South Korean scientists have succeeded in creating human embryo clones, a major breakthrough for the promising field of stem cell therapy – and for the far more controversial endeavor of cloning a human.
The achievement, to be published tomorrow in the journal Science, was hailed by many scientists because it brings closer the possibility that replacement tissues might one day be grown to treat medical conditions such as diabetes, spinal cord injuries and Parkinson’s disease.
The Korean authors were able to grow the embryos for several days and extract stem cells from one of them, then show these cells could turn into many types of tissues.
But the findings also demonstrate that there is no inherent block to using cloning technology to create babies that are genetic copies of pre-existing people. Indeed, the paper provides a recipe for the correct way of going about it.
Scientist and ethicists stressed that trying to make human baby clones would not only be ethically questionable but also unsafe. Studies on cloning in animals such as pigs and cows show that many of the embryo and fetus clones die because they contain tiny, genetic errors.
Experts in stem cells and cloning who had scrutinized the paper said that the findings appeared strong, in stark contrast to the high-profile but unsubstantiated reports of cloned babies and pregnancies that have cropped up over the past few years.
“It’s a stunning achievement, and I think it’s staggering that it has been accomplished so quickly,” said Gerald Schatten, professor of reproductive sciences at the University of Pittsburgh.
Cloning has been achieved in many animals since Dolly the sheep was born in 1996.
The Korean scientists conducted their experiment not to create human baby clones but to extract stem cells, which are capable of becoming many different types of tissues. To do so, they needed to grow embryos for only several days – up to the so-called blastocyst stage of embryo development.
Obtaining stem cells from clones is key because it offers the chance that people can receive tissue that is a perfect genetic match.