Go-ahead for hybrid human-animal embryos

A white paper published last year proposed banning the use of hybrid embryos amid fierce opposition to the research from pro-life groups.

But yesterday, the draft Human Tissue and Embryos Bill reopened the door for such research, which scientists claim is essential if they are to find treatments for serious diseases such as Alzheimer's.

The bill allows scientists to create "cytoplasmic" hybrid embryos, which are 99.9 per cent human and 0.1 per cent animal, such as cow or rabbit.

The legislation also goes further, in that it allows human embryos to be altered by the introduction of animal DNA.

It is hoped that the hybrid embryos - also referred to as chimeras - could help tackle the shortage of human eggs available for research.

Caroline Flint, the public health minister in Westminster, denied the government had staged a climbdown on the hybrid issue. She said that the white paper had always left the door open for specific research on a case-by-case basis.

True hybrids - creatures created by the fusion of sperm and eggs - remain outlawed. In all cases, it remains illegal to allow hybrid embryos to grow for more than 14 days or for them to be implanted in a womb.

This period allows enough time for scientists to harvest stem cells for their work.

The consultation on the white paper was criticised for allegedly being hijacked by members of the pro-life lobby, who are opposed to such research.

Ms Flint said scientists had since come forward to make their reasons for needing to use hybrid embryos much clearer.

While some grey areas remain, scientists welcomed the U-turn in the bill, which will now face parliamentary scrutiny.

Professor Robin Lovell-Badge, of the Medical Research Council National Institute for Medical Research, said: "I am very pleased the draft bill proposes research involving mixtures of animal and human material.

"This research has many potential benefits for the understanding of disease and for treatments, and it should not be feared."

Professor Chris Shaw, from Guy's, King's and St Thomas's School of Medicine in London, who wants to study motor neurone disease using stem cells, welcomed the decision, but added: "We reserve final judgment until it becomes law."

However, Dr David King, the director of the campaign group Human Genetics Alert, which is strongly opposed to hybrid research, said: "Do not be fooled by the claim this is just research.

"Once we start down the path to GM babies, it will become very hard to turn back."

Q & A: ANIMAL-HUMAN HYBRIDS

What is a hybrid animal-human embryo?

Scientists take DNA from human cells and place it in animal eggs which have had most of their genetic material removed. Embryos grown from the eggs are more than 99 per cent human, with only a tiny animal component. Once the embryos have been grown in the lab - for no longer than 14 days - scientists can harvest stem cells for research.

Why do we need to use animal eggs anyway?

Ideally, scientists would collect stem cells from human eggs, but there is a severe shortage of such eggs, holding up research with the potential to help millions with serious diseases. Hybrid research allows scientists to use eggs from animals such as rabbits and cows, which are in plentiful supply.

Experts also believe that it is easier to collect stem cells from hybrid embryos.

Why will such research be useful?

Stem cells harvested from the hybrid embryos are a valuable resource, as they are the body's master cells, with the ability to develop into different tissue types.

Which conditions could be helped through hybrid embryo research?

Stem cell research could be helpful in finding treatments for a wide range of conditions, including serious illnesses such as Alzheimer's, Parkinson's, multiple sclerosis and motor neurone disease. Some also hope healthy stem cells could be implanted in humans to replace faulty cells and cure their illness.

Who is hoping to carry out research with hybrid embryos?

Two teams of British scientists, from London and Newcastle, have already sought permission to create animal-human hybrids for research. Professor Ian Wilmut, of Edinburgh University, had also been preparing his application for chimera research.

Why is hybrid research so controversial?

Some campaigners have questioned whether it is ethical to mix human and animal material.

Pro-life campaigners have opposed stem cell research because embryos are destroyed when the cells are harvested.