Transgenic DNA introgressed into traditional maize landraces in Oaxaca, Mexico

  title={Transgenic DNA introgressed into traditional maize landraces in Oaxaca, Mexico},
  author={David Quist and Ignacio H. Chapela},
Concerns have been raised about the potential effects of transgenic introductions on the genetic diversity of crop landraces and wild relatives in areas of crop origin and diversification, as this diversity is considered essential for global food security. Direct effects on non-target species, and the possibility of unintentionally transferring traits of ecological relevance onto landraces and wild relatives have also been sources of concern. The degree of genetic connectivity between… 

Possible effects of (trans)gene flow from crops on the genetic diversity from landraces and wild relatives.

Diversity in improved varieties grown by farmers needs to be monitored, as the introduction of transgenic technologies has led to a consolidation of the seed industry and a reduction in the diversity of the elite crop gene pool.

Contemporary evolution of maize landraces and their wild relatives influenced by gene flow with modern maize varieties

It is shown here that regulations promoting the adoption of modern cultivars can promote rapid changes in the genetic pools of indigenous landraces (LRs) and crop wild relatives (WRs) and should foster monitoring strategies and policies that use and safeguard the genetic diversity of maize and its WRs at their center of origin.

Detecting adventitious transgenic events in a maize center of diversity

This research could not detect, at the 95% probability level, transgenes in farmers' fields in the valley of Barranca, where there were recent claims of authorized transgenic maize grown.

Transgene Flow: Challenges to the On-Farm Conservation of Maize Landraces in the Brazilian Semi-Arid Region

Brazil is one of the largest global producers of genetically modified crops and a center of origin and diversification of relevant species for agriculture and food. Transgenic monocultures occupy

Introgression from modern hybrid varieties into landrace populations of maize (Zea mays ssp. mays L.) in central Italy

The results show that the maize landraces collected in the last 5–10 years have evolved directly from the flint landrace gene pool cultivated in central Italy before the introduction of modern hybrids, suggesting that coexistence between different types of agriculture is possible.

Transgenes in Mexican maize: molecular evidence and methodological considerations for GMO detection in landrace populations

Analytical and sampling considerations help explain discrepancies among different detection efforts, and provide considerations for the establishment of monitoring protocols to detect the presence of transgenes among structured populations of landraces, suggest the persistence or re‐introduction of transGenes up until 2004 in this area.

Absence of detectable transgenes in local landraces of maize in Oaxaca, Mexico (2003-2004).

It is concluded that transgenic maize seeds were absent or extremely rare in the sampled fields, providing a much-needed preliminary baseline for understanding the biological, socioeconomic, and ethical implications of the inadvertent dispersal of transgenes from the United States and elsewhere to local landraces of maize in Mexico.

Detecting (trans)gene flow to landraces in centers of crop origin: lessons from the case of maize in Mexico.

Using estimates of Ne based on Ortiz-García et al.'s n, it is estimated that transgenes could be present in maize landraces in the Sierra Juárez region at frequencies of approximately 1-4%, and are more likely to bepresent in the 90% of Oaxacan landrace area that is not mountainous.

Ecological risk assessment of genetically modified strawberries - the hybridization potential between cultivated and wild strawberries

It could be shown that clonal reproduction is of great importance for growth and maintenance of F. vesca populations, whereas sexual reproduction seems to be insignificant for population growth within established populations.

New Genes in Traditional Seed Systems: Diffusion, Detectability and Persistence of Transgenes in a Maize Metapopulation

A spatially explicit population genetic model is used to evaluate the importance of seed flow as a determinant of the long-term fate of transgenes in traditional seed systems and finds that in spite of the spatial complexities of the modeled system, persistence probabilities under positive selection are estimated quite well by existing theory.



Gene Flow and Introgression from Domesticated Plants into Their Wild Relatives

A literature review of the world's most important food crops shows that 12 of these crops hybridize with wild relatives in some part of their agricultural distribution, and suggests ways of assessing the likelihood of hybridization, introgression, and the potential for undesirable gene flow from crops into weeds or rare species.

Molecular Evidence for Gene Flow among Zea Species

The available evidence for gene flow between crops and their relatives provides a context for beginning to make realistic assessments of the risk of introgression.

The limits of selection during maize domestication

The results help to explain why maize is such a variable crop, and suggest that maize domestication required hundreds of years, and confirm previous evidence that maize was domesticated from Balsas teosinte of southwestern Mexico.

Transgenic DNA integrated into the oat genome is frequently interspersed by host DNA.

  • W. PawlowskiD. Somers
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1998
It is proposed that transgene integration at multiple clustered DNA replication forks could account for the observed interspersion of transgenic DNA with host genomic DNA within transgenic loci.

Event Specific Transgene Detection in Bt11 Corn by Quantitative PCR at the Integration Site

The integration border was subsequently used to develop a novel and unambiguous PCR detection system covering the integration border at the 5′ site of the transgene, and the genomic sequence showed high similarities with a corn-specific 180 bp knob-associated repeat region.

Of genes and genomes and the origin of maize.

Transgenic pollen harms monarch larvae

In a laboratory assay, it is found that larvae of the monarch butterfly, Danaus plexippus, reared on milkweed leaves dusted with pollen from Bt corn, ate less, grew more slowly and suffered higher mortality than larvae rearing on leaves dusting with untransformed corn pollen or on leaves without pollen.

From Teosinte to Maize: The Catastrophic Sexual Transmutation

Maize, the only cereal with unisexual inflorescences, evolved through a sudden epigenetic sexual transmutation involving condensation of primary branches, which brought their tassels into the zone of female expression, leading to strong apical dominance and a catastrophic shift in nutrient allocation.

A method of detecting recombinant DNAs from four lines of genetically modified maize.

A method using polymerase chain reaction (PCR) was designed for the detection of genetically modified maize, and three insect-resistant GM-maize lines were distinguishable on the basis of the expected lengths of their amplicons.

The earliest archaeological maize (Zea mays L.) from highland Mexico: new accelerator mass spectrometry dates and their implications.

  • D. PipernoK. V. Flannery
  • Medicine, Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 2001
Results suggest that the cultural practices that led to Zea domestication probably occurred elsewhere in Mexico, and Guilá Naquitz Cave has now yielded the earliest macrofossil evidence for the domestication of two major American crop plants, squash and maize.