Bleating cousins

IT TOOK a simple laboratory dish to create one of the most awesome break-throughs in science - hundreds ofgenetically identical sheep. The feat wasrecently performed by Ian Wilmut,Keith Campbell and their colleagues atthe Roslin Institute in Edinburgh. Theprocess itself does not seem too complex - taking an embryo from a pregnant sheep and allowing it to multiply inculture dishes; removing eggs fromfemale sheep and then stripping them oftheir genetic material; and finally, fusingthe cultured cells with the eggs in testtubes to create new embryos withsimilar genetic material. These werethen-implanted in a surrogate mothersheep. And the result: the first twogenetically alike sheep, christenedMegan and Morag.

What the future could hold for theseexperiments is tremendous. In theory,the technique would hold good to createidentical humans. Imagine an array ofbudding Einsteins or Kasparovs dottingthe earth. "It's very impressive," saidDavid White, a lecturer at theCambridge University and a founder ofImutran, a biotech company producinggenetically engineered pigs, of theScottish achievement.

While cloning has been conductedin laboratory animals like rats and rabbits with partial success, this is the firsttime that it is being carried out in a largeranimal. "The production of cloned off-springs in farm animal species couldprovide enormous benefits in research,agriculture, and biotechnology,"according to Campbell and his colleagues. Cloning of sheep itself offersimmense possibilities - sheep with better wool, stronger hooves and greaterresistance to diseases could be producedby adding the right genes to the culturedcells. Further, the new"process fastensthe introduction of a new genetic trait inanimals, while earlier it used to takeyears of cross-breeding to developthe same.

A word of caution, however. Asudden outbreak of a disease, to whichresistance has pot been developed,could catch the identical breedsunawares, leading to a mass extinction.

This is what had occurred in Chilesometime ago, when asexuallyproduced blackberries were ravaged bya rust fungus which did not affect thesexually produced variety. Ultimately,diversity in nature is a fat more pleasingsight than unending streams of similaranimal and plant species.