Photo via Flickr / CC
There are always more people looking to receive organs than there are people looking to donate them, hence the international black market. Despite the scarcity, however, people still show signs of choosiness when considering just whose organs they’d want to let inside.
Consider the logic of the polyjuice potion from the Harry Potter series. By ingesting the potion, which contained a sample of another person’s bodily essence—perhaps DNA, though J.K. Rowling never made any explicit mention of nucleic acids—the drinker would adopt their appearance, down to every last detail.
This potion’s mechanism of action, reliant on DNA from another person, seems to have conformed to “essentialist thinking,” which maintains that “some internal, unseen essence or force determines the common outward appearances and behaviors” of something.
A recent study published in the journal Cognitive Science, from which the above definition comes, examined essentialist thinking in the context of participants’ attitudes when it came to accepting organ donations and blood transfusions from hypothetical donors with various personal characteristics.
Here's how it worked. Researchers at the University of Michigan presented potential organ recipients with a list of possible donors of various ages, genders, sexual orientations, and backgrounds. The list also contained people with mixtures of either "good" or "bad" qualities that were unrelated to the recipient. For example, some were said to be highly intelligent, gifted in the arts, or prone to philanthropy; others possible donors were said to be stupid, homeless, thieves, or murderers.
The donor’s possession of good qualities or bad qualities was a significant predictor of participants’ willingness to receive organs from them, with the repelling effect of the donors’ bad qualities holding more sway than the trust-building effect of the donors’ good qualities. Participants articulated fears that transplants from undesirable donors would contaminate them, and that they would somehow inherit the bad qualities to the detriment of their personalities and behavior. According to NPR, one patient ruminated that "the cruel murderer's qualities will come to me."
It was a perceived similarity to the recipients themselves, however, that seemed to most validate donors in the recipients’ eyes. Be they "good" or "bad," participants tended to skew toward those donors they perceived as being more like them.
One of the study’s lead authors, Meredith Meyer, suggests one possible explanation for the trend. "People dislike the prospect of any change in their essence—positive or negative," Meyer writes, "and so any salient difference between the donor and recipient leads to increased resistance to the transplant.”
Our preference--our tendency, really--to think of ourselves as being stable and consistent is a well-documented cognitive quirk. With increased recognition of phenomena like the “end of history illusion”, however, the evidence becomes increasingly compelling that we are always subject to change. What is still somewhat mysterious though is whether in confronting this reality we should also entertain the idea, as the participants of this study did, that other peoples’ bodily “essence” can impose this change on us.
Chimera. Via Wikimedia Commons.
In pondering the uncertainty, it might be worth examining chimerism. In ancient Greek mythology, a chimera was a hodgepodge beast cobbled together from the body parts of other non-mythological creatures. According to Wikipedia, a chimera is most often depicted “as a lion, with the head of a goat arising from its back, and a tail that ended in a snake's head.”
Modern biology has re-appropriated the word to refer to an organism that contains more than one group of genetically distinct cells. For example, a chimera might have some blood cells that are type A, and some that are type B. When one of the genomes in the mix is present only in isolated regions of the body, it is called microchimerism.
As it turns out, many mothers provide great examples of microchimerism, as a child's DNA can be present in its mother's body long after child birth. A 2012 PLoS One study involving post-mortem genetic analyses of the brain tissue of women who'd given birth to male children revealed Y chromosomes in 60 percent of the brains examined. Because normal female brain cell nuclei would contain two X chromosomes, and no Y chromosomes, the DNA was inarguably male. This means that the majority of women in the study had chimeric brain tissue. The researchers believe that the DNA entered their bodies from their erstwhile male fetuses through the placenta, eventually taking up shop in their brains.
It is not understood exactly why or how this instance of microchimerism occurs, or if it has any causal relationships with pathologies of any sort. However, the researchers from the PLoS One study did notice that of the women whose brains were analyzed, those who had suffered from Alzheimer’s disease contained less fetal-derived cells. This may suggest a direct or indirect protective mechanism of the chimeric cellular colonization.
In any case, the finding opens up the possibility that at least some aspects of our bodies, if maybe not the personalities that arise from them, can undergo change as a result of genetically dissimilar cellular presence. As such, it evokes the question of whether we should dismiss or look further into the “essentialist” instincts of the University of Michigan study participants.
The face transplant of Isabelle Dinoire.
Sure, some alleged cases of organ recipients claiming to have been affected by donor viscera come off as a bit of a stretch. But some cases are much less so.
Take Claire Sylvia, a mother of one who reportedly craved chicken and beer following a heart transplant from a young man who held a fondness for, you guessed it, chicken and beer. Sylvia wrote a book about the experience, though it's perhaps better suited for the lens of psychoanalyis rather than biology. On the other hand, Isabelle Dinoire’s claim that she began to grow a little facial hair after undergoing a partial face transplant--the first ever operation of its kind--seems easier to tackle.
The point here is there may be biological processes at work in organ transplantation, or other instances of genetic infiltration, that are so subtle as to be reliably discernable only through data analysis akin to that seen in the microchimeric brain study. Proving such phenomena could factor greatly into the interpretation of the essentialist sort of thinking exhibited by participants of the University of Michigan study. That the possibility hasn’t been ruled out only highlights the mystique of bodily chimerism and associated phenomena, even if “chimerism” still isn’t well known beyond Greek mythology.
As fun as it is to let that mythological flavor linger, or to swill fictional polyjuice cocktails, further research is still necessary, if only so we can know unequivocally that Dick Cheney didn’t get any nicer post-op.