ANT-OAR
altered nuclear transfer -- oocyte assisted reprogramming
Altered Nuclear Transfer (ANT) is a proposed technological approach to obtain human pluripotent stem cells, which are the functional equivalent of human embryonic stem cells, without creating or destroying human embryos.
ANT : http://alterednucleartransfer.com/ |
ANT
altered nuclear transfer (ANT) is a broad conceptual proposal for producing pluripotent stem cells without creating and destroying embryos... we outline a research program for a form of ANT that should allow us to produce pluripotent stem cells without creating or destroying human embryos and without producing an entity that undergoes or mimics embryonic development... oocyte assisted reprogrammingIncapable of being or becoming an embryo, the cell produced would itself be a pluripotent cell that could be cultured to establish a pluripotent stem cell line. Significantly, this cell would not be totipotent, as a zygote is.
The complete DNA sequence characteristic of the human species. Specifically, one-celled human embryos, pluripotent human embryonic stem (or ES) cells, multipotent human adult stem cells, and differentiated (specialized) adult human cells such as neurons all contain a complete human genome.
OAR
oocyte assisted reprogramming
ANT-OAR begins from the premise that the function and identity of human body cells are determined not by their genetics, but rather by what scientists call “epigenetics.” It is not the sequence of the more than 30,000 genes in the genome that determines whether the cell is a liver, cardiac or immune cell, since gene sequence is identical in nearly every cell in the human body — it is rather the programming of the gene sequence, or the cell’s epigenetic state.The epigenetic state of pluripotent stem cells is pluripotency, or the capacity of a cell to develop into nearly all the tissue types found in the human body. The epigenetic state of single-celled embryos is totipotency, or the capacity of a cell to develop all the tissues necessary for full human development in an organized and self-directed manner.
Using a procedure called somatic cell nuclear transfer, defenders of ANT-OAR propose extracting the nucleus of an adult body cell with its highly specified epigenetic state of the cell type from which it was extracted, such as a skin cell. This stem cell is then transferred into an egg cell whose nucleus has been removed. Without a nucleus, the egg cell is no longer an oocyte, or an egg cell, but rather an ooplast, an organic sac of oocyte cytoplasm.
Now — and this is crucial for the ANT-OAR proposal — before we transfer the somatic cell nucleus into the ooplast, we pre-emptively alter its epigenetic state so that the genes expressed in the nuclear genome are consistent with pluripotent stem cells and incompatible with a state of totipotency, and hence the existence of a human zygote.