There is a flock of sheep in Edinburgh which is really almost human. But not in any superficial way - such as standing up on their hind legs and bleating "Who's a pretty boy, then?" No, their affinity with us is much more radical. They are giving birth to "transgenic" lambs, every cell of whose bodies contains a human gene.
It makes no difference to the lambs' appearance or behaviour, but eventually a flock of 100 transgenic ewes could supply enough human blood-clotting protein in their milk to supply all the haemophiliacs in Europe.
"Our tests on the milk are not conclusive," says Dr John Clark, of the Agriculture and Food Research Council's Edinburgh research station, "but we have high hopes that the agent is there, and that this will become a commercial proposition in the next few years.
"We have another sheep carrying the gene for a factor which could arrest the damage done by the lung disease emphysema. This substance, Alpha One Anti-trypsin, can be produced from human blood plasma, but not in the quantities that could be used."
The use of animals as medicine factories is only a part of the rapidly growing technology which enables scientists to manipulate the genetic make-up of animals, plants and, in theory, human beings. They have, almost within their grasp, dazzling new powers to transform agriculture and medical diagnosis and treatment.
But the swift pace of these advances has meant that ethical dilemmas unsuspected today are likely to emerge. There are fears that some mutated organism released from the laboratory might multiply in uncontrollable and dangerous ways, and deeper fears that powers gained in the search for agricultural or medical advancement might be used to tamper with the physical or mental make-up of human beings.
The art is still at a tantalizing on-the-edge stage. The exhilaration of it is apparent in the way researchers talk. "The subject is absolute buzzing," says Professor Harold Woolhouse, director of the AFRC's John Innes Institute for Plant Research in Norwich. "My grant-in-aid is about ú4.5 million, and I'm able to bring in something of the order of ú2.5 million from the private sector, mostly for genetic work."
A consortium of 10 major companies, including ICI, Unilever and Shell, is committed to providing half the funding for a ú9 million three-year programme at the institute, with a matching grant from the Government. "We have succeeded in introducing virus resistance into tobacco plants, by a rather neat molecular device, and hope to transfer this to more useful plants," Woolhouse says. Understanding how to gain entry to the tightly locked genetic codes of plant species in this way is the first crucial step towards giving them new capacities for resisting disease and withstanding extreme conditions. The great prize would be to achieve this with a cereal crop - and it is reported that Japanese researchers have just succeeded in doing it with rice.
"We have also discovered a completely new enzyme for fixing atmospheric nitrogen," Woolhouse adds. "It might make it possible to enable plants to get more nourishment out of the soil without using artificial fertilizers." The Institute has also done work on microbes, and has just succeeded in producing the first completely new streptomycin antibody constructed by genetic engineering techniques.
The potential, and the uncertainties, of the state of the art as far as animals are concerned is illustrated by a sty of young pigs at the AFRC's Institute of Animal Physiology in Cambridge which have had a growth hormone from cattle added to their genetic make-up. Analysis has shown that the gene has manifested itself in their cells, and will be passed from generation to generation. The only disappointment is that the gene has failed to engage with the pigs' growth processes: they have remained the size that nature intended.
American researchers are reported to have already produced pigs engineered to grow faster and supply leaner bacon, and to have bred frostproof potatoes and strawberries hardy enough to grow in Alaska. "But I think Britain is in the lead," says Professor Barry Cross, the AFRC's director of animal physiology and genetics research. "Our Cambridge research station has been in the forefront of all these artificial breeding techniques. Other laboratories are catching up very fast, though, and sometimes have 10 times our resources. Companies are already getting into the act, although there won't really be a commercial end product on the farm animals side for five or 10 years."
As the commercial pace quickens controversy is already brewing in the United States over a decision to allow mutated life forms to be patented. And in Britain serious public awareness of the issues is beginning to stir.
