Genetically Modifying Fruits and Vegetables
DNA technology has enabled scientists to genetically modify crops to enhance beneficial qualities and to boost their ability to withstand pests and inclement weather. The skeptics are concerned about corporations focused more on their bottom line than on the health of consumers, but others are cautiously optimistic about the potential life-saving changes that are possible.
GMO’s In Use Today
- The treatment of diabetes was revolutionalized in the 1980’s when researchers were able to alter the DNA of a bacterium and simply manufacture insulin in a laboratory rather than using hormones extracted from the pancreas of pigs or cows ( … gross! )
- Though most GMO fruits and vegetables haven’t been approved for human consumption, a large percentage of the corn grown in the US to make ethanol is genetically modified to tolerate pesticides and to be resistant to bugs.
- Soybean and canola crops have been altered to produce plants with higher levels of healthy oils.
Changing a Genetic Sequence
The process begins by locating the genetic sequence of a favorable trait on a strand of DNA. Scientists apply enzymes to the strand to chop it into fragments and generate copies of the targeted gene; a method that has been used in forensic DNA analysis for years.
The isolated trait is then incorporated into a plasmid. A plasmid is a fragment of DNA found in the nucleus of a bacteria separate from its chromosomal DNA. The plasmid is modified with the genetic sequence for the new trait and then replaced in the bacteria or into a different host. (image credit: www.kahnacademy.com)
A New Creation
Incorporating the synthetic gene depends on the type of host. For instance, bacteria being modified to cultivate useful enzymes are known to readily accept the plasmid and immediately produce offspring with the altered genome. A virus could have its genetic sequence changed and then be allowed to “infect” the host organism.
In a more complex process, a modified plasmid could be directly injected into the nucleus of a plant cell. The plasmid is then “flagged” with a gene sequence that produces an antibiotic so researchers can expose the plants to a particular disease and then easily determine which ones have reproduced with the new genome. Or, small metal pellets could be coated with fragments of DNA and then “shot” into plant cells at high speed to infiltrate the cell membranes.
Cautious Oversight of GMO’s
These technologies are way beyond the practices of cross-pollinating plants and selectively breeding livestock; strategies that have evolved over thousands of years. The research involving recombinant DNA technology is carefully regulated by the FDA, the EPA, and the USDA.