"The same problems that arose with regard to ANT apply equally to ANT-OAR."

The ongoing debate about ANT-OAR may turn out to be fruitful not only for resolving this particular issue of bioethics, but also for reflecting on the fundamental questions concerning the beginnings of human life.

In this regard, I think that insufficient attention has been given to the view of Systems Biology that underlies the original proposal for ANT as presented by William Hurlbut (I will call this original proposal ANT-1).¹ This form of ANT consists, broadly, in nuclear transfer, but with the following modification: the Cdx2 gene (or some analogous gene) of the adult cell nucleus is switched off before the transfer. The effect of this modification is that after a few cell divisions the trophectoderm fails to form properly and the entity is incapable of developing further in a structured way.

ANT-OAR is another form of ANT. In normal SCNT, after the donor nucleus is introduced into the enucleated egg, the somatic cell nucleus undergoes a process of reprogramming. The nucleus is reprogrammed from a state of unipotency, which is proper to a somatic cell, to the totipotent state that is proper to the zygote. Now, in ANT-OAR the modification of the nucleus before the transfer consists in the forced expression of some of the factors that are associated with pluripotency. The goal of this is to force the process of reprogramming to result in the state of pluripotency, presumably without the new entity’s ever entering the state of totipotency. This procedure seems to avoid some of the problems associated with ANT-1, namely, that the product of ANT-1 shares some of the developmental stages of the embryo. This problem appeared to be overcome, thus allowing some early critics of ANT-1 to be able, now, to endorse ANT-OAR. As a result, the original proposal aside has been largely set aside and discussion has centered instead on ANT-OAR.

I think, however, that it is worth continuing the discussion around ANT-1 within the context of Systems Biology in order to clarify both the arguments presented by its supporters and the problems raised by its critics. In a second section I will show how this analysis proves useful for making a better judgment of ANT- OAR.

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