The importance to medical research of genetically modified (GM) mice was highlighted yesterday as official statistics showed that their use in scientific experiments has exploded over the past decade.
Almost all of the increase in animal testing since 2000 has resulted from the revolution in research that means biologists now routinely alter the genes of laboratory mice in order to mimic a range of human diseases, from Alzheimer's and Parkinson's diseases to cancer and cystic fibrosis. For the first time, the number of scientific experiments and other "procedures" involving lab animals that have been either genetically modified or afflicted with harmful genetic mutations has exceeded the number using normal animals. More than a million GM mice were created in Britain last year alone. Such tests have already enhanced our understanding of a range of human diseases, from cancer to Alzheimer's and the common cold.
The total number of scientific procedures involving animals fell by 1 per cent last year, Home Office figures showed yesterday, but there was a steady and significant rise in the use of GM mutants, which accounted for nearly 53 per cent of the 3.6 million procedures carried out in Britain.
Most of the increase resulted from using or breeding GM mice for medical research, in which human diseases can be mimicked in animals as a result of changes to their DNA. This allows scientists to study human disorders in more detail under controlled conditions, and to test drugs and other potential treatments on animals before trying them on people.
About 3.5 million animals were used in last year's 3.6 million procedures - about 1 per cent fewer than were used in 2008. However, the number is still the second highest for 20 years and reflects a continuing upward trend, due primarily to greater use of GM animals and those with harmful genetic mutants.
Breeding to produce GM animals, mostly laboratory mice, and others with genetic mutations rose by 10 per cent last year to 1.5 million procedures. For the first time, experiments with genetically "normal" animals accounted for less than half of the total - 48 per cent. There was a 9 per cent rise in scientific procedures involving mice.
Researchers say the ability to breed GM mice that mimic human diseases, or have other traits that would not exist naturally, has revolutionised our understanding of the fundamental biology of human disorders and led to many breakthroughs in treatments. However, those opposed to vivisection question the value of such work, arguing that it offers only limited benefits and causes more suffering for animals.
Gemma Buckland, a science and policy officer at Humane Society International, an animal rights charity, said it was troubling to see such a rise in the use of GM animals that often suffered organ damage, physical deformities and tumours. She said that despite "very bold claims" made about their medical application, the truth was that "GM technology is still merely an attempt to add or knock out a gene in a different species to make it a less crude surrogate for humans".
"In [most] cases, the animal doesn't bear the …