Maize x Teosinte Hybrid Cobs Do Not Prevent Crop Gene Introgression

Maize x Teosinte Hybrid Cobs Do Not Prevent Crop Gene Introgression. Whether introgression from crops to wild relatives can occur is an important component of transgene risk assessment. In the case of maize, which co-occurs with its wild relative teosinte in Mexico, the possibility of introgression has been controversial. Maize is cross-compatible with teosinte, and spontaneous hybridization is known to occur. Some scientists have hypothesized that the maize x teosinte cob infructescence will prevent progeny dispersal, thus preventing introgression. Motivated by a prior study where we found maize x teosinte hybrid fruits naturally dispersed under field conditions, we tested whether hybrid cobs hold their fruits as tightly as maize cobs. We found the force required to detach hybrid fruits was substantially and significantly less than that for maize. Consequently, we expect that introgression of transgenes from maize into teosinte in Mexico should occur largely unimpeded by the hybrid cob.La mazorca o elote híbrido de maíz x teocintle no impide la introgresión de genes transgénicos provenientes del cultivo. La introgresión entre el maíz cultivado y el maíz silvestre, o teocintle, es un componente importante en la evaluación ambiental relacionada con los riesgos de la introducción de genes transgénicos. La posibilidad de introgresión entre el maíz domesticado y el teocintle ha sido un tema controversial, en particular en México, donde maíz y teocintle coexisten. El maíz es compatible con el teocintle y la hibridización espontánea ocurre entre ellos. Algunos científicos han planteado como hipótesis que al cruzar el maíz con teocintle, la estructura interna de la infrutescencia que sujeta los frutos conocida como la mazorca de maíz o el elote, impide la dispersión de la progenie evitando que la introgresión ocurra. Los resultados de un estudio previo evidencian la dispersión de los frutos híbridos del maíz x teocintle en condiciones naturales. Motivados por estos resultados, hemos decidido investigar si la mazorca o el elote de las infrutescencias del híbrido sujetan los frutos con una fuerza comparable o mayor a la del maíz. Nuestras mediciones implican que la fuerza necesaria para liberar los frutos híbridos son substancial y significativamente menores que aquellas necesarias para desprender los frutos del maíz. Como conclusión sugerimos que en México, la mazorca o el elote no representan una barrera que impida la introgresión de los genes transgénicos del maíz al teocintle

EFSA BIOHAZ Panel (EFSA Panel on Biological Hazards), 2013. Scientific Opinion on the public health hazards to be covered by inspection of meat (bovine animals).

A risk ranking process identified Salmonella spp. and pathogenic verocytotoxin-producing Escherichia coli (VTEC) as current high-priority biological hazards for meat inspection of bovine animals. As these hazards are not detected by traditional meat inspection, a meat safety assurance system for the farm-to-chilled carcass continuum using a risk-based approach was proposed. Key elements of the system are risk-categorisation of slaughter animals for high-priority biological hazards based on improved food chain information, as well as risk-categorisation of slaughterhouses according to their capability to control those hazards. Omission of palpation and incision during post-mortem inspection for animals subjected to routine slaughter may decrease spreading and cross-contamination with the high-priority biological hazards. For chemical hazards, dioxins and dioxin-like polychlorinated biphenyls were ranked as being of high potential concern; all other substances were ranked as of medium or lower concern. Monitoring programmes for chemical hazards should be more flexible and based on the risk of occurrence, taking into account the completeness and quality of the food chain information supplied and the ranking of chemical substances, which should be regularly updated to include new hazards. Control programmes across the food chain, national residue control programmes, feed control and monitoring of environmental contaminants should be better integrated. Meat inspection is a valuable tool for surveillance and monitoring of animal health and welfare conditions. Omission of palpation and incision would reduce detection effectiveness for bovine tuberculosis and would have a negative impact on the overall surveillance system especially in officially tuberculosis free countries. The detection effectiveness for bovine cysticercosis, already low with the current meat inspection system, would result in a further decrease, if palpation and incision are removed. Extended use of food chain information could compensate for some, but not all, the information on animal health and welfare lost if only visual post-mortem inspection is applied