First cloned human embryos

Scientists in the US announced yesterday that they had created a cloned human embryo for the first time. Their work was part of research into therapeutic cloning - creating cells or tissue for transplant from a person's own cloned embryo and subsequently lessening the risk of rejection. The research team also report that they made unfertilised human eggs to behave as though they were embryos, though a process known as parthenogenesis. The peer-reviewed research was published today in the Journal of Regenerative Medicine.

The researchers at Advanced Cell Technology (ACT), a biotechnology company in Massachusetts, used the so-called Dolly technique to produce three human embryos. The technique involved the removal of the nuclei from human eggs and the replacement of them with the nuclei of adult skin cells. The research paper reports that the 'somatic nuclei showed evidence of reprogramming to an embryonic state'. When the news of the embryos broke, they had each only reached the six-cell stage. ACT's ethical guidelines prevent the embryos being kept for more than 14 days.

Robert Lanza, one of the ACT scientists involved in the cloning project, said that 'the work sets the stage for human therapeutic cloning as a potentially limitless source of immune-compatible cells for tissue engineering'. He added that ACT's intentions were 'not to create cloned human beings but rather to make life-saving therapies for a wide range of human diseases including diabetes, strokes, cancer and neurodegenerative diseases such as Parkinson's and Alzheimer's'.