Genetically Modified Organisms - Human Triumph or Nemesis? (First of a 2-part Series)

Perhaps you know that GMOs, or genetically modified organisms, refer to a whole class of crops and animals whose genes have been altered by humans. Maybe you didn't know that we've been doing this for millennia. Maybe you didn't know that crops engineered to resist some pest - weeds or insects - aren't the only use of so-called transgenic crops. Maybe you're confused or just plain overwhelmed with all the "expert" information out there, and you're really not sure what to think. Let's start with some basic information, including some resources you can check yourself for more information.

Every living thing on earth except viruses is based on DNA, arranged into chunks of genes. Genes are clumped together in chromosomes, and the entire chunk of genes that make a radish a radish and a mouse a mouse is its genome. GMOs refer to crop plants and animals that have been genetically manipulated by humans. As insidious as that sounds, we've been doing it since the dawn of agriculture 10,000 years ago. All the grain crops, many vegetables and fruits, and most domesticated animals have been bred to encourage certain traits (like large starchy kernels in corn, tomatoes that travel well, or cows that produce milk all the time) and discourage others. Without knowing exactly which gene makes firmer tomatoes or sweeter sweet corn, trial-and-error breeding over millennia makes the desirable gene or genes more common, and the less desirable ones less dominant. Not every kernel of corn will be perfectly sweet, and a few of the thousands of tomatoes will still rot before they're sold, because hybridization sometimes encourages unexpected traits. For better or worse, this genetic manipulation has made possible the human domination of the planet. (More on population, sustainability, clean water, clean air, and ecosystem manipulation some other time.)

Recently, the technology to manipulate small pieces of the genome have become available. Instead of trial-and error manipulation of the genome, it's possible to insert just one gene into a plant that allows the plant to express a trait that's hard to breed into the plant, or that benefits humans or the environment some other way. This is typically called genetic engineering (GE). It's different from the example above because the plant or animal still has all its own genes, plus the one or two from somewhere else added to the plant or animal. Instead of moving the whole genome, GE moves one or two genes. However, the one or two genes may come from another species. Now our questions are, Why do this? How is it done? What are the consequences?

There are two main purposes for transgenic crops today: to increase yields, and for other human benefit. Pests, like insects and weeds, still claim a significant portion of the agricultural yield around the world. Where soils are poor, or environmental conditions more variable, pests claim an even larger proportion of crops and forage. The reasoning behind GE crops is that pest-resistant crops have higher yields, and therefore the ability to feed more people. Fish and animals may be genetically altered to grow faster larger, or to resist some disease by having an antibiotic gene inserted into its genome.

The second purpose for transgenic crops is the more nebulous idea of human benefit. So far, this has meant a strain of rice that's been genetically altered to produce beta carotene, the precursor to vitamin A and an important nutrient in the prevention of blindness. Strains of rice that vaccinate consumers against malaria and cholera are also being tested.

Down the road, GE technology may be used to produce fruit trees resistant to pests, other plant-based vaccine and nutrient delivery, or environmental cleaners like bacteria that can consume toxins and break the toxins into harmless compounds.

Right now, the technology is still young. Plant modifications are performed on the female part of the plant because seeds are larger than pollen grains. Usually, the desired gene is "shot" into the plant gene. The GE seeds are planted, and the next generation produces both pollen and seeds that carry the new gene. For plants pollinated by wind, like canola and corn, pollen from GE plants may fertilize non-GE crops. The procedure is similar in animals and fish such as salmon.

Many medicines are produced by genetic engineering. Since 1982, insulin has been produced by inserting the gene that expresses insulin production into bacteria. Human growth hormone, several antibiotics, and several vaccines are now produced by genetic engineering.

This is the question producing so many of the statements about GE plants and animals, from plausible to outrageous, from genuine concern to hysteria. In the next issue of the newsletter, we'll look at the approval process for GE organisms from development to market, then delve into some of the ethical arguments for and against GE organisms. Finally, we'll take a look at some of the research on already-existing GE crops, such as Bt corn and Roundup(R)-ready soybeans.