HR 206 defines “covered fish” as “any finfish, live or dead, including the gametes, fertilized eggs, offspring, and descendants thereof, that is modified or produced through the application of recombinant deoxyribonucleic acid (DNA) technologies, using DNA from an organism’s own genome or that of another species, that overcome natural physiological reproductive barriers and that are not techniques used in traditional breeding and selection.” This definition is dense and requires some unpacking.
Finfish, which are also called “true fish” or simply “fish”, are aquatic animals that have a backbone, gills, and fins. Finfish, like all organisms, are made up of microscopic building blocks called cells. Cells are composed of molecules like fats, nucleic acids (DNA and RNA), and proteins. A cell’s genome (total DNA in the cell) contains instructions that tell the cell how to function and how to interact with other cells. These instructions are encoded by a linear sequence of chemical units called “nucleotides”, strung end-to-end. The basic unit of instruction is called a gene, and each gene encodes information used for the production of other molecules, namely RNA and proteins, which operate and structure the cell. As an organism grows and its cells replicate, the DNA within the cells is also replicated and passed on. During reproduction, DNA is passed on from both parents to an offspring when a sperm and an egg (gametes) fuse to produce a fertilized egg.
HR 206 refers to genetic modifications produced by recombinant DNA (rDNA) technology, which began to emerge in the 1970’s. Generally speaking, rDNA techniques involve the combination of multiple DNA molecules from different sources to create a novel DNA molecule. This novel DNA molecule can then be introduced into the cells of an organism to add to or modify its genetic makeup and produce a particular trait.
For instance, AquAdvantage® Salmon are Atlantic salmon that have been genetically modified with rDNA technology. Specifically, a growth hormone gene from Chinook salmon (a Pacific species) was combined with a DNA fragment, called a promoter, from ocean pout, another type of fish. The ocean pout promoter keeps the growth hormone gene turned on, even when it normally turns off (during cold months). When inserted into AquAdvantage® Salmon, this elevated growth hormone promotes rapid growth, allowing for increased fishery production.
It is unclear if the definition in HR 206 of genetic modifications would include genome editing, a more nascent technology than rDNA, although it is possible. With genome editing, new technologies like CRISPR-Cas9 allow scientists to make much more precise genetic modifications across an organism’s genome than previously possible, to include adding, removing, or substituting DNA. Genome editing technologies often use rDNA as a tool to produce genome edits, but in this case the rDNA is a means to the modification and not the modification itself. It can be argued that genome editing, by default, involves the recombining of genomic DNA. However, this does not easily fit with the traditional definition of “recombinant DNA technologies” historically held by both the scientific community and the government. It remains to be seen whether this bill, if passed, would cover new technologies like genome editing.
The bill also focuses on preventing the potential escape of GM finfish, in part by prohibiting net-penning of GM fish. Net-penning is a method used in fish farming in which fish are raised in cages located offshore in the ocean or freshwater lakes. In regards to HR 206, the concern with using this aquaculture technique is that the natural environment is exposed to the waste of these GM finfish. Also, these GM finfish could be released in the event of containment failure, caused potentially by a storm or accident, which could result in competition or interbreeding of these fish with wild fish populations. Some opponents of such GM finfish also express concern about the health impact of rDNA-containing fish tissues on the surrounding environment and predators, although the evidence for such impact is disputed.