A record number of genetically modified animals are being used in Britain's laboratories, figures released by the Government this week will show.
Animals whose genes have been deliberately altered, including mice born with a human chromosome to give them Down's syndrome, are being bred in their hundreds of thousands for experimentation.
The leap in the number of GM and mutant creatures created for animal research will shock animal welfare groups, which accused ministers of reneging on a promise to promote alternatives to live animal experiments.
But scientists said the reason for the rise reflected breakthroughs in genetics to find cures for life-threatening diseases. British laboratories used animals in at least 2.8 million experiments last year, the statistics to be released by the Home Office are expected to show. Although tests using primates went down in the past year, experiments using animals whose genes have been deliberately altered have risen by around 10 per cent . They include at least 800,000 experiments using GM fish, sheep, rats and mice.
But animal welfare groups say that millions of animals that have been bred for research but never used are "missing" from the statistics. They accuse the Government of reneging on promises to replace live animal tests with non-animal research.
"The Government has broken its promise that it would make a meaningful investment in non-animal research," said Andrew Tyler, director of Animal Aid. "The UK has the potential to become a world leader in medical research using modern, predictive non-animal methods, but without the genuine political will to make that a reality we will be remain stuck in a cycle of animal testing and unreliable results."
But scientists yesterday defended the work on GM animals and said it was vital to finding cures for terminal diseases.
British laboratories are leading the way internationally in creating a "map" of the human genome using mice. They want to create libraries of at least 25,000 different types of genetically modified rodents for tests to study each gene in the human genome. Scientists believe altering the embryos of strains of animals can help them to see how they operate with a missing gene. They are striving to create thousands of strains of genetically modified mice each with a missing gene to test the effect of genetic abnormalities.
The transgenic animals are being used in tests to find the genetic causes of cancer, Parkinson's and other diseases. Some have human characteristics inserted as embryos to create rodent-human "chimeras".
Zebra fish, which have transparent embryos enabling scientists to monitor heart problems, are also being genetically altered.
"If we are really to rise to the challenge of discovering how genes cause disease in humans we have to use these technologies to study the relationship between genes and disease. We have to create new strains of mice in which individual genes are knocked out. These mice strains are indispensable in developing new therapeutic approaches," said Professor Steve Brown, director of the Medical Research Council's Mammalian Genetics Unit.
Last month scientists applied for a licence from the Home Office to breed mice that have been genetically altered to affect the central control of food intake and energy expenditure.
The tests are designed to research obesity, diabetes and cardiovascular disease. This week Gordon Brown is expected to announce around £50m extra to fund breakthroughs in scientific research.Reuse content