Why scientists are doing fluorescent pets?

Dear Dr. ReporterGene, what is going on? Why scientists are taking our dogs, rabbits, pigs, fishes and now even cats and after some buzz manipulations, they transform a cute pet into scary fluorescent beast? What is the point in making the cat to glow?

A: If a laboratory animal glows, it is proof that a genetic manipulation has been done. Our genome (our DNA) is too small to hold it down with mini-forceps and to model it like nakiplast: if a scientist wants to modify a genome, he will use more indirect methods requiring at the end some proof that the DNA has been actually changed. The set of methodologies generally called 'transgenesis' refers to the modification of the genome by insertion of a new gene that normally gives to the host genome a new function. Since most transgenic techniques are species-specific (if a technique works for rats maybe does not works for frogs) scientists are urged to develop new transgenic techniques to study the major number of species* from a genomic point of view. Usually, for the proof of actual transgenesis, scientists are first introducing a proof gene (aka a reporter gene) like the one that gives to the animal all the instructions to build the green fluorescent protein. Therefore, if your pet glows in the dark, it is because there is a new fluorescent gene in its genome.
A fluorescent cat, like the one in the picture published today by Dr Poeschla in Nature Methods, is the proof of concept that a new transgenesis technique works for cats. In addition, because GFP is visible at the exterior of the animal and because it is possible now to couple the expression of a reporter gene with any other molecular gear reporting any other physiological activity interesting for human health, this technological advance is the promise that biomedical research will be conducted in future times from an exterior point of view, without the need to kill the laboratory animal. Today, this is only a promise, and it will probably require decades, because in science every step need a proof, but it is a promise than I'm playing hard to get it done.

* we need to study the major number of species because different animals have different similarities to human biology: for instance our brain is more similar to the cat brain than to the mouse brain.
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Pimprapar Wongsrikeao, Dyana Saenz, Tommy Rinkoski, Takeshige Otoi and Eric Poeschla Antiviral restriction factor transgenesis in the domestic cat  - Nature Methods (2011) doi:10.1038/nmeth.1703