The world鈥檚 first genetically-modified monkey has been born in the US. The development paves the way for using monkeys as models for human gene-related diseases, say the researchers.
But many scientists are sceptical that large scale research on GM monkeys would be practical, desirable or even useful.
Mouse models of diseases such as Alzheimer鈥檚 and certain cancers 鈥渉ave been invaluable,鈥� says research team leader Gerald Schatten of the Oregon Regional Primate Research Center. But he thinks primates will make better models, because they are closer to humans both genetically and in size.
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Using GM monkeys in research into new treatments, including gene therapies, should hasten the development of human cures, he says. 鈥淲e could, for example, introduce an Alzheimer鈥檚 gene, to accelerate the development of a vaccine for that disease.鈥�
鈥淧rohibitive expense鈥�
But Dave Kerr, head of the Institute of Cancer Studies at Birmingham University, UK, does not think that cancer researchers will rush to use GM monkeys.
鈥淵ou鈥檇 think that in evolutionary terms, because monkeys are so many steps closer to man than mice, they鈥檇 be ideal. But mice are surprisingly good for testing new drugs, for example,鈥� he told 快猫短视频.
鈥淎lso, you can do things such as transplant human tumours into mice, which I couldn鈥檛 really envisage doing in monkeys. Ethically nobody would like the idea of increasing primate research and the costs would be prohibitively expensive.鈥�
Dave King of the Campaign Against Human Genetic Engineering says the researchers have taken 鈥渁 dangerous step.鈥� He thinks the work will encourage scientists to try 鈥榞ermline鈥� gene therapy in people. This involves inserting a gene that is passed on to offspring.
鈥淭his would lead to a new form of eugenics, where we start designing our children according to our whims,鈥� he says.
Handy ANDi
The GM monkey is called ANDi (for 鈥淚nserted DNA鈥�, written backwards) and is now three months old. He was genetically modified at the egg stage.
The team used a virus to insert a gene for green fluorescent protein (GFP) into 244 eggs. These eggs were then fertilised. Forty implanted embryos resulted in five pregnancies, and three live births.
But DNA tests showed that the GFP gene was only present in ANDi. However, the team cannot detect any fluorescence from ANDi, and so do not know if his cells are producing the fluorescing protein.
It may be that they are not producing enough of the protein for it to be detectable. Or it could be that the transgene will not 鈥渁ctivate鈥� for up to a year after his birth, says Schatten. Delayed activation of the inserted gene has been seen in other transgenic animals, he says.
Cautious welcome
Whilst acknowledging the potential, many prominent researchers remain unconvinced about the usefulness of GM monkeys. Martin Evans of Cardiff University led the team that created a GM mouse model for studying cystic fibrosis.
鈥淭here is some truth in the claim that GM monkeys would be better models than mice for some purposes but it would be far more ethically objectionable,鈥� he says.
Norman Nevin, at Belfast City Hospital and a member of the UK government鈥檚 Gene Therapy Advisory Committee, thinks primate models would be valuable for gene therapy research.
But he agrees that most researchers could not afford to create or keep GM monkeys. 鈥淚 doubt they would be used in the UK,鈥� he told 快猫短视频.
More at: Science (vol291, p309)