The last decade saw an upcoming market segment – the world's first “glow-in-the dark pet” market.

Ruppies were the world's first transgenic dog which carries fluorescent genes.

Genetic engineers took a fluorescent protein, much like that produced by some sea anemones, and inserted it into the cell of a beagle. The offsprings of such dogs possess the same fluorescent gene as their mothers.

The name "Ruppy" is a combination of the words "Ruby" and "Puppy".

Then the transgenic fluorescent green pigs got underway in Taiwan, which is also the home to the world's first transgenic glowing fish.

In 2006, a research team at National Taiwan University successfully bred three male transgenic pigs by injecting fluorescent green protein into embryonic pigs that they hoped would boost the island's stem cell research.

In January 2008, a fluorescent green pig in China gave birth to two piglets which shared their mother's transgenic characteristic after she mated with an ordinary pig.

Below are some of the most rare and spectacular pictures of the genetically modified glowing animals.