The relevance of gene transfer to the safety of food and feed derived from genetically modified ( GM ) plants

In 2000, the thematic network ENTRANSFOOD was launched to assess four different topics that are all related to the testing or assessment of food containing or produced from genetically modified organisms (GMOs). Each of the topics was linked to a European Commission (EC)-funded large shared cost action (see http://www.entransfood.com). Since the exchange of genetic information through horizontal (lateral) gene transfer (HGT) might play a more important role, in quantity and quality, than hitherto imagined, a working group dealing with HGT in the context of food and feed safety was established. This working group was linked to the GMOBILITY project (GMOBILITY, 2003) and the results of the deliberations are laid down in this review paper. HGT is reviewed in relation to the potential risks of consuming food or feed derived from transgenic crops. First, the mechanisms 0278-6915/$ see front matter # 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.fct. 2004.02. 001 Food and Chemical Toxicology 42 (2004) 1127–1156 www.elsevier. com/locate/foodchemtox Abbreviations: A. calcoaceticus, Acinetobacter calcoaceticus; A. rhizogenes, Agrobacterium rhizogenes; A. tumefaciens, Agrobacterium tumefaciens; APH, aminoglycoside-30-phosphotransferase; aw, water activity; B. subtilis, Bacillus subtilis; BAC, bacterial artificial chromosome; BMV, brome mosaic virus; C, cytosine; C and N, carbon and nitrogen; C. jejuni, Campylobacter jejuni; CaMV, cauliflower mosaic virus; DNA, deoxyribonucleic acid; DNase, deoxyribonuclease; DPAD, electric discharge particle acceleration device; dsDNA, double-stranded DNA; E. coli, Escherichia coli; E. faecium, Enterococcus faecium; E. faecalis, Enterococcus faecalis; EC, European Commission; ENTRANSFOOD, European network on the safety assessment of genetically modified food crops; EU, European Union; G, guanine; GI, gastrointestinal; GM, genetically modified; GMO, genetically modified organism; GMOBILITY, EU-project on safety evaluation of horizontal gene transfer from genetically modified organisms to the microflora of the food chain and human gut; GURT, Genetic Use Restriction Technology; HFA, human flora associated; HGT, horizontal gene transfer; Kan, kanamycin resistance; L. curvatus, Lactobacillus curvatus; L. delbrueckii subps. bulgaricus, Lactobacillus delbrueckii subps. bulgaricus; L. lactis, Lactococcus lactis; L. monocytogenes, Listeria monocytogenes; mRNA, messenger RNA; mtDNA, mitochondrial DNA; nDNA, nuclear DNA; NLS, nuclear location signal; P. stutzeri, Pseudomonas stutzeri; PCR, polymerase chain reaction; PEG, polyethylene glycol; ptDNA, plastid DNA; rDNA, ribosomal DNA; RE, restriction endonucleases; Ri, root inducing; RNA, ribonucleic acid; rRNA, recombinant RNA; S. gordonii, Streptococcus gordonii; S. pneumoniae, Streptococcus pneumoniae; S. thermophilus, Streptococcus thermophilus; SAAT, sonicationassisted Agrobacterium-mediated transformation; SCP, Scientific Committee on Plants; ss DNA, single-stranded DNA; T-DNA, transfer DNA; TGMV, tomato golden mosaic virus; Ti, tumour inducing; tRNA, transfer RNA; WDV, wheat dwarf virus; YAC, yeast artificial chromosome; ZYMV, zucchini yellow mosaic virus. * Corresponding author. Tel. : +39-3327-85239; fax: +39-3327-85483. E-mail address: guy.van-den-eede@cec.eu. int (G. Eede). for obtaining transgenic crops are described. Next, HGT mechanisms and its possible evolutionary role are described. The use of marker genes is presented in detail as a special case for genes that may pose a risk. Furthermore, the exposure to GMOs and in particular to genetically modified (GM) deoxyribonucleic acid (DNA) is discussed as part of the total risk assessment. The review finishes off with a number of conclusions related to GM food and feed safety. The aim of this paper is to provide a comprehensive overview to assist risk assessors as well as regulators and the general public in understanding the safety issues related to these mechanisms. # 2004 Elsevier Ltd. All rights reserved.