I often describe the blatant biased reporting about the ESCR debate. But much of the problem isn’t bias–it is ignorance. Say a general beat reporter is directed by his or her editor to do a stem cell story. He or she calls scientists–who may or may not mislead the reporter–and then writes a story that is often erroneous–not from bias, but because the reporter doesn’t understand what he or she is writing about. This story in the Philadelphia Inquirer, byline Marie McCullough, seems to be a case in point.
The story is purportedly about deriving ES cells without creating embryos. Hence, McCullough writes: Now, University of Pennsylvania researchers have stretched the definition [of an embryo] even further. In studies with mice, they created embryos using genetic material from only one parent–either a mother or a father. “In humans, this could provide a therapeutic route for both genders,” said senior author K. John McLaughlin, a researcher at the University of Pennsylvania’s New Bolton Center. “Members of either sex can use this technique to produce compatible stem cells, much like you might donate blood for your own use.”
For most people, the concept of a human “embryo” is straightforward: After a man’s sperm fertilizes a woman’s egg, it grows into a ball of cells that implants and develops in a woman’s uterus. But as animal cloning has shown, embryos can be created by replacing the nuclear DNA of an egg with the DNA of a body cell–say, a skin cell. No sperm needed.”
Uh, this is hardly news. It is called somatic cell nuclear transfer, a.k.a. cloning. And cloning does create an embryo. McCullough writes, no doubt because this is what she was told, that cloned embryos are “dead-ended,” and could not develop beyond the early embryo stage. But this isn’t at all clear. Cloned embryos certainly are not dead ended in animals. Remember Dolly?
McCullough then discusses what is known as parthenogenesis, a process which stimulates an egg to divide to the point where stem cells might be obtainable. She writes, “the human parthenogenetic embryos soon die because parts of their genetic code are unreadable.” But it isn’t at all clear that these divided eggs ever rise to the status of an organism. If they are not organisms, they are not embryos.
Finally, she discusses “androgenesis,” which I had not heard about before. The scientists also carried out the male version of parthenogenesis, called androgenesis. They removed the nuclear DNA from an egg and slipped in two sperm nuclei from a mouse. Two sperm nuclei were needed because, just as in humans, each sperm carries half the necessary genetic material.
This appears more akin to cloning than parthenogenesis. In any event, it would not create “tailor made” embryonic stem cells since the genetic makeup of the entities would not be identical to either sperm donor.
Most of this would seem to be way too impractical for therapeutic purposes.