July 29, 2008
Back in November of 2007, Ian Wilmut, cloner of Dolly the sheep, announced his intention to give up on cloning and instead focus on the new technique of induced pluripotent stem (iPS) cells developed by Shinya Yamanaka of Japan. Yamanaka's technique "reprograms" ordinary cells such as skin cells back to an embryonic state where they have characteristics similar to embryonic stem cells, but the technique does not use embryos, eggs, or cloning (somatic cell nuclear transfer). In fact, Yamanaka never used any human eggs or embryos in developing the technique, only mouse. The reprogramming technique is also much easier to accomplish than cloning. In it's August 2008 issue, Scientific American has published an article (originally titled "No More Cloning Around") and an interview with Wilmut on his reasons for the switch in research direction. (Tony Perkins, President of Family Research Council, is quoted in the news article.)
The article notes that "practicalities... seem to be driving the SCNT exodus," and "It is hard to escape the sense that SCNT research is on the wane. The ethical barriers and short egg supply remain daunting." Not to mention the technical problems (it doesn't work well at all, and is horribly inefficient; as noted by many scientists, including Wilmut in the article.) Bottom line: Wilmut has given up on cloning for practical reasons.
Still, there is an interesting discussion in the Wilmut interview about the possibility of using cloning to produce an embryo with its genetic defects corrected. What he actually describes is Embryo Cell Nuclear Transfer (ECNT). An embryo is first created by fertilization, one of the cells of this original embryo is genetically altered to correct whatever might be the problem, and then the nucleus of this embryo cell is transferred into an enucleated egg, to produce a new, cloned embryo. Wilmut doesn't seem to have any problem with this.
This is what some have described as creating 3-parent embryos. But it's still cloning.