28 February 1997

Clone technique could help firms replicate best

By Shelley Wright

SCIENTISTS who have successfully cloned an adult sheep from a single udder cell claim animal breeding companies may use the technology to multiply their best animals.

Dr Ian Wilmut, who led the Edinburgh research team, said that animal breeding companies had already shown interest in the use of cloning to multiply their best animals.

"It takes many years for animal breeders to transfer the progress they make in elite selection herds to the commercial farmer. A limited amount of cloning could speed up this process substantially, bringing the meat or milk yield of the average cow or sheep closer to that of the best," he said.

The researchers at the Roslin Institute, near Edinburgh, took a cell from the udder of a six-year-old ewe which was in the last third of pregnancy. The cells genetic material was transplanted to a sheep egg cell, from which the original genetic material had been removed.

Surrogate ewe

The egg, with the udder cells genetic material incorporated, was then implanted in a surrogate ewe, which gave birth to the cloned ewe lamb, called Dolly, seven months ago. Dolly is genetically identical to the ewe from which the udder cell was taken.

During the research work, using cells from adult sheep, embryos and a foetus, the scientists reported that 62% of the foetuses implanted into donor ewes were lost. That compares with an estimated 6% loss rate after natural mating.

In a paper published in todays Nature magazine, the scientists report that eight ewes in the experiment gave birth to live lambs, one of which died at birth. Apart from Dolly it is unclear from the report what happened to the other six lambs.

Disease resistance

An NFU official said the union believed that cloning could offer potential advantages in being able to breed disease resistance into livestock. But, she stressed, transferring possible applications from the Roslin work to everyday farming was a long way off. The experimental work was in its infancy and the union would continue to monitor all future research closely.

US president, Bill Clinton, who described the breakthrough as "startling news" immediately ordered an inquiry to examine the ethical and legal implications.

And animal welfare group, Compassion in World Farming, warned that fields of genetically identical livestock would be identically susceptible to disease and could be wiped out almost overnight. CIWF also criticised the researchers for carrying out science just for the sake of it, without any thought to the implications. &#42