There is a reason that centaurs and mermaids do not roam freely about the earth today; human-animal hybrids just don't work. Not only does human DNA not cooperate with animal DNA in order to form full grown chimeras, but a recent research effort demonstrates that empty animals' eggs can't even be used to clone human stem cells.
The idea sounds simple enough. Take a rabbit egg, empty it out, and use it as a home for human DNA to mature into a full-fledged embryo. After the resulting cells have grown and divided enough times, use the little cloned embryonic stem cells for treating certain difficult human diseases. Aside from the moral and ethical questions involved in mixing human and animal parts, it turns out it just doesn't work. Not as far as researchers had hoped, at least.
Researchers at Advanced Cell Technology, a Massachusetts-based company, recently published the results of their experiments in the journal Cloning and Stem Cells. They tried to clone human embryos through somatic cell nuclear transfer, the same technique used to clone Dolly the sheep and other animals since. Rather than using difficult-to-get human eggs, though, the researchers tried to use mouse, cow, and rabbit eggs. They thought that by taking an animal egg and removing the nucleus (and therefore the majority of the animal's DNA) they could reprogram the egg by filling it with the nucleus of a human cell. The efforts worked at first, but while the cells began to grow and divide, they quickly gave up. Using an animal's egg appears to turn off the genes that are needed to grow the cells into an embryo.
"For the last decade, we've carried out literally hundreds of experiments trying to create patient-specific stem cells using animal eggs," said Dr. Robert Lanza of Advanced Cell Technology. But, it never worked. "We never had the tools before to actually look inside the cell and see what's going on," Lanza said. Through a new method called global gene expression, Lanza's team was able to peek into the cell and watch the genes at work. What they saw told them it was unlikely an animal egg would be able to be reprogrammed by human DNA because the genes turned off when they were supposed to turn on.
For the record, cloning using human eggs hasn't worked either. While the correct genes do turn on in cloned human cells, the cells still stop dividing and give up before they develop into useable stem cells.
On the other hand, researchers have had success in treating diseases with the stem cells available in umbilical cord blood. Parents of newborns can pay to have their new baby's umbilical cord blood stored as a form of insurance against future disease. Private blood banks can charge 2000 dollars to process cord blood, along with an annual fee for storage, but some people believe the cost is worth it. Stem cells have been used to successfully treat leukemia and sickle cell anemia. The likelihood of a child's own blood being of help in the future is slim if the child's disease is genetic, but children have been treated with their siblings' cord blood. CBS reports that 12-year-old Brandyn Orr had leukemia as a young child, and chemotherapy did not beat it. When his younger brothers were born, their mother had the cord blood saved, and that blood was enough to give Brandyn a stem cell transplant. He's now healthy, and more research on stem cells from umbilical cord blood is being done to find ways to treat diabetes, heart failure, spinal cord injuries, and stroke.
Scientists may keep trying to reproduce human embryos using dubious methods, but it's both a morally questionable and unnecessary effort when stems cells are available through methods that do not require creating and destroying human embryos. If God programmed humans in such a way as to frustrate cloning, these scientists are just wasting their time.
"I will praise thee; for I am fearfully and wonderfully made: marvellous are thy works; and that my soul knoweth right well. My substance was not hid from thee, when I was made in secret, and curiously wrought in the lowest parts of the earth." -Psalm 139:14-15
