Scientists have genetically modified cats, rabbits, puppies and more to make them glow.

The concept sounds too crazy to be true, if not cruel and unusual — and yet, it is not only possible, but actually happening. Scientists have successfully genetically modified cats, dogs, mice, rabbits and plants to make them glow. The question is, why?

Glowing Cats

Glowing kittens are the result of the Mayo Clinic scientists’ work to cure feline AIDS.

FIV, or feline immunodeficiency virus, a disease with symptoms almost identical to HIV, afflicts millions of cats which suffer and die from the disease every year. In attempts to prevent FIV in cats, scientists genetically modified them by injecting cat eggs with an HIV-resistant protein found in monkeys called TRIMCyp in the form of a lentivirus, which carried genes to the eggs.

The result was successful: injected kittens born were immune to FIV, as were their offspring.

In order to track which cats were treated, scientists also injected jellyfish genes, which encoded fluorescent protein into the eggs alongside TRIMCyp. This way, modified cells would glow a green color. Instead of having to do invasive tests, shining a blue light on the cats in the dark would allow scientists to tell them apart from untreated felines.

This research is helping the future of gene therapy, which could lead to the prevention of HIV and AIDS in humans somewhere down the line. Cats also make great subjects for research, because their brains are much better biological models than that of mice.

Glowing Rabbits

Collaboration between two universities in Istanbul, Turkey and the University of Hawaii Manoa bring glowing bunnies into the world as the newest furry creatures harboring jellyfish genes. The transgenesis technique used, which works similarly that of the Mayo Clinic, was founded by researches at UH, causing rabbits to glow bright green under a blacklight.

The overall goal, according to the University of Hawaii, is to introduce a beneficial gene into mother rabbits and collect the protein in their milk, which could lead to new and efficient methods for producing medicines.

Glowing Dogs

Dogs have also been modified, also with jellyfish genes, to glow — specifically, beagles. The first was a South Korean puppy named Ruppy in April of 2009, the ACP Hosipitalist reports: the world’s first transgenic dog.

Another notable glowing beagle is Tegon, also engineered by South Korean scientists. Tegon glows a florescent green upon interaction with the drug doxycycline or under ultraviolet lights.

Through the glowing genes injected, scientists can track symptoms and aid treatment in canines that might be applicable to humans, as well (humans and dogs have in common 268 illnesses).

Glowing Piglets

According to the Indiana Daily Student (IDS), glowing piglets have been born from a cloned sow in Beijing, China. This birth proves that transgenic pigs are fertile, and able to pass down traits to their offspring.

The IDS references genetic expert Robin Lovell-Badge, who stated that this green protein would allow genetically modified cells to be tracked if transplanted into a human.

Organs from genetically modified pigs, therefore, could be studied to solve the problem of rejected organ transplants in people.

When can I have a glowing pet?

There are currently no glowing critters available to the public, as these advances are being made for scientific and medical use only. You may soon be able to get a glowing plant, though. For now, furry glow-in-the-dark pets remain off-limits.