7 genetically modified animals that glow in the dark
This is no party trick. These radiant sheep, dogs, and cats help further research of human
diseases
By Lauren Hansen | April 30, 2013
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This sheep glows green thanks to a florescent jellyfish protein inserted at birth.
Screen shot
1. Sheep
Good news, nighttime shepherds: Sheep can now glow in the dark. Well, technically, only nine
of the wooly animals can. And they're in Uruguay.
When these sheep were born in October 2012, scientists at the Animal Reproductive Institute of
Uruguay immediately injected them with a green protein found in the Aequorea Victoria
jellyfish. As the sheep grew, they looked and acted like any other four-legged balls of fluff,
except that they gave off a greenish glow after being exposed to certain ultraviolet light. Check
'em out:
Typically, these green fluorescent proteins are used to monitor the activity of altered genes. They
have proved to be of great help in the study of diseases. In fact, the method's scientific pioneers
were awarded the Nobel Prize for chemistry in 2008. In the case of these sheep, scientists hope
that one day they'll be able to use this sort of procedure to create animals with super health-
boosting milk. Here, a look back at the radiant animals at the center of these genetic studies
throughout the last decade.
2. A rabbit
(Ekac.org/Chrystelle Fontaine)
This endeavor was actually an artistic one. Eduard Kac is an artist known to use genetic
engineering techniques to create unique living works of art. In May 2000, Kac introduced the
world to his "GFP bunny," an albino rabbit named Alba that glowed fluorescent when exposed to
blue light. Alba was actually just one component of the project, which was also supposed to
include a public debate about the practice of manipulating genes in animals for research. Kac
wanted to conclude the project by taking Alba home to live with his family. A research institute
in France actually created the rabbit for Kac — the florescent jellyfish protein was injected into a
fertilized rabbit egg — and later hesitated over releasing the animal due to protests from animal
rights groups over Alba's very creation. The scientists also claimed that they never agreed for
Kac to take the bunny home. Two years after Alba was born, and long before Alba could make
her trip to the states, the unique rabbit died — an abrupt end to the battle between science and
art.
3. Pigs
(REUTERS/China Daily)
In 2008, scientists in Taiwan claimed to have a world first: Pigs that glowed from the inside out.
While other researchers had bred partially fluorescent pigs, these genetically modified pigs had
not only glowing skin and eyes, but also organs, including the heart. Scientists added DNA from
fluorescent jellyfish to more than 260 pig embryos, which were then implanted into eight
different sows, four of which became pregnant. The result was three male piglets whose eyes,
teeth, and snouts had a slightly greenish tint during the day, but would glow entirely green in the
dark after being introduced to a blue light.
4. Monkeys
Newborn transgenic marmosets Kei (left) and Kou, and their feet under ultraviolet light. (AP
Photo/Erika Sasaki)
In this 2009 study, the same jellyfish DNA injection was used, but for different purposes.
Scientists in Japan wanted to see if the jellyfish gene was inherited by the second generation of a
genetically modified monkey. The team at the Central Institute for Experimental Animals in
Kawasaki, Japan, added a fluorescent gene to the marmoset embryos, which were then
transferred into surrogate females who produced five live births. All of the modified marmosets
carried the genes in their body. When they produced offspring, two passed the fluorescent gene
onto their young. This was the first time a genetically modified animal passed such genes down a
generation. Researchers said it could be a major step in understanding Parkinson's and motor
neuron disease.
5. Dogs
A
3-month-old beagle glows in the dark under ultra-violet light (left) but looks like any other
puppy in the daylight. (REUTERS/Jo Yong-Hak)
A 2009 experiment by a team at Seoul National University reportedly produced the first
transgenic dog. Five beagles were created by cloning fibroblast cells that express a red florescent
gene produced by sea anemones. Under natural light you can see the faint essence of the red
protein under the pale skin. In the dark and under an ultraviolet light, the dogs glow a reddish
orange. The five healthy dogs eventually grew to spawn their own florescent offspring. The
experiment was meant to prove the principle of transgenic animals, particularly dogs, who, due
to their lifespan and reproductive cycle, are good stand-ins for human disease research. Two
years later, a team at the same university bred a beagle name Tegon whose fluorescent gene
could be controlled. When the dog eats food containing a doxycycline antibiotic and then is
exposed to ultraviolet light, it glows green. When the drug is no longer added to the food, the
glow eventually fades. Scientists say the study opens opportunities for better understanding
genes that trigger fatal diseases, like Alzheimer's and Parkinson's, in humans.
6. Cats
A
glowing kitten stands next to a normal cat (Mayo Clinic)
Cats are susceptible to a close relative of HIV called feline immunodeficiency virus. The viral
disease infects mostly feral cats, of which there are reportedly a half a billion in the world. In a
2011 study, a team of scientists from the U.S. and Japan inserted a gene into cats that helps them
resist this feline form of AIDS. Then, to be able to easily mark the cells, scientists also inserted
the green fluorescent protein. Both genes were transferred into feline eggs. They were then able
to more readily monitor how the resistant gene developed in the cats' bodies when looking at
them under a microscope. Like the other animals, the cats appeared normal during the day, but
could glow at night if prompted.
7. Fish
(University of Exeter)
One of the biggest downsides to helpful industrial products like, say, plastic, or female
contraceptives, is that they contain bad chemicals called endocrine disrupters. These substances
become pollutants that harm animal and human bodies. They have reportedly been associated
with lower sperm counts and breast and testicular cancers. So you can see why scientists may
want to study them. The problem has been that it is difficult to track the endocrine disrupters
once they enter the body. And so a team of scientists used green fluorescent proteins and
genetically engineered zebrafish to glow in places where an endocrine-disrupting chemical is
present. As we've previously illustrated, the fluorescent protein doesn't interfere with the body,
but, when studied under a microscope, can be easily found. The glowing green areas within the
fish then become a roadmap for scientists homing in on the pollutants' potential health impacts.
Sources: ABC News, BBC, Discovery, The Guardian, National Geographic, NBC News, New
Scientist (2), The Register, Taipai Times