My fingernails won’t stop growing. In one week my intestinal lining will be completely turned over. New skin in one month. New blood in four months. New bones in ten years. Same teeth. Same neurons. Same eggs. Even my fingertip can (potentially) grow back as long as it’s cut off before the edge of the nail bed. There’s a lab in my building that grows brain organoids in dishes. This requires constant feeding of the brain organoid with oxygen so that the three-dimensional mass of tissue does not suffocate under its own weight and enter hypoxic conditions. They’ve recently begun to use our two-photon microscope which allows for high penetration of thick samples with high-powered infared excitation. The laser sits in a black foam box in the back of the room and staring into its beam will burn away your retinas in seconds. The brain lab, which studies torpor, is trying to put canisters of pure, highly flammable, oxygen into this room to feed their brain organoids with oxygen while they are being excited with lasers. This has been referred to by the building’s health and safety team as “risky” and “inadvisable”. My brain does fine though. It does not explode, even though I feed it with oxygen all the time. The brain is the greediest part of my body. It steals 20% of my body’s total oxygen. However I can stand next to open flames and usually not be at risk of spontaneous and explosive combustion.
In the central nervous system, neurons don’t renew, although the field of neuroscience is enterprising, dogged, and motivated by millions of dollars of regenerative medicine funding, at least in previous iterations of the NIH, so perhaps I speak too soon. In some ways the self is immutable. In some ways, I will never change except to degenerate. Neurons share fate markers1 with germ cells whose fate is egg/sperm then zygote then embryo then fetus which suggests that immortality can take different physiological forms. That fetus will have fingernails in ten weeks and those fingernails will keep growing. When my grandmother carried my mother in her womb, the fetus of my mother already carried the eggs that would one day be fertilized into the zygote that would develop into me. The genetic and environmental conditions of the grandmother in this way have transgenerational effects. In fruitflies, we call mutations “grandchildless” when they result in the ending of a grandmother’s lineage. The effects are not known until two generations have passed. It is easy to visualize these effects in fruitflies, which have a life cycle of ten days, although since I am eight years into studying one such grandchildless mutation, I can say that they are not easily understood. It is even more difficult to study these effects in mammals, let alone humans, who obviously live much longer. And that’s the argument fruitfly biologists make when they want to get funded by the NIH, at least by previous iterations of it.
Luis Aparicio was a shortstop in the MLB from 1956 to 1973 and is considered perhaps the greatest defensive shortstop who ever lived. In the book The Art of Fielding by Chad Harbach, a fictional version of Luis Aparicio has written a guidebook for shortstops. It advