Posted on 11/13/2003 6:24:42 PM PST by quidnunc
Our first clue to when is the different DNA identified oocytes in Jane’s ovary, and the different nuclear DNA found in various tissues of Jane’s body. Because Jane emerged as one whole neonate, without two belly buttons, we surmise that combining of Jane’s DNA and her twins DNA likely occurred following the formation of two different morula that combined shortly after hatching from separate zona pellucida that carried them to the mother’s uterus ... two ‘hatchlings’ combined into one blastocyst, with one placental organ sustaining one blastocystic cavity and one umbilical vesicle.
Using more technical terms, Jane is the result of two different sets of pluripotent stem cells that mixed very early in development. During a more generalized methylation process of stem cell cascading, some tissue lines from one genome cancelled out a duplicate construction process in the twin genome, so that organs of differing genetic blueprints developed alongside each other. Because Jane has her oocytes and a twin’s oocytes contained within her ovary—without the twin’s genome being identified by Jane’s immune system as ‘not me’—we may surmise that the direction of organ development allowed the chromosomes (on gene number 6) of both genomes to exist ‘peacefully’ in the construction of Jane’s immune system ... her twin’s cells have histocompatibility with her immune system, so her immune system recognizes the twin’s molecular marker identity as ‘also me’. Jane is the combination of her and her maternal twin, not an identical twin at fertilization.
A situation similar to Jane’s can occur if one twin donates an organ such as a kidney to its sibling … if the immune systems are a close enough match, the organ will not be rejected by the receiver of the organ donation and anti-rejection drugs will not be needed. [Such a close match is extremely rare unless the twins are identical; but if identical, the twins would have emerged from a single first zygote, and Jane is the merging of individual genomes from two separate zygotes because she has non-identical chromosomal DNA co-existing within her body. When we discuss human cloning, the tissue rejection issue will be central.] Jane’s transplantation process occurred at Jane’s earliest age in utero and involved many organ and tissue systems! Recall the wording from Dr. Jerome Lejeune regarding the early methylation of stem cells, from totipotent to pluripotent to multipotent: “... progressively at each division, this methylation is erased and replaced. And progressively cells learn by a cascade of reaction to specialize. So that one will make nails, another will make the brain, another will make the liver and another will make the bones and another will make the muscle.”
What makes Jane a chimera is the existence of two different genomes existing side-by-side in one functioning organism. At this point some will assert that ‘because Jane is the reality of two different genomes, then before the two genomes thoroughly combined, there were no individuals in embryonic state, just embryonic stem cells.’ We would reply that from the first division of cells by two separate zygotes in two separate zona pellucida, having two separate genomes from the same common father and mother, two individuals developed to the point where one was absorbed into the construction project for one vehicle of organs the once-separate then combined genomes accomplished. We would note also that the two sets of pluripotent stem cells worked in competition and in concert during the entire embryo age of Jane’s embryoid construction. Finally we would cite chimera individuals created through organ transplants.
The first thought that occurs with many reading the articles is, ‘what if the children had been born through in vitro fertilization’! Can you imagine the conundrum lawyers could have constructed from the situation, upon learning there is different nuclear DNA and mitochondrial DNA in the children than the woman who bore those children? And as legal appeals create legal precedent, imagine what the impact would be on criminal cases where DNA identification is used as evidence to convict or exonerate! It boggles the mind. How could a defense attorney or prosecutor ever explain enough basic biology and embryology for all the jurors to understand the possibilities? Without a jury of Embryologists, perhaps the prosecutor would present the biological facts and the defense attorney would then cite the exceptions. ... Or worse, the defense attorney would cite the facts and try to confuse the jury, only to leave the poor prosecutor at a loss to explain why the differences didn’t create reasonable doubt!
Does that mean she can sell one of them and still go to Heaven?
Using more technical terms...
Ya gotta love Free Republic. Where else does the guy start out with zona pellucidas and umbilicle vesicles, and then say, "Using more technical terms..."
I admit it, I read the whole thing. And I probably learned something, although I'm not sure what. I think it's that Jane is lucky to be alive and well-formed, because there were a lot of things that could have gone wrong there, but didn't. In any case, it's stuff like this that makes Free Republic great. No matter what happens, we have at least one expert on staff.
You said it! I could not agree more. However, I am not a biologist, so I am not sure my opinion counts here. :-)
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[Chimera-shift]
Hmmmm. I don't recall writing the above post. What's going on here?
Wonder if this is what accounts for hermaphrodites.
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