Call for better cloning research

By Ania Lichtarowicz
BBC Health reporter

Nuclear transfer: The nucleus of a cell is transferred into an 'empty' egg

The biological process behind cloning needs to be better understood to make it more efficient, say scientists.

The experts, who include one of the creators of Dolly the Sheep, believe cloning research so far has been done in a haphazard way.

Writing in the journal Nature Reviews Genetics, they say it needs to be more systematic if potential treatments for diseases are to be delivered.

Numerous animal species have been cloned but with mixed success.

In species like mice and pigs it is fairly successful but attempts in others, like sheep and cattle, have resulted in very few cloned animals.

Clones are lost at the earliest developmental stages, during pregnancy, and often after birth, from a range of defects.

It is not properly understood why there are these differences between species. The group of Scottish-based scientists says this lack of knowledge must be tackled to improve techniques.

Genetic information

Professor Ian Willmut is one of the scientists who cloned Dolly the Sheep - the first animal to be cloned from an adult cell.

"Normally during fertilisation you have an egg and a sperm coming together and their genetic information is packed in special ways for the egg and for the sperm," he told the BBC.

"What we do is take out the genetic information from the egg and put in the genetic information from a cell which is packed in a completely different set of proteins.

"What that egg has to do is struggle to reassemble that genetic information in a way in which it can control normal development."

Medical uses

Eventually, scientists hope to use cells from cloned human embryos in treatments for diseases like diabetes and following heart attacks to replace damaged heart tissue.

In the next few years, the goal is to use embryo clones to understand conditions like motor neurone disease.

But this will not be possible unless scientists know exactly what is going on during the cloning process.

There are of course concerns that this type of work could lead to cloning humans - something these scientists find ethically unacceptable - but it could also show why reproductive cloning is not viable.