Thursday, July 07, 2005

William Hurlbut on Altered Nuclear Transfer

"Some have raised the objection that we may be just creating a 'disabled' embryo. This is a serious consideration, but I believe the recent proposal for ANT-OAR has fully met these concerns. This method would turn on certain master genes that define ES cells but which are never on in a fertilized egg. By fast-forwarding to the gene expression pattern of a pluripotent cell we would bypass the embryo and go directly to a differentiated cell type. A human embryo has a developmental potential; it is that stage at which the whole produces the parts. Without the capacities to form the basic body axes and body plan, a growing thing is simply not an organism, but merely a trajectory of disorganized growth. There is a proof in nature that you can get embryonic stem cells without an embryo. Naturally occurring ovarian tumors called teratomas can produce all the primary embryonic cell types and even more advanced tissues and body parts, but no physician would consider a teratoma a living being. Embryonic stem cells, likewise, lack the capacity to form an organism (they produce teratomas when implanted into the human body), so they too are not embryos. To be a human embryo means to have a coherent unity and a developmental potential along the trajectory of the human form. " (source)