How to Clone a Herd

By Jeffrey Kluger

First there was Dolly the Scottish sheep. Then, last July, came several litters of cloned mice. Now scientists at Japan's Kinki University have produced something even bigger and a good deal tastier: eight identical calves cloned from a single cow.

Writing in last week's issue of Science, the Japanese researchers report that they achieved this feat of bovine photocopying using two different types of cells, taken from a single cow's ovaries and fallopian tubes. Those cells--all carrying the same genetic payload--were introduced into cow ova whose genes had been scooped away. Ten such identical embryos were then implanted in the wombs of surrogate cow mothers, and all but two came to term.

No one knows why the Kinki team managed to bat .800 (while Dolly's creators needed 29 embryos to get one hit). Japanese scientists hope to learn more when other calves--cloned from liver, kidney and heart cells--are born next spring. The beef industry is anxiously awaiting the answer: the clones come from a line of prize cows whose meat sells for $100 a pound.

--By Jeffrey Kluger