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Transgenics, while still in its infancy as a field, is nothing new at this point. We already have genetically modified corn, rice, and numerous other plants that have been altered to produce crops that are more disease resistant, more nutritious, or just about anything else the plant geneticists have been able to dream up.
Now labs are starting to branch into animals. Recently researchers in Taiwan created some pigs that are a tad – different. Using genetic material from jellyfish, the National University of Taiwan, Department of Animal Research treated 265 pig embryos, implanted them in sows, and managed to produce three live births, all male, all glowing – but not just with good health. These pigs glow green down to the cellular level. Even their internal organs glow green, which is what distinguishes them from previous green transgenic pigs. The hope of the researcher is that these pigs can breed true, leading to a reproducible line of glowing green pigs.
The pigs become somewhat less surprising when you look at the success several Asian labs have had with fish. Three years ago, in 2003, the University of Singapore produced a line of transgenic zebrafish. The zebrafish were treated with genes from sea anemones, and the result was a bright red, glowing fish. The Glofish are now an established line, and an established brand name. The fish are being marketed in the US as a novelty pet, and other colors have been created to enhance their appeal for that purpose. Researchers, however, have much broader uses in mind for their fish. It is their hope to breed versions of the Glofish whose luminescence is reactive to certain environmental chemicals – some pollutants, for example. Then it would be possible to use the Glofish as organic pollution detectors; place them in a waterway, and check whether or not they glow to determine if a particular pollutant is present.
Because of the broader applications envisioned for the Glofish, it has become somewhat more controversial than the pigs are ever likely to be. Environmentalists are concerned that released Glofish may pose a threat to wild zebrafish populations. They posit several possible scenarios. One of the most alarming has been dubbed the “Trojan Gene”. In this version, the glowing display of the transgenic fish would render them irresistible as mates, thereby causing a large-scale mixing of the wild and transgenic populations. However, the glow could also make them an easy mark for predators. The combination would result in a crash in the zebrafish population as the first mixed generation became easy prey. The “Trojan Gene” is one of several posited hypotheses of the effect of released Glofish, there are several others with results ranging from nominal to devastating. Regardless of which set of hypotheses prove to be true, it will be take a lot of research and testing before any country is likely to allow the fish to be used in an uncontrolled environment.
Whatever the obstacles to their use in the wild, the idea of organic detectors is an intriguing one that is unlikely to go away, even if environmental concerns keep them in the lab. Using transgenic animals in this way could allow detection or tracking of effects that would normally require an animal be biopsied or sacrificed to allow close study. The line of green pigs, once established, is destined for use in stem cell research. A glowing green stem-cell culture could be tracked visually as it grew and interacted with a host animal, no biopsies needed. Glofish, if the researchers manage to make them pollutant specific, could be used to study toxin uptake, as the transparency of small fish would make it possible to watch the various sections of the fish start to glow.
It doesn’t take much imagination to see a future with animals that can be modified in almost any way desired. Technicolor sheep may one day be a common sight. Whether this is a direction we wish to travel is something yet to be seen. What happens in the next few years with the transgenic animals we have now could easily set the direction we follow for years, or decades, to come.