Corn, also known as maize, began life as a lean grasslands plant called teosinte about 10,000 years ago. In the span of time since, teosinte plants were bred with each other and other plants to produce the corn plant we know today. As human consumption and demand for cereal crops changes, the need for different plants arises. Strictly speaking, modified maize refers to any corn that is altered with human intervention to produce a more desirable product. The term typically refers to corn that is genetically altered to be resistant to environmental limitations or threats, pests and disease.
Like all living things, corn contains organic markers called genes. Genes control the characteristics of the plant — whether it is resistant to pesticides, how big it gets, how hardy it is and whether or not it can defend itself against predators. Genetically modified maize, also called transgenic maize, starts off as regular corn. Scientists then tinker with the genes of the plants to produce more desirable traits.
Bt corn is one example of modified maize. Bt corn is regular corn that has been implanted with bacteria naturally found in the soil called Bacillus thuringiensis. The crystalline proteins produced by this bacterium are toxic to most of the natural pests that plague corn plants. By inserting these proteins in the genetic material of the plants, the corn produces toxins that kill off any invading insects that try to destroy the plants.
When weeds take over a growing field, they absorb valuable nutrients from the soil. Without the full benefit of these nutrients, plants are less hardy and produce smaller crops. Some strains of modified maize are genetically engineered with a resistance against chemical herbicides. Farmers can then spray herbicides on their fields to lessen the occurrence of weeds while ensuring their corn crop remains safe.
Concern exists over the safety of genetically modified crops. By introducing toxins to the plants, growers put individuals at risk for allergic reactions and health problems. Preliminary research into the effects of modified maize suggests that prolonged ingestion of some variants may lead to kidney and liver problems.
Environmental concerns arise when genetically modified plants transmit their traits to wild or unmodified versions of plants, thus reducing biodiversity. Pesticide and herbicide resistance are also issues of concern when dealing with modified crops. Because the plants are resistant to herbicides, bigger and harsher chemicals may be needed to kill off undesirable plants in the future. As insects become accustomed to the toxins found in modified corn plants, different and harsher toxins may be needed to kill off those insects.