WASHINGTON (Reuters) – Japanese researchers have genetically engineered monkeys whose hair roots, skin and blood glow green under a special light, and who have passed on their traits to their offspring, the first time this has been achieved in a primate.

They spliced a jellyfish gene into common marmosets, and said yesterday they hope to use their colony of glowing animals to study human Parkinson’s disease and amyotrophic lateral sclerosis or ALS.

Erika Sasaki and Hideyuki Okano of the Keio University School of Medicine in Japan used a virus to carry the gene for green fluorescent protein into monkey embryos, which were implanted into a female monkey, and four out of five were born with the gene throughout their bodies.