification of intended and unintended differences and equivalences between the GM plant and its comparator(s), taking into account the range of natural variation. In line with Regulation (EC) No 1829/2003 and Directive 2001/18/EC, the EFSA GMO Panel has, to date, required the use of non-GM lines with comparable genetic background as comparators. In the case of vegetatively propagated crops, these are the isogenic lines. In the case of sexually propagated crops these are non-GM lines as close as possible genetically to the GM plant under assessment. The identification and production of such comparators is becoming increasingly challenging due to the increasing complexity of GM plants, e.g. those developed by combining (stacking) events through conventional crosses, or those in which extensive compositional changes are targeted. Consequently, the EFSA GMO Panel has developed this guidance on the selection of comparators for the risk assessment of GM plants and derived food and feed. Whilst considering the requirements of Directive 2001/18/EC and Regulation (EC) No 1829/2003, the EFSA GMO Panel provides options which introduce flexibility in the selection of comparators based on sound scientific principles. This document addresses the selection of comparators for GM plants containing single or multiple events stacked by either conventional breeding, or by other approaches such as re-transformation, co-transformation and the use of multiple gene cassettes. The EFSA GMO Panel also considers situations where additional comparators may be required on a case-by-case basis and scenarios where appropriate comparators are not available (e.g. where extensive compositional changes are targeted). The EFSA GMO Panel recognises the different requirements for comparators for the molecular characterisation, food and feed and environmental components of the risk assessment.

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