A post on Reporter Gene describes how a team of Korean researchers has created the first transgenic dog. She expresses red fluorescent protein (RFP) in all of her cells, causing her to glow quite nicely under normal light, and even more strongly under the wavelength of light that excites RFP. The researchers named her "Ruppy," a contraction of "ruby puppy." And, I must say, she's adorable.
Above: Ruppy, the first transgenic dog. In panels b and c, Ruppy's paw is compared to the paw of a dog that does not express RFP.
"Transgenic" simply means expressing a "transgene," or a gene normally found in another organism. Transgenic mice are commonly used to study human genes in a model organism, because mice are small, easy to work with, and their genome has been well-characterized over the years. Not many other transgenic species are available. Transgenic rats are in the works in many places -- helpful because although rats may look like they're just big mice, they're actually more intelligent than their smaller rodent cousins. Transgenic rats allow us to combine powerful genetic manipulations with a wider variety of behavioral assays. Finally, some scientists at Emory have created transgenic monkeys to use in the study of neurodegenerative disease. Non-human primates may be the best way to model the human brain, and some rodent models of neurodegenerative disease don't produce the same symptoms as in humans. One reason might be that the human symptoms take many years to accumulate, and mice only have about a two-year lifespan. Transgenic monkeys may help us better understand the diseases than a rat or mouse would.
As someone who has kept dogs as pets, it's hard for me to think about using them as research animals. Beagles like Ruppy (and like my beloved pet, Teddy) are a common breed used for research because of their small size and gentle temperament (terriers are also small, for example, but they are more aggressive). While I recognize the importance of research that's been conducted in dogs, I'm not sure that I could personally work in a lab that studies them, due to my emotional involvement with the species. Happily, the use of dogs and cats in research has been declining (down by over 50% since 1979, according to the CDC), as scientists have found ways to conduct their experiments in rodents or in non-animal models. The smaller number of dogs still used for research are kept by thoughtful scientists who attempt to minimize their stress and provide them with a comfortable environment. Transgenic dogs like Ruppy will help those who still must use companion animals for their experiments develop less invasive techniques for studying these model organisms.
Hong, S., Kim, M., Jang, G., Oh, H., Park, J., Kang, J., Koo, O., Kim, T., Kwon, M., Koo, B., Ra, J., Kim, D., Ko, C., & Lee, B. (2009). Generation of red fluorescent protein transgenic dogs. Genesis DOI: 10.1002/dvg.20504
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