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Hidden sacrifice

发布时间:2019-03-08 08:15:20来源:未知点击:

By Andy Coghlan AN ALARMING number of mice are being slaughtered because they don’t take up the DNA that genetic engineers are trying to insert into them. Bioethicists voiced concern over the waste of life, and its effects on the emotional wellbeing of the technicians who have to dispatch the animals, at a meeting in London last month on the effects of biotechnology on animal welfare. Most biologists agree that transgenic technology has the potential to bring huge advances in fundamental research and medicine. By altering mouse genes, they can unlock the genetic secrets of development, or create animal models in which to study devastating human diseases. Laboratory animals have always had to be be humanely killed, once they can no longer be used in experiments or for breeding. But genetic engineering makes the problem worse. When researchers inject new genes into animal embryos, only between 1 and 10 per cent of them will incorporate the gene. And while fewer animals in general are being bred for scientific experiments, transgenic mice are a growth area. Their use in Britain has increased sevenfold during the 1990s (see Figure). The Home Office, which regulates animal experiments in Britain, says that the “waste” animals should be included in the statistics for transgenic procedures. But some observers believe many are being left out. “It’s very difficult to work out the exact number killed surplus to requirements,” says David Morton, head of the centre for biomedical ethics at the University of Birmingham. “I think a lot of people may cull them and not count them.” Richard McGowan, a spokesman for the Fund for the Replacement of Animals in Medical Experiments in Nottingham, wants scientists to look for ways of reducing the wastage. One option would be to use transgenic “failures” to provide tissue for research, instead of the hundreds of thousands of animals that are specifically bred for this purpose each year (This Week, 25 October 1997, p 25). But McGowan concedes that matching supply to demand may be difficult, as the scientists involved may be in different labs, and require the animals at different times. So until transgenic techniques improve so that genes can be more reliably incorporated into the genomes of mouse embryos, much of the wastage is likely to continue. In the meantime, Morton believes that scientists should consider carefully the effects of the boom in transgenic animals on the technicians who have to kill the surplus animals. “They are often told to mop up afterwards,” he says. One senior animal technician at a leading British university says that she has noticed an increase in the numbers sacrificed as genetic engineering has expanded: “My remit is to ensure we don’t overbreed animals, but with transgenics, you can’t do anything about the surplus.” She, for one, is disturbed by being asked to kill so many animals. “I go away feeling physically and emotionally exhausted, and I think it’s important for people to understand how we feel.” She believes that an anonymous questionnaire would reveal the extent of emotional problems among technicians. John Gregory, chairman of the Institute of Animal Technologies, which represents Britain’s animal technicians, says his organisation is open to the idea of conducting a survey,