Flukes and Aberrations of the Human Body: a Chronological Misadventure

“Another Mikey took a knife
While arguing in traffic
Flipper died a natural death
He caught a nasty virus.”

Ah, the “wonders of the human body”! What manner of extramundane miracles emanate forth from its carbon-based quintessence! What thoughts, ideas, desires! What dexterous fingers and brilliant inventions, running speed, feats of strength, balance, heating, cooling! What….

What a load of crap.

The human body, as it is not a “product” resulting from a fabrication process, is nonetheless more machine than we may actually realize, mostly owing to the predictable molecular mechanisms underlying evolution and ontogeny.

It’s unlikely, however, that such a flawed “miraculous” entity would even make it past brainstorming, let alone quality control, in a major corporation. In fact, one could arguably make the case that the body’s current form is something of a temporary solution to a never-ending problem spanning more than 4 billion years on our planet: adaptation.

Disease resistance is just one of the aspects of human adaptation which has revealing flaws, particularly flaws that demonstrate just how much of life depends on the body’s own self-preservation mechanisms. Once you have kids, it’s not long before your “warranty is up”; your body stops compensating and every minor change presents bigger and bigger difficulties. The brain shrinks as unnecessary connections are not maintained (I won’t even go into the many problems that result from long term bipedal movement, which is inherently inefficient). You have programmed obsolescence.

Why do we age in the first place, one may very well ask?

After all, doesn’t the very existence of aging, explained as a way to avoid cancer (at least partially) mean that there was a flaw in the system in the first place? Not only is the answer “yes”, but one also can easily make cells immortal by adding excessive telomerase, which itself may be viral in evolutionary origin! This excited researchers at first, until they realized that unbounded cell division is an important first step in the development of cancer! Aging, on the other hand, is related to decreasing telomere length, thus halting cancer in its tracks (theoretically, but there are other, mutation-related, factors at play here).

Our understanding of death, mainly, may very well be important in understanding this issue properly. As the lyrics in the song suggest, does being killed by a virus constitute a natural death? When does one “die”? To answer this, we look to the brain, generally, but part of the answer to "how" may be found in the relationship that humans and viruses share; we saw the first clue above, where telomerase may have descended from a mammalian-integrated retrovirus.

The entire functional framework of our bodies depends on the correct translation of proteins from DNA molecules, an interaction mediated by RNA in various forms. Very few flaws in this system are required to confer either huge benefits, which slowly accrue in the long-run in the confines of a given ecosystem, or a sharp decline in functional protein product (misfolding), caused by mutations resulting from a number of sources; therefore, the body spends a large amount of time, using relatively precise transcriptional machinery, checking and rechecking to make sure that mutations are minimized.

Every once in a while, a lucky example of happenstance chromosomal fusing (or a possible beneficial mutation) demonstrates even more clearly the fact that accidents resulting in benefits do not an engineering marvel make. (I may discuss the RNA world hypothesis in another blog, as abiogenesis doesn't fit within the scope of this topic: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TCY-3WS6210-16&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=c9f64ba4908d1f76b491a31dfd466256)

Humans have one fewer pair of chromosomes than other great apes, with the, now confirmed, implication that fusion took place between two ape chromosomes in some common ancestor to form what now constitutes human chromosome 2 (http://www.citeulike.org/user/tkandell/article/456391).

Human mental decline also has potentially important evolutionary implications, and we’ve likely exacerbated the problem by lengthening our own life-spans considerably over the past century. One answer, suggested within the last couple of decades by scientists working on NMDA receptor function in rats, is that decreases in memory with age also decrease the ability of post-mating organisms to compete with younger ones for food sources.

Another possibility is simply that the preservation mechanisms needed to maintain proper mental function, i.e. avoiding the accumulation of harmful plaque-forming proteins and de-myelination, are only needed until such a time as offspring are conceived, cared for, and social obligations toward the larger group are met.

Returning to the definition of “death” issue, a basic examination of “brain death”, a look into case histories of those who have had hemispherectomies, as well as the strange post-ablation histories of HM, Phineas Gage, and other neural patients, reveals an unsettling breakdown in the very definition of “self” on which our species prides itself. Gage + 1 pipe through the frontal lobe= 1 shiny new personality, HM + surgical removal of the hippocampus = severe anterograde amnesia.

That is, when a part of the brain is removed, not surprisingly, a function is removed; that which confers our thought is divisible, and there is no “homunculus” residing in the brain that could be said to constitute “you”, despite the desire of Descartes for the soul to rest in the pineal gland.

Of course, thought experiments revealing the conflict between our understanding of the brain and body and “the self” can be easily tracked back to the time of Immanuel Kant (Descartes, Hume, Malebranche, Berkeley, and many others also dealt with this issue); the ever-changing nature of the physical body caused Kant to posit a “noumenal” soul unaffected by physicality. (Hilariously, this is a little self-defeating as, by definition, the noumenal soul cannot interact with the material world, meaning that whether it has any relation, even assuming it exists, to what we think of as “ourselves”, is doubtful.)

Such contradictions, though, are eliminated entirely when the mind is defined as “the activity of the brain”. However, this also has unfortunate implications for what “brain death” would, ultimately, mean to a species which prides itself in being worthy enough to survive the death of its corporeal components…

Given the human proclivity for consuming resources, our lack of predators, and the fever we’ve given our planet, a viral death like the one in the song underscores our close relationship with, and inherent susceptibility to, these protein-nucleic acid particles that have sunk their teeth directly into our DNA, forming a modern human identity closely tied to ancient weakness.

Given all of that, here's what I say:

If you’re going to be as incurable as the rest of us, why not try being an incurable optimist? I am, and I know one thing that improves one’s outlook on the previous, admittedly disheartening points: they underscore not our improvement, but our change- evolution ensures relevance, and we haven’t stopped doing that. (http://www.newscientist.com/article/mg18925421.300-are-we-still-evolving.html) You never know what primate dope will stab you while arguing in traffic...

Next week: Healthcare in America: We’re number 37! We’re number 37! Take that Slovenia!