a tale of two salmon
In case you haven’t noticed, there’s been a lot of talk in the news lately about a new genetically modified salmon, better known as “frankenfish”:
I’m bothered by the negative reaction many people automatically have to something being “genetically modified” even though there is nothing inherently harmful about the DNA from one organism being transplanted into another.
The structure and molecular composition of DNA is the same among all organisms, which means the difference between our DNA and the DNA of a salmon, vegetable, or what-have-you is the order in which the A, T, C, and G nucleotides are arranged. This order is important because DNA serves as a set of instructions for the cell. Many regions of DNA, which are referred to as genes, act as blueprints for making proteins.
Other regions of DNA don’t encode any proteins at all, but rather control when and how often nearby genes are expressed (made into protein). In the case of our frankenfish, there are two bits of “borrowed” DNA. The first is a gene from the chinook salmon that produces a growth hormone to make the fish bigger. The second bit of DNA is a “promoter” from the ocean pout. This promoter DNA sits in front of the growth hormone gene and controls when the gene is turned into protein. The end result is a genetically modified Atlantic salmon that produces growth hormone all year round and can therefore reach market size much more rapidly than regular salmon.
Genetically modifying an organism isn’t very different from selective breeding.
While opponents of genetically modified organisms are quick to point out the “unnaturalness” of transgenic critters, it’s important to realize that humans have been messing with the DNA of plants and animals for thousands of years. To quote one biologist:
“For thousands of years since we have had farming we have used selective breeding to basically generate animals that grow faster, grow bigger so that they have a higher yield.”
So how does selective breeding work? Suppose for a minute that I didn’t have the power of modern science to directly insert DNA into an organism but I still wanted to make a larger salmon. I could first mate an Atlantic salmon with a chinook salmon, which would give me hybrid salmon with about 50% Atlantic salmon DNA and 50% chinook salmon DNA. By repeatedly selecting the largest salmon and mating them back to the original Atlantic salmon, I would eventually end up with larger salmon containing mostly Atlantic salmon DNA. The seventh generation, for example, would have over 99% Atlantic salmon DNA.
Although this is a hypothetical example (it’s probably not even possible to mate Atlantic and chinook salmon), this process of selective breeding has long been used in farming, agriculture, and even dog breeding. Considering this, it seems that opposing genetically modified organisms simply because they contain modified bits of DNA (which pose no health risk in and of themselves) is a misdirected use of our energies and intellects. Can their still be problems with genetically modified organisms? Sure. But don’t look for them in the DNA. Instead, ask what effects the products of the DNA (in this case a salmon growth hormone) might have. Or what the environmental, economical, and political ramifications of the modified organism may be. When we start asking questions like these, the real conversation about genetically modified organisms can begin.