The mice that glowed

These are the world's first fluorescent mice, created by adding genes from a jellyfish to the DNA of a mouse. The extra genes produce a phosphorescent protein: the result is that every cell in each mouse glows when viewed under artificial light. The jellyfish glow both green and purple, but in each mouse only one colour predominates.

Mice are a favoured target for such gene research, which brings together genes from different species, because they mature rapidly and so quickly indicate whether the gene addition has worked. This litter of glowing mice also marks another important step in the progress of genetics. In the past, such protein injections into genes were only possible with certain insects and fish, not mammals.

The five mice pictured were born earlier this week at the Microbiology Disease Research Institute in Osaka University, Tokyo. The cells produce an extra protein, due to the presence of genes added to the mouse DNA. Those were extracted from aequorea victoria, a species of North American jellyfish which glows under light.

The researchers explained that this technique could be used to trace the growth and progress of cells in laboratory animals without using surgery. Presently, the search for cancer cures, especially the most hopeful ones involving genetic action, requires surgical examination. While some genes have been added to try to cure cancer in such trials, surgery is still required to see whether the cells are using them. But adding genes to DNA is still a hit-or-miss affair.

However, if the anti-cancer genes could be inserted with the phosphorescence genes, then it would be much simpler to see whether the genetic modification had been successful: a light source would be all that was needed.

"This would not only aid in cancer treatment and organ transplants but can be widely used in biotechnology in general," said one of the researchers in the team headed by Masaru Okabe, who announced the results.