They have created strains of laboratory mice that suffer symptoms similar to those caused by the human disease, which opens the way to developing new drugs and testing revolutionary treatments such as gene therapy.
By inducing a mutation in the mouse gene responsible for transporting chloride ions across cell membranes, the researchers have created mice that are effectively healthy carriers of cystic fibrosis.
When these mice are crossbred with each other, they produce offspring that develop the full panoply of symptoms, including the build-up of thick, sticky mucus secretions in the lungs, common in children with the disease.
Until now, cystic fibrosis was known only in humans, and the lack of a suitable animal model on which to test new drugs and treatments had effectively frustrated the quest for a cure.
A team of researchers, led by David Porteous from the Medical Research Council's Human Genetics Unit at the Western General Hospital in Edinburgh, took nearly three years to complete the research, which is published in today's issue of the journal Nature.
Professor John Evans, director of the unit, said: 'What we've got is a real animal model of the human disease. We can now start varying therapy to see how the disease progresses in these animals. We can't do that on humans.'
Martin Scott, of the Cystic Fibrosis Research Trust, which funded the work at a cost of pounds 200,000, said the mice should have a 'tremendous impact' on the search for a cure. Gene therapy, where healthy genes are used to replace defective ones, could now be tested on animals to ensure it was safe for humans. 'One can now expect a great mushrooming of knowledge and therapy.'
American researchers last month revealed that they had also created cystic fibrosis mice but those animals did not have the full range of symptoms and all died soon after birth, making them effectively useless in medical research.