Genetically Modified Organisms (GMOs)

Introduction

  • Agricultural specialists are concerned about our ability to produce enough food for the growing population.
  • Environmentalists are concerned about the overuse of pesticides and herbicides and the long-term effects of these chemicals on the environment and human health.
  • The biotechnology industry believes genetically modified organisms (GMOs), particularly genetically modified (GM) crop plants, can solve both problems.

Artificial Selection in the Genomic Era

  • Farmers have been genetically modifying crops for centuries and crop breeding to encourage specific traits, such as high yield, is still an important part of agriculture today.
  • There’s now the option to place genes for selected traits directly into crop plants.
    • These genes do not have to originate from the same plant species—in fact, they do not have to come from plants at all.
  • One popular class of GM crops has a gene from the soil bacterium Bacillus thuringiensis (Bt) inserted into their genomes.
  • Bt crops produce a protein called delta-endotoxin that is lethal to European corn borers, a common pest on corn plants.
  • Farmers who plant Bt crops don’t have to apply pesticide because the plants produce the toxic protein inside their cells.
  • When the corn borers feed on the genetically modified plant, they die.
  • Other GMOs include those that are herbicide-resistant delayed for fruit ripening, are resistant to fungi or drought, have increased crop yield, or bear improved fruits.

The GMO Controversy

  • Many people argue that there’s a potential to create super-weeds through cross-pollination with herbicide-resistant crops or that super- bugs will evolve that are no longer resistant to the toxins in pest-resistant crops.
  • Many are concerned with potential allergic reactions.
  • Proponents of GM foods argue these crops are actually better for the environment.
    • Fewer toxic chemicals are put into the environment and thus fewer toxic chemicals can harm the environment and human health.
    • They can preserve arable land by reducing stresses on the land, improve the nutritional value of food in developing countries, and allow crops to be grown on previously unfarmable land.
  • How to test foods:
    • Use an antibody-based test such as the enzyme-linked immunosorbent assay (ELISA), which can detect the proteins that are produced specifically by GM crops.
    • The ELISA isn’t useful for testing foods that have been highly processed, because the proteins have most likely been destroyed and different GM foods produce different proteins.
    • Use the polymerase chain reaction (PCR) to look for a DNA sequence common to GM foods.
    • DNA is more resistant than proteins to processing and can be extracted from even highly processed foods.