Can a character have one kind of DNA in his semen and another in his blood?Yes—and it doesn’t require fantasy or magic. You’re describing a genetic chimera.
What is a chimera? In Greek mythology, this was a fire-breathing creature with the body of a lion, a goat’s head growing out of its back, and a tail comprised of a serpent.
Human chimeras are individuals with two distinct populations of cells. This can occur several different ways, but the most common is this:
Two separately fertilized ova start off as fraternal twins. Very early on, the two embryos fuse into a single individual, and the two sets of DNA are contained within that single individual. If chromosome set #1 produces the testicles and chromosome set #2 produces the blood or is responsible for the mucus membranes of the mouth (where a cheek swab for DNA is done), the two genetic profiles won’t match.
Chimeras occur more frequently in cases of in vitro fertilization.
Placental transfer of cells between mother and fetus can result in microchimerism—very small populations of genetically different cells in the mother or the fetus or both. The presence of fetal cells in the mother may have some connection to autoimmune disease (conditions in which the body perceives some of its own cells as foreign and attacks them).
Blood transfusion has been connected to microchimerism as well.
Most chimeras go through life without being discovered. The most popularized cases have been related to genetic matching for organ transplant and child custody.
Questions? Comments?
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Kelly has worked in the medical field for over twenty years, mainly at large medical centers. With experience in a variety of settings, chances are Kelly may have seen it.
Sometimes truth seems stranger than fiction in medicine, but accurate medicine in fiction is fabulous.
Find her fiction at www.kellywhitley.com.
Book blog: www.kellywhitleybooks.blogspot.com
