Scientists in Uruguay modified sheep's genes with luminescent jellyfish protein that causes them to glow green in UV light. (Photo : Fundación IRAUy / J. Calvelo)

Scientists in Uruguay have genetically modified sheep to glow in the dark. The fluorescent sheep are a world first, the scientists report.

The flock of nine lambs was born last October at a farm belonging to the Animal Reproduction Institute of Uruguay, an nonprofit organization affiliated with the Pasteur Institute's genetically modified animals unit. The laboratory incorporated a green fluorescence protein into the genes of the sheep, which will glow when exposed to certain ultraviolet light, making the the ruminants easily identifiable as genetically modified.

Other than glowing green in UV light, the sheep look and behave normally. Scientists modified the sheep's genes with the fluorescent protein of the Aequarea jellyfish.

"We did not use a protein of medical interest or to help with a particular medicine because we wanted to fine-tune the technique. We used the green protein because the color is easily identifiable in the sheep's tissues," said Alejo Menchaca, the head of the research team.

Menchaca said the sheep are living a normal life, perhaps even slightly more luxurious than typical sheep.

"They are out in the field as any other sheep, but in better conditions, not the traditional breeding system. They are well looked after, well fed and very much loved," he said, according to the South Atlantic news agency Merco Press.

NBC station WPTV obtained a short video of the sheep, below.