BioWorld International Correspondent

LONDON - The UK law on embryonic stem cell research is set to be further liberalized to allow the creation of animal/human hybrid embryos, in which the nucleus of an adult human cell is inserted into the enucleated egg of a mammal, such as a cow or rabbit.

In the introduction to the new Human Tissue and Embryos bill published last week, the government said it agrees in principle that the research into so-called interspecies embryos should be allowed. However, it stopped short of incorporating the measure in the bill, leaving it up to an all-parliamentary group that now will scrutinize the proposed legislation to decide whether to write the proposal into the bill.

At an earlier stage of preparing the bill, the government said it would ban all forms of hybrid embryo research, meaning the latest version is a victory of sorts for scientists and medical research charities that have campaigned for it to be allowed. But the draft bill does explicitly ban the creation of true hybrids that involve a fusion of animal and human gametes, leading to concerns that the move to allow interspecies embryos is not a sure thing.

Aisling Burnand, chief executive of the UK BioIndustry Association, said, "Despite government's acceptance in principle that legislation should allow the creation of hybrid embryos for research purposes, it is disappointing that this has not been included as a specific provision in the bill itself."

She added, "We call on the scrutiny committee to ensure that this research is permitted without delay by changing the draft clause in the bill."

The British Medical Association (BMA) voiced the same objection saying, "We urge the government to include the provision for this research in the bill itself."

The bill is designed to overhaul current law on in vitro fertilization and embryo research to reflect technological advances. Other measures include a total ban on sex-selection of IVF embryos for non-medical reasons and explicit rules on screening embryos for disease.

In addition, a new Regulatory Authority for Tissue and Embryos is proposed, which would replace two existing regulators, the Human Fertilisation and Embryology Authority and the Human Tissue Authority.

The BMA stood out against this change, too, saying a single body could not cover the range of subjects involved. "The complex and sensitive issues that surround reproduction and embryo research are very different from the equally complex and sensitive issues that relate to the retention and use of organs and tissues."

Two of the UK's stem cell research groups have applied for licenses to create interspecies embryos. Embryonic stem cell lines derived in this way would have no therapeutic applications but they could be used to generate disease-specific cell lines for use in drug discovery.

Doing the work also would enable researchers to refine and practice cloning techniques without using the scarce resource of human eggs.