Last month in Japan, a very special marmoset monkey was born–one who inherited from his parents not only their marmoset DNA, but also a jellyfish gene for green fluorescent protein (GFP) that makes both the animal and his parents glow green under fluorescent light. The monkey parents aren’t the first primates to fluoresce, but they are the first to pass a genetically engineered trait to their offspring. Scientists hope to use the approach to create animal models of neurological diseases, such as Parkinson’s, which cannot be adequately reproduced in rodents–the typical subjects of genetic engineering.
“The birth of this transgenic marmoset baby is undoubtedly a milestone,” write Gerald Schatten and Shoukhrat Mitalipov in a piece accompanying the paper, published today in the journal Nature. Scientists have previously created a menagerie of transgenic animals, including rats, rabbits, pigs, cows, cats, dogs, and even monkeys (in one study, scientists created monkeys that genetically mimic Huntington’s disease), but “no study has shown transmission of foreign DNA to gametes–the sperm and egg–which is essential for the generation of transgenic offspring. These offspring could then be bred to create transgenic-primate strains,” they add.
The ability to genetically engineer primates is essential for creating more-accurate animal models of human diseases, especially neurological ones. For example, Schatten and Mitalipov say,
Mice engineered to express the cystic fibrosis gene, for example, do not develop the lung problems that typify this disorder … Disorders of higher brain function, such as Alzheimer’s disease, are especially challenging to reproduce in rodents, and here, as with many other diseases, it is our closest animal relatives–the non-human primates–that offer potentially invaluable biological models.
To create the transgenic monkeys, researchers injected viruses carrying the gene for GFP into 91 marmoset embryos. Eighty healthy transgenic embryos were then transplanted into surrogate mothers, who birthed five glowing offspring. Three glowing second-generation marmosets have been born since April.