Cows make cloning seem easy

Four fifths of the cloned cows reached maturity

		By BBC News Online's Ivan Noble

A study of 30 cow clones in the United States has found none of the drastic abnormalities which have been seen in other cloning trials.

We haven't observed any of the genetic defects or abnormalities reported in the popular or scientific press

Robert Lanza
Advanced Cell Technologies

Animal clones often have genetic defects, problems with their immune systems, and weight problems.

The US group, however, had no such trouble and two of the cattle clones have even had apparently normal offspring.

The study's authors warn against seeing the results as an encouragement for the handful of people who want to clone a human being.

'No abnormalities'

Robert Lanza, of Advanced Cell Technology in Massachusetts, and colleagues looked at a cow cloning experiment which led to 110 pregnancies.

Almost three-quarters of the pregnancies aborted spontaneously, far more than with IVF treatment, where a quarter are expected to end before term.

But of the 30 calves that made it to birth, 24 lived to maturity, a figure which compares well with what happens to cows born after conventional reproduction.

"Results of general health screens, physical examination, and immune function were normal for all of the animals, including laboratory analysis of blood and urine, and we haven't observed any of the genetic defects or abnormalities reported in the popular or scientific press," Dr Lanza told the BBC.

Encouraging results

"All of the data collected reinforce the view that these animals are clinically and phenotypically normal," he said.

This paper surely confirms that it would be irresponsible to attempt to clone a person

Ian Wilmut
Roslin Institute

Dr Ian Wilmut, of the Roslin Institute in Edinburgh, UK, and co-creator of Dolly the sheep, describes the study as "encouraging" but says that it needs to be seen alongside other studies which did observe unusual deaths.

"These include the calf that failed to develop an immune system and died when just over seven weeks of age, described by Renard and his colleagues.

"Given that 73% of pregnancies ended in abortion and 20% of the calves died soon after birth, this paper surely confirms that it would be irresponsible to attempt to clone a person," he said.

"It also raises the question of whether there should be widespread use in livestock production until the technique is more efficient," he added.

The cow clone study appears in the journal Science.