Transgenics - the Brave New World of Engineered Organisms
(Editor's Note: This article was originally published on October 30, 2008. Your comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)
What the mind can conceive . . .
"I wanted to get together with a friend the other day, but she told me she had to go to the pet store to pick up her new dwarf elephant. Seems she special-ordered it and the adorable fellow is about the size of a puppy, but with big elephant ears and trunk! Makes a cute little squeaky noise, too! I looked at the pet store catalog and think I might want to order a small winged pony for my farm . . ."
Science Fiction? Well, about 40 years ago it was wild fiction, but now genetic technology is not too far away from making the fanciful scenario above into reality. Take a close look at the thumbnail picture to the right. Those colorful fish are called "GloFish" and they are the result of recombinant DNA work, in which genes from a totally unrelated organism are spliced into the normal genome of a selected organism. To learn more about these fish and how they were developed, visit GloFish. While quite interesting, they are by no means the most extreme example of what has already been done in the brave new field of genetic engineering.
The idea of splicing genes together to make an organism that would never occur in nature sounds like something you'd expect to see done in a dark, creepy lab on the last day of October. However, some work like this has been completed and the results are growing in fields, maybe even near you! Genetically modified organisms, also known as GMOs, have fueled a controversy involving questions about topics like genetic contamination of natural plant populations and deleterious effects on public health. The commercial results of this work are largely plants that have been genetically modified to confer upon them resistance to insect damage or to protect them from glyphosate, an herbicide used to control weeds. A gene from Bacillus thuringiensis (Bt) has been inserted into corn and cotton so they will produce the Bt toxin. This enables these plants to become toxic to the caterpillars, reducing or eliminating the need to spray for these pests. In 2007, Bt corn and cotton plants were grown in 22 countries on 104 million acres. However, some countries have banned the use of GMO derived ingredients in food products, citing human health concerns. The GMO controversy is bound to continue for some years to come, especially as the technology develops further and more extreme genetic combinations become reality.
Cut and Paste
Recombinant DNA research became possible in the 1970s with the discovery of very special molecules called restriction endonucleases. These molecules act like very tiny and very specific scissors, snipping little pieces of DNA off a strand at certain locations and leaving "sticky ends" ready to receive and incorporate the gene of your choice. The discovery of these molecules was made by Werner Arber, Daniel Nathans, and Hamilton Smith, for which they received the 1978 Nobel Prize in Medicine.
Meanwhile, genetic engineers continue to push the edge of the envelope, having already produced such novelties as the glow-in-the-dark orchid (using genes from a firefly spliced into orchid chromosomes) and the ultimate Halloween cat, a glow-in-the-dark feline that can be spotted at night using ultraviolet light. The cats glow a festive orange color. It is not too far a stretch to imagine a jack-o-lantern that glows orange by virtue of specially selected and inserted genes. The glowing orchid produces a soft green glow on its own without requiring exposure to ultraviolet light. The possibilities seem endless. Who knows, one day we might have night gardens with flowers that glow softly in many colors.
Image credit: Public Domain from Wikimedia Commons
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