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Banning Stem Cell Research -- Or Cloning? Or Both?

A front-page article in the Minneapolis StarTribune entitled “Stakes High In Cloning Debate” (March 30, 2011) discusses a bill recently introduced into the Minnesota legislature to criminalize “human cloning.” The article reflects on the confusion surrounding what it is, exactly, that groups like “Minnesota Citizens Concerned for Life” want to ban. Put another way, they think they know what they want to ban, but they don’t know how to describe the science they are demonizing. For example:

“In adult stem cell research money is flowing like a river,” Scott Fischbach said, “[In contrast], money going into embryonic stem cell research is resulting in nothing but dead embryos.”

Very charged language, but it has nothing to do with human cloning per se. The real purpose of the bill is not to ban the cloning of a human being—which the sponsors surely want to accomplish as well — but to block research involving the “destruction of human embryos”, whether or not they could develop into cloned babies. Let’s recap. Dolly, the cloned sheep, was “produced” by removing the nucleus from an unfertilized ewe’s egg (an “oocyte”), replacing it with nuclear material from an adult cell of a different sheep, inducing the reconstituted egg to divide with an electrical pulse, and reimplanting it in the ewe from which the egg was taken. Eventually, Dolly was born—a clone of the sheep that provided the “replacement nucleus”. The mother ewe was the surrogate, not a genetic parent.

A simple claim to this process appears in Roslin Institute’s PCT WO 97/07669:

“An animal prepared by a method comprising:

(a)    reconstituting an animal embryo by transferring the nucleus of a quiescent adult somatic cell into an enucleate oocyte;

(b)   causing an animal to develop to term from the embryo; and

(c)    optionally, breeding from the animal so formed.”

Now substitute “human” for animal, and you get the kind of process that you might think the bill banning cloning is intended to prevent and indeed, it would. “The U emphasizes that it has not and will not attempt to clone a human being, a process called reproductive cloning,” reports the article. As an aside, it is ironic that a group concerned with preserving human life would want to ban a process that theoretically could permit couples unable to have children to conceive, albeit a clone of the mother or the father.

However, the primary thrust of such bills is almost always to prevent the destruction of human embryos, not simply to ban cloning which, as I have just noted creates viable embryos, and ultimately, living beings. There are two main routes that researchers use to make “embryonic stem cells”.  The first involves using fertilized eggs such as the ones prepared during in vitro fertilization procedures, but discarded once pregnancy is achieved. A few hours after fertilization, the cellular mass is termed a blastocyst. Physical disassembly of the blastocyst, and cultivation of the cells yields stem cells that can be induced to form a wide variety, if not all, types of human tissue. The cells may or may not “match” a recipient and be useful for therapy. This process is the one that could be funded under the recently issued executive order from President Obama. This process was first developed by WARF, and is claimed in the controversial Thomson patents. (See claim 9 of U.S. Pat. No. 6200806).

“Therapeutic cloning” is more interesting, and more controversial. In that procedure, the nucleus of an unfertilized egg from any human donor would be removed (a la Dolly) and replaced with nuclear material from the human patient, e.g. a type I diabetic. The reconstituted egg would be induced to divide to form an embryo that would be an almost perfect genetic twin of the patient. However, the embryo would not be permitted to develop to term, which would result in a cloned human (a genetic twin of the patient).  Stem cells would be taken from the early stage embryo and induced to form, in this case, pancreatic islet cells, would be a match with the patient, and could potentially be used to cure his/her diabetes. Theoretically, any genetic defects in the stem cells could be repaired before the cells are implanted into the patient.

As drafted, the bills presently working their way through the Minnesota legislature would ban “therapeutic cloning” but permit the production of embryonic stem cell lines from embryos produced by in vitro fertilization.

For more information visit the Stem Cell Action newsletter.

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