Posted by: Winslie Gomez | 27/03/2008

Humanimal Embryo Frankenbunnies or Rational?

 Cloning expert calls on MPs to back hybrid embryos work

A LEADING stem-cell researcher yesterday joined calls for MPs to support potentially life-saving work using animal-human hybrid embryos.

Sir Ian Wilmut, who led the team which created the clone Dolly the sheep, said he respected the views of religious figures such as Cardinal Keith O’Brien, the leader of the Catholic Church in Scotland, who has condemned the use of animal-human embryos in research.

Scotsman 27 March ’08

The Why, What, Who etc of the human-animal embryo research.   Edited version offered here.  Please read the full report which explains the rationale behind the arguments for and against.


Why are human-animal embryos in the news?

Two groups of UK scientists have today won approval to create human-animal embryos for medical research.

The long-running issue of whether to allow production of the embryos – using human DNA implanted into animal eggs – has in the past prompted sensational headlines about “Frankenbunnies”. A government white paper published in December 2006 after public consultation originally announced that the creation of chimeras – organisms consisting of at least two genetically different kinds of tissue – and other kinds of interspecies embryos would be banned.

What is a human-animal embryo?

True hybrid embryos are made by fertilising an egg with the sperm of another closely related species; for example, a mule is the offspring of a donkey and a horse. Chimeric embryos are made by injecting cells or genetic material from one species into the embryo of another. Scientists at Stanford University in California plan to use this technique to create a mouse with 10% human brain cells. The third type are human transgenic embryos, made by injecting a segment of animal DNA into a human egg.

The fourth type is a cytoplasmic hybrid and is the one being developed in British universities. It is created by transferring the nuclei of human cells, such as skin cells, into animal eggs from which almost all the genetic information has been removed. The resulting embryo would contain only a tiny amount of animal DNA – around 0.1% – and the rest would be human. The embryo would be grown in a lab to a size of around 200 cells.

Why create human-animal embryos?

Scientists developing these embryos say they will provide a plentiful source of stem cells – immature cells that can develop into many different types of tissue – for use in medical research. Researchers believe that by producing stem cells carrying the genetic defects of diseases they will be able to work out how a cell’s molecular machinery goes awry, and perhaps find new cures for diseases.

The research has been hampered by the severe shortage of “spare” human eggs donated by couples undergoing fertility treatment. By using animal eggs, which are far more readily available, British research teams hope to make more rapid progress. Their experiments have shown that the stem cells harvested from hybrid and chimeric embryos behave identically to human ones.

Who is trying to create them?

A team led by Professor Stephen Minger, director of the stem cell biology laboratory at King’s College London, has been offered a licence by the HFEA to use human-bovine embryos to study degenerative neurological diseases such as Parkinson’s and Alzheimer’s. Dr Lyle Armstrong, of the Northeast England Stem Cell Institute, Newcastle University, has been offered a licence to use cow eggs to research replacement tissues for treating conditions such as diabetes and spinal paralysis.

A third team led by Professor Ian Wilmut, the Edinburgh-based creator of the first cloned mammal, Dolly the sheep, wants to create human-rabbit embryos to develop treatments for motor neurone disease, although it has yet to apply for a licence.

What happens next?

The research teams at King’s College and Newcastle have to formally accept the offer of the licences.

What are the objections?

There were 300 responses to the government consultation, with 277 opposed to the research, many of them from pro-life groups opposed to any research on embryos. But not all opposition is religious or ethical. Some scientists are also sceptical about the research.

Professor Sir John Gurdon, a Cambridge University researcher who has injected human DNA into frogs’ eggs, told the paper: “Scientifically … I’m not persuaded it will work. If you put cells from one species into the egg of another, the egg may divide, but you could get a lot of genetic abnormality that won’t lead to good-quality stem cells.”

What does the law say?

Ministers originally said they would like to outlaw the creation of human-animal embryos. A 2006 white paper to overhaul the Human Fertilisation and Embryology Act 1990 proposed banning hybrid work. But the draft fertility bill, published in May 2007, includes a regulation-making power that could lead to human-animal hybrids being allowed. Under existing law, hybrid embryos could not legally be implanted into a woman’s womb.

What is the situation in other countries?

Chinese scientists were reportedly the first to successfully create human-animal embryos. In 2003 a team at the Shanghai Second Medical University fused human cells with rabbit eggs. The embryos were allowed to develop for several days in a laboratory dish before being destroyed to harvest their stem cells. Later that same year, US scientist Professor Panayiotis Zavos announced he had created “human-cow” embryos that lived for around a fortnight and could theoretically have been implanted into a woman’s womb.

In 2004 researchers at the Mayo Clinic in Minnesota produced pigs with hybrid pig-human blood cells. In 2005 Parkinson’s disease researchers at the Salk Institute in San Diego reported they had created mice with 0.01% human cells by injecting about 100,000 human embryonic stem cells per mouse. Last year Yale researcher Eugene Redmond led a project injecting millions of human neural stem cells into the brains of monkeys afflicted with Parkinson’s disease. Many countries have banned this human-animal embryo research, including Australia, Canada, France, Germany and Italy.

Article in Guardian
Img thanks to



  1. […] by religious doctors that commends the support of Muslims and Christian joining forces against the Embryo Bill that Gordon Brown, our UK Prime Minister is being slated in the […]

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