Samples of rice from Mexican and USA retail stores were analyzed for the presence of transgenic (GM) events using real-time PCR. In screening for the
CaMV35S
promoter sequence (
35SP
), positive ...results were found in 49 and 35% of the Mexican and American samples, respectively. In further investigations in Mexican samples, 43% were positive for
P35S::bar
, with two above the quantifiable limit; these were 0.07% and 0.05% GMO. Fourteen out of the sixteen positive samples were labeled as imported from the USA. In testing samples bought in American retail shops, 24% showed positive results, all below the quantifiable range. It could be deduced that
P35S::bar
positive samples were Liberty Link® (LL) rice. In distinguishing between LL601 and LL62, end-point PCR was used, corroborating the
P35S::bar
amplicon length difference of these events. LL62 was found in one rice sample purchased in Mexico and two in the USA samples. Its presence was verified with the 35S terminator sequence. All other LL positive samples contained LL601. None of the samples analyzed showed the presence of Bt63 rice. The LL rice varieties found have been identified as not being commercially cultivated, and so their presence requires further investigation.
35SP
was also present in samples which did not have any LL rice. Maize sequences could not be detected in any of the samples; however, soybean DNA was found in Mexican and USA rice samples. The Roundup Ready® trait was detected in trace amounts in 16 and 6% of the rice samples bought in Mexico and the USA, respectively. Real-time PCR was shown to be the method of choice for the sensitive and rapid screening of commodities and retail samples for the detection of GM and other contamination.
Safflower (Carthamus tinctorius L.) is currently being developed as a platform for the production of novel proteins. Methods for detecting and quantifying transgenic safflower are needed to ensure ...seed quality and to monitor for its adventitious presence. We developed and compared three methods of assaying for transgenic safflower presence in conventional seedlots: field bioassays, enzyme-linked immunosorbent assays (ELISA), and quantitative polymerase chain reaction (Q-PCR). Limits for reliable quantification for both ELISA and Q-PCR are ∼0.1%, although levels at least as low as 0.02% can be detected by Q-PCR. Levels of quantification for the field bioassay are limited only by space and resources available. Multiple sampling methods to detect and quantify transgenic safflower presence at levels lower than 0.1% were used on field collected samples from a pollen outcrossing experiment to quantify the adventitious presence of transgenic safflower. Taking into account the potential utility and relative advantages or disadvantages of each detection method, it is recommended that the initial testing for the adventitious presence of transgenic seed be carried out using an antibody-based test if available and that Q-PCR-based assays to quantify transgenic proportion be used when it is necessary to identify specific transgenic constructs or if antibody-based assays are not readily available.
When detecting the adventitious presence of transgenic plants (AP), it is important to use an appropriate testing method in the laboratory. Dorfman's group testing method is effective for reducing ...the number of laboratory analyses, but does not consider the case where AP is diluted below the sensitivity of the analyses, which causes the rate of false negatives to increase. The objective of this study is to propose binomial and negative binomial probabilistic models for determining the required sample size (n), number of pools (g), and size of the pool (k) for detecting individuals possessing AP with a probability ≥ (1 − α) (for a small α) given: (1) pool size (k); (2) estimated proportion of individuals with AP in the population (p); (3) concentration of the trait of interest (AP) in individual seeds (w); and (4) detection limit of the test (c) (AP concentration in a pool below which it cannot be detected). The proposed models consider the different rates of false positives (δ) and false negatives (λ), and the assessment of consumer and producer risks. Results have shown that when using the negative binomial, a required sample size n can be determined that guarantees a high probability that m individuals or g pools containing AP will be found. The pools formed have an optimum size, such that one element with AP will be detected at a low cost. The negative binomial distribution should be used when it is known that the proportion of individuals with AP in the population is p < 0.1; thus, it is guaranteed that m individuals or g pools of individuals with AP will be detected with high probability.
When the laboratory methods employed are qualitative, the statistical methodologies used in testing for the adventitious presence (AP) of transgenic material in conventional seed and grain lots are ...well defined. However, when the response from the method used by the laboratory is quantitative (e.g. percent transgenic DNA), the statistical methodologies developed for qualitative laboratory methods are not fully appropriate. In this paper, we present the details of procedures specific to quantitative laboratory methods. In particular we consider: (1) the assessment of quantitative laboratory method errors using linear modelling; and (2) the process of deciding whether or not a lot meets pre-specified purity standards, including the development of probability calculations needed to develop operating characteristic curves and estimate consumer and producer risks for a given lower quality limit (LQL), acceptable quality limit (AQL) and testing plan. We also describe implementation of this approach in a useful spreadsheet application.
