Glowing Mice The first generation of glowing mice, which shine a gleaming green under ultraviolet light, entered the world in a western Japan laboratory, where Osaka University geneticists injected mouse embryos with the DNA of a bioluminescent North American jellyfish. The project was started to develop new methods to observe the internal development of fetuses. Medical researchers will be able to use this technique in a variety of ways, including tracing white blood cells in cancer research. Also, this technology opens the door to a "more humane approach" to medical research. Now that specific cells can glow as markers, the effects can be observed without killing the animals and opening them up. The vibrant hues of the experimental mice disappear when hair grows over their bodies, but uncovered parts such as their feet and mouths will continue to glow well into adulthood. The green mice will be able to pass on their unique characteristic to the next five generations.