It's business as usual

 作者:胡母嫜傅     |      日期:2019-03-08 01:17:00
By Andy Coghlan WIDESPREAD derision greeted last week’s announcement by the British government that it is delaying its decision on whether to allow research into human cloning for “therapeutic” applications. In any case, the government’s precautionary approach may be undermined by loopholes in existing laws, New Scientist has discovered. Research on cloned cells and tissues can proceed legally in Britain, provided the cells are initially grown in laboratories abroad. Therapeutic cloning would use the technique that created Dolly the sheep to grow cells for transplants that are matched to their recipients—for instance to replace the brain cells lost in Parkinson’s disease. A donated human egg stripped of its chromosomes would be fused with one of the patient’s own cells to create an embryo. This would be allowed to grow for a few days until it forms a ball of cells called a blastocyst. From this, researchers would extract the embryonic stem cells that can, in theory, give rise to any of the body’s tissues (see Figure). Biologists now need to work out which of the growth factors that direct embryonic development will produce the desired cells. Therapeutic cloning is opposed by “pro-life” groups because it involves the destruction of an embryo. But research is already under way in the US, and in December the two committees that advise the British government on human genetics and embryology said that the law should be changed to allow therapeutic cloning in Britain while maintaining the ban on using the technique for human reproduction (This Week, 12 December 1998, p 5). Last week, however, the government announced that another six-month study would be needed before it would consider any such change. The decision has come under fire from scientists and many media commentators, with some arguing that the government is running scared of public opinion, following opposition to its policy on genetically modified food. “I’m disheartened,” says Martin Bobrow, a medical geneticist at the University of Cambridge. “They seem to have been bullied by a vociferous minority.” But the Human Fertilisation and Embryology Authority, which regulates embryo research in Britain, says that importing cloned embryonic stem cells would be perfectly legal. “Because they are not embryos, you wouldn’t need a licence from us,” says a spokesman. One company in Britain, Geron BioMed, is uniquely placed to pursue research into therapeutic cloning. The company, based at Roslin near Edinburgh, is licensed to use both the technique that made Dolly and methods of extracting stem cells. Its parent, Geron of Menlo Park, California, funds the research of James Thomson, a biologist at the University of Wisconsin. Last year, Thomson announced that he had isolated embryonic stem cells (This Week, 14 November 1998, p 6). Simon Best, managing director of Geron BioMed, told New Scientist that the company would consider making cloned stem cells available to British researchers. “If some of the British collaborators are the right people to do the work, we would certainly think about it,” he says. However, he points out that the cells are in very short supply,