What is Altered Nuclear Transfer?

By Robert F. Onder, M.D., J.D.

The embryo and cloning research debate in Missouri continues to get more complicated. Just when we thought we were getting the hang of terms such as stem cells, embryos, cloning, and SCNT, someone tosses “altered nuclear transfer” (ANT) into the debate. Specifically, some have argued that while human embryonic stem cell (ESC) and cloning (SCNT) research are immoral because they require that human embryos be killed, ANT is moral because it produces stem cells without first creating and killing human embryos. Others argue that ANT produces a defective embryo, one with a fatal genetic abnormality but nonetheless an embryo. This article will explain what ANT is and briefly discuss the ethics of this new technique. Regardless of one’s position on the morality of ANT, all pro-life voters should oppose the so-called “Stem Cell Research and Cures Initiative” because it creates a right to clone and kill human embryos, kill embryos from fertility clinics, and would require Missouri taxpayers to foot the bill.

Stem Cells, Embryos, and Cloning
To understand the moral debate over ANT it is important to first understand the debate surrounding embryo research, cloning, and stem cell research. Readers of the Metro Voice are likely to be familiar with these terms, but a brief review is appropriate here.

First, what are stem cells? Stem cells are very early precursors of other cell types. When cells are damaged in our bodies, stem cells can change into the type of cell that needs to be replaced. There are stem cells in every tissue in the human body including blood, bone marrow, brain, liver, fat, baby teeth, and umbilical cord blood. These cells are known as “adult stem cells” (ASCs). Another type of stem cell is the “embryonic stem cell” (ESC). Embryonic stem cells are derived from five to seven-day old human embryos. These embryos can be created by fertilization or by cloning (also known as “somatic cell nuclear transfer” or SCNT). ESC research using either kind of embryo is immoral because it requires killing these very young human beings to obtain their stem cells.

How do scientists clone embryos? Embryos are cloned by a process known as “somatic cell nuclear transfer” (SCNT). First, the genetic material or nucleus is removed from an egg. Then the nucleus of a somatic cell (body cell) is transferred into the enucleated egg. In the case of human cloning this would produce an egg that had been fertilized with the 46 chromosomes from a body cell, forming a single cell human embryo. This cell would then divide into 2, then 4, then 8, then 16 cells, and so on, just like any other embryo. Cloning researchers would like to “harvest” these tiny babies at five to seven days of life in order to obtain his or her stem cells. This of course is morally wrong because the intentional destruction of innocent human life is always wrong. Well-meaning scientists and ethicists have therefore sought ways of producing embryo-like stem cells without first creating and killing human embryos.

What is Altered Nuclear Transfer (ANT)?

In 2004 William Hurlbut, an ethicist on the President’s Council on Bioethics, proposed ANT as an ethical way to obtain embryo-like stem cells. Hurlbut, himself pro-life, agrees that ESC and cloning research are wrong because they involve the creation and destruction of human embryos. He proposed that ANT would be a way to create embryo-like stem cells without the intermediate step of creating an embryo.

ANT in many ways resembles SCNT, in that both require that a somatic (body) cell nucleus be transferred into an enucleated egg. The difference is that in ANT the scientist first removes a gene in the somatic cell prior to transfer. Without the deleted gene, the cell created when the somatic cell nucleus is transferred can only develop so far and then it will die. Hurlbut argues that since the cell created by ANT does not have the potential to undergo full embryologic development, it has no chance of ever developing into an older embryo, fetus, or baby, and therefore it should not be considered to be “human life.”

One group of scientists, Meissner and Jaenisch, actually performed Hurlbut’s experiment using mice. They began by removing the CDX-2 gene (the gene that is necessary for the development of the trophoblast – the part of the embryo that becomes the placenta) from a somatic or body cell nucleus. This altered nucleus was then transferred to an enucleated egg, just as in SCNT. Then the cell began to develop just like a normal embryo, until it reached the point where the CDX-2 gene was needed. Lacking the CDX-2 gene, no trophoblast was formed, but they were able to harvest stem cells from the embryo and establish a stem cell line. Hurlbut would argue that in this experiment no embryo was ever created by this procedure, and therefore ANT was used to obtain stem cells in an ethical way.

Other ethicists, including myself, are not so sure. They argue that ANT does indeed create an embryo, albeit an embryo with a fatal genetic defect. ANT, they argue, produces an embryo designed to die at a very early stage. They point out that the cell produced by ANT goes about doing exactly what embryos do, dividing into 2, then 4, then 8, then 16 cells, and so on. This new entity does just fine until the point in early development when it needs the CDX-2 gene. To these ethicists it would be as if a scientist engineered an embryo with the genes responsible for lung development removed. Since babies do not need lungs until they are born and have to breath air, they would go along and develop and be born at nine months of pregnancy. Then they would die for lack of lungs. These babies would have no potential to survive through infancy; therefore they will never go on to become older children or adults. Nevertheless, they are human beings, just like babies who are completely healthy. We would say they are babies with a fatal genetic defect; we would not say they are not babies.

I believe that the latter analysis is the correct one. I respect Dr. Hurlbut’s attempt to fashion a compromise that will enable scientist to obtain embryo-like stem cells without killing embryos. We cannot escape the fact, however, that this technology creates an embryo that is otherwise just like any other embryo, except that it has been engineered to die of its genetic defect. I therefore do not believe that Hurlbut’s proposal accomplishes what he sought to do.

Another problem, I believe, with promoting ANT as an alternative to cloning (SCNT) is that it involves admitting a point that I am not at all ready to concede to the pro-cloners: that somehow embryonic stem cells are better than adult stem cells. I have spoken and written on this topic extensively, and there is absolutely no evidence that this is the case. There have been over 65 treatments with adult stem cells, as opposed to none with embryonic stem cells, and there are numerous disadvantages to ESCs (tumor formation, genetic instability, etc.). Rather than debating ANT, which one critic has called a “sideshow,” we ought to be actively pursuing the much more promising and ethical option of adult stem cell therapy.

Finally, promoting ANT does not represent an alternative to a comprehensive ban on human cloning. All pro-life Missourians should work to oppose the grossly immoral “Stem Cell Research and Cures Initiative” which would enshrine the right to clone and kill human embryos in the Missouri Constitution. For more information on pro-life efforts to defeat this Initiative, please visit www.nocloning.org.

Robert F. Onder, M.D., J.D. is an Assistant Professor of Clinical Medicine at Washington University School of Medicine in St. Louis, MO. He is also on the board of directors for Missourians Against Human Cloning and a Republican candidate in the upcoming August 8th primary election for the Missouri House of Representatives District 13 (Lake St. Louis and Wentzville). For more information regarding Missourians Against Human Cloning visit their web site at www.nocloning.com. For information regarding Dr. Onder’s campaign call 636-561-8968 or visit www.bobonder.com.