British biologists have received government approval to create the world's first human stem cells from hybrid embryos, part pig, part human.

The Warwick Medical School team, led by Justin St. John of the Clinical Sciences Research Institute, was granted the country's third animal-human embryo license from the Human Fertilisation and Embryology Authority, which goes into effect today (July 1).

The team plans to use a new technique that, if it works, could provide a well of human embryonic stem cells without the use of human embryos. They will fuse human adult skin cells into empty pig eggs, resulting in embryos with mostly human DNA and some pig mitochondrial DNA. Then, stem cells taken from the embryos will be chemically treated to destroy the pig DNA, which could impair cell function when interacting with human mitochondrial DNA.

The team plans to use skin cells from patients with mutations for heart disease, and hopes to grow the resulting stem cells into human heart cells. The stem cells will not be used to treat humans but to research genetic mutations. "Ultimately they will help us understand where some of the problems associated with these diseases arise," St. John told The Guardian. He cautioned that the research is expected to take considerable time.

Two previous licenses were granted for hybrid embryos to teams in Newcastle and London, however, the Warwick team is the first planning to create embryos free of animal DNA. The 12-month license is the first to be granted since the House of Commons voted in May in favor of the controversial research.