Risks from GMOs due to Horizontal Gene Transfer

Abstract

Horizontal gene transfer (HGT) is the stable transfer of genetic material from one organism to another without reproduction or human intervention. Transfer occurs by the passage of donor genetic material across cellular boundaries, followed by heritable incorporation to the genome of the recipient organism. In addition to conjugation, transformation and transduction, other diverse mechanisms of DNA and RNA uptake occur in nature. The genome of almost every organism reveals the footprint of many ancient HGT events. Most commonly, HGT involves the transmission of genes on viruses or mobile genetic elements. HGT first became an issue of public concern in the 1970s through the natural spread of antibiotic resistance genes amongst pathogenic bacteria, and more recently with commercial production of genetically modified (GM) crops. However, the frequency of HGT from plants to other eukaryotes or prokaryotes is extremely low. The frequency of HGT to viruses is potentially greater, but is restricted by stringent selection pressures. In most cases the occurrence of HGT from GM crops to other organisms is expected to be lower than background rates. Therefore, HGT from GM plants poses negligible risks to human health or the environment.

Do genetically modified crops affect animal reproduction? A review of the ongoing debate

“…Although the frequencies at which viruses infect a GM plant and recombine with a viral transgene is dependent on a wide range of factors (Keese, 2008), the DNA and protein introduced into biotechnology-derived crops are not different from other sources of DNA in the diet (Animal agriculture's future through biotechnology, 2006). However, there is presently no obvious evidence that mammalian or human cells show altered biological properties due to foreign DNA uptake (Royal Society, 2002), we must nevertheless pay close attention to exogenous DNA and HGT in GM plants as they may pose a risk to human and animal health.…”

Applications (EFSA‐GMO‐RX‐MON810) for renewal of authorisation for the continued marketing of (1) existing food and food ingredients produced from genetically modified insect resistant maize MON810; (2) feed consisting of and/or containing maize MON810, including the use of seed for cultivation; and of (3) food and feed additives, and feed materials produced from maize MON810, all under Regulation (EC) No 1829/2003 from Monsanto

“…Based on current scientific knowledge (EFSA, 2004(EFSA, , 2007b(EFSA, , 2009aKeese, 2008), horizontal gene transfer from GM plants to microorganisms under natural conditions is considered extremely unlikely. Since transgenic DNA is a component of many food and feed products derived from maize MON810, microorganisms in the digestive tract of humans and animals (domesticated animals and other animals feeding on fresh and decaying GM plant material) may be exposed to transgenic DNA.…”

Formulação de Problema em Análise de Risco Ambiental de Cultivos Geneticamente Modificados: Workshop no Brasil

“…The likelihood of horizontal transference of a transgene to soil microorganisms is very small, certainly much lower than the chances of a similar transfer among bacteria (Keese 2008). Bt proteins and Bt DNA, as well as other recombinant proteins and their DNA, can be shed into the soil after the crop is harvested and plant tissues are incorporated in the soil.…”