Overall, the deregulation of genetically engineered (GE) crops for commercial cultivation in North America has been a success story. In several cases, however, GE crops have sparked concerns and ...disagreements among the stakeholders and there are incidences of court lawsuits, including a recent one on glyphosate resistant (GR) alfalfa (
Medicago sativa
, L.). While GE crops can provide operational benefits to farmers, challenges are looming from commercialization of perennial GE crops. The unique ecology and biology of these crops and GE alfalfa in particular can facilitate adventitious presence (AP) of GE traits and it makes more visible that economic risks for conventional growers and food/feed producers have not been adequately addressed by the GE regulatory system in the United States (US). Asynchronous market approvals and the existence of a number of GE sensitive export markets create uncertainties among the exporters. Policy development in these fields may be helpful for ensuring a broader acceptance and market success of GE agriculture in general. The analysis is focusing on the US, although many diagnosed problems are also relevant to other jurisdictions—in particular if no co-existence policy is in place.
The myriad of litigation and class action suits surrounding Syngenta’s Viptera corn covers many issues that have been well addressed in previous litigation and literature. However, the case of ...Syngenta v Bunge raised the fascinating issue of ‘regulatory lag’, i.e., a situation where there are significant delays in approval of a GM product in an emerging export market, or differences in the regulatory approval timetable between significant export markets. In this case, Syngenta argued that Bunge’s blanket refusal to accept Viptera corn into its facilities because China had not yet approved the variety, even though the variety was approved in the United States and in many other larger export markets, amounted to illegal activity that would cause significant harm to Syngenta. Although the litigation was ultimately settled in December 2014 by a confidential agreement between the parties, the case raises significant issues for the technology developers, producers, handlers, processers and shippers in instances where ‘regulatory lag’ is occurring or is possible. This article examines the legal implications of these lags for these parties, including an examination of their potential legal obligations and liabilities.
La perspective de la culture de variétés transgéniques pose, pour de multiples raisons, le problème de la ségrégation de filières de production basées sur la même espèce dans les paysages agricoles : ...demande d'une filière « sans OGM » ; coexistence de productions alimentaires et non alimentaires… La réglementation européenne fixe un seuil de présence fortuite d'OGM au-delà duquel un produit, même issu d'une variété non-OGM, doit être étiqueté comme contenant des OGM. La Commission européenne a émis des recommandations sur l'adoption de pratiques favorisant la coexistence entre cultures OGM et non-OGM de façon à ce que les agriculteurs puissent garder la liberté de choisir le mode de production qu'ils souhaitent. Dans ce contexte, il est important de pouvoir estimer a priori le taux d'impuretés OGM dans les récoltes de parcelles non-OGM, en fonction de leur organisation spatiale et du climat, mais aussi de comprendre et prédire l'effet de modifications de pratiques agricoles sur ce taux. L'expérimentation peut apporter des éléments de connaissances des phénomènes, la modélisation s'avère cependant plus pertinente pour répondre aux demandes d'aide à la décision (principalement publique) pour des situations agricoles et climatiques diversifiées. L'objectif de la thèse est donc de dégager un cadre méthodologique générique pour le développement de modèles de flux biologiques combinant de façon dynamique modélisation, évaluation et expérimentation. Le travail de thèse a consisté en la conception et l'évaluation du modèle MAPOD qui simule les flux de gènes chez le maïs à l'échelle du paysage. Ce modèle est basé sur une fonction de dispersion individuelle qui dépend de paramètres biologiques et climatiques et qui calcule une probabilité de fécondation en un point (x, y) en fonction de la distance à la source émettrice de pollen (pollinisation efficace). Il comporte un module de dynamique de floraison qui rend compte des conséquences des synchronismes ou asynchronismes de floraison entre champs sur les taux d'OGM dans les récoltes. Le modèle permet de déterminer l'effet de la distribution spatiale des parcelles de maïs, des caractéristiques variétales, du climat et des itinéraires techniques sur les taux de pollinisation croisée. MAPOD a été mis au point à partir de données de la littérature et d'expérimentations menées par le GEVES. Cette première version a été évaluée grâce à un second jeu de données provenant du GEVES. Elle a aussi fait l'objet d'une analyse de sensibilité. Les résultats obtenus ont permis de définir les pistes d'amélioration de l'algorithme. La qualité prédictive de MAPOD a ensuite été estimée grâce à des données issues de suivis effectués pendant 5 ans dans des parcelles d'agriculteurs en Catalogne, région où le maïs Bt est cultivé à grande échelle. La pertinence des décisions prises grâce aux sorties du modèle a aussi été caractérisée. MAPOD a été utilisé pour simuler différents scénarios d'introduction de variétés OGM dans les systèmes de culture européens. L'efficacité de mesures individuelles de coexistence a été testée. Ensuite, c'est l'effet de combinaison de pratiques qui a été simulé, aboutissant à l'établissement de tables de décision en fonction du contexte de culture. À l'échelle du bassin de collecte, l'efficience des stratégies de ségrégation (spatiale, temporelle) pouvant être mises en place par les organismes de collecte-stockage a aussi été étudiée grâce au modèle. Enfin, les sorties de MAPOD ont servi comme support pour la mise au point d'un outil d'aide à la décision à destination des agriculteurs et de leurs conseillers.
Consumer demand for food free of GMOs is growing and if production standards are to be met, food and non-food chains must be separated. Indeed, European Commission regulations 1829/2003 and 1830/2003 stipulate that food and feed thought to be GMO-free but found to be containing more than a 0.9% portion of an adventitious presence of authorized GMOs have to be distinguished, traced and labelled as such. Moreover, to ensure that producers have a choice a choice among differing types of production, the European Commission has issued recommendations that permit the coexistence of non-GM and GM crops. This poses the problem of how to deal with coexistence in an agricultural supply chain dedicated to handling a single crop species. To help in the elaboration of coexistence rules, and then assess their feasibility and their consequences as well as for setting up monitoring and control schemes, specific field experiments, even if necessary, are not sufficient as their predictive value remains restricted to a given context. It is necessary to be able to forecast the fate of GM crops at the landscape level taking into account the various cropping systems and agricultural practices that may occur across Europe. The key to forecasting spread and behaviour of GM plants and seeds as well as their impacts under a wide range of agro-ecosystems is modelling. Models reproduce the functioning of agro-systems and take into account the relevant factors and processes as well as their interactions. They thus make it possible to simulate the behaviour of agro-systems in non-observed situations and on a long term basis.This doctoral thesis establishes a methodological framework for the development of biological flow models thanks to the dynamic interactions of modelling, evaluation and experimentation. In a first phase, the work involved the design of the MAPOD® model developed in relationship to literature and varietal experiments carried out by GEVES. MAPOD® simulates gene flow between maize crops at the landscape scale. It is based on an individual dispersal function which depends on biological and climatic parameters. It calculates the probability of fecundation at a (x, y) point as a function of distance from the pollen emitter (efficient pollination). Its flowering dynamics module makes it possible to take into account of the consequences of flowering time - lags on GM adventitious presence in harvests. MAPOD® evaluates the effect of the spatial distribution of maize plots, varietal characteristics, and climate as well as agricultural practices on cross-pollination. In this investigation, in a second phase the initial version of MAPOD® was evaluated with another dataset provided by GEVES. Ways to improve the algorithm were thereby defined. In a third phase, the predictive quality of MAPOD® was estimated by comparing model outputs to cross-pollination rates which were obtained by monitoring farmers' fields in Catalonia (Spain) over a 5-year period. The relevance of decisions made according to model output was also evaluated.In a fourth phase, MAPOD® was used to simulate different scenarios involving the introduction of GM varieties into European cropping systems. The efficiency of individual coexistence measures was tested. Afterwards, the effect of combining different types of practices was simulated, leading to a set of decision-support tables elaborated according to the cropping context. At the scale of the collecting basin, with the enhanced version of MAPOD®, the efficiency of segregation strategies (spatial or temporal) that could be implemented by collecting and storing organisations was also studied. Lastly, model outputs were used as a basis for the design of a decision-support tool for use by farmers and extension workers.
This article explores consumers perceptions and attitude toward genetically modified(GM) foods by looking at the level of concerns over those foods and willingess to pay for GM corn oil, manufactured ...from corn with strenthening thresholds for adventitious presence(AP). A survey shows that the most important information for GM foods consumers need is a safety. Consumers requires an enhanced safety review about safety assessment to solve their anxiety about GM foods before are more likely to pay more. As consumers consider a country-of-origin as an important factor when buying foods, probability of paying more for corn oil with intensifying thresholdss is higher.
