March 2, 2011
The latest issue of The Scientist has a profile of Rudolf Jaenisch of the Whitehead Institute (HT: THF). The piece mislabels as a "hit" claims of success at "therapeutic cloning", even though the hit was in reality a miss (or was actually a hit in terms of what one friend calls "Herodian cloning", involving reproductive cloning plus infanticide plus adult stem cell transplantation.) Jaenisch does have a lot of experience with nuclear transfer cloning as well as reprogramming of induced pluripotent stem (iPS) cells and generation of animals with both techniques. He and his co-workers have previously noted the rampant problems with cloning.
In this latest interview, Jaenisch makes more strong statements on nuclear transfer cloning in general:
In my view, you cannot make normal clones. Dolly looked normal. But after six years they had to kill her because she was so sick. Mice are the same. Most die very early [in development]. A few make it to birth. And the ones that survive look pretty nice for a year. But many die by 15 months. So I would argue that the animals that survive are just less abnormal than ones that die early. With nuclear transfer you never get normal embryos.
Regarding the uselessness of so-called "therapeutic cloning" (somatic cell nuclear transfer cloning, then destroying the young embryo to harvest its embryonic stem cells):
"Ten years ago, we talked about the potential of nuclear transfer for therapy. But it turns out the technique was of no practical relevance. You would never do it in humans for a number of reasons. First, its very inefficient. With mice, that doesnt matter because we can do hundreds of transfers to get a few mice. But human cloning is another order of magnitude more difficult than in mice. And people cant even get the eggs to practice [on]. My former student Kevin Eggan, along with his colleagues at Harvard, spent years putting in place a protocol to get volunteer egg donors. They spent a couple hundred thousand dollars just in advertising. And I think they got one or two donors. Kevins postdoc, Dieter Egli, who went to Columbia, told me that he got a couple [of] human nuclear transfers going, but they all arrested at the 6- or 8-cell stage. So theres something we dont understand going on in human [embryos]. It should work, but were not there yet.
Cloning proponents like Panos Zavos and Irving Weissman should take note.
Those interested in actual science-based treatments for patients should look at the successes of adult stem cells, in treating spinal cord injury, chronic heart failure, sickle cell anemia, multiple sclerosis, corneal blindness, and juvenile diabetes, to name a few examples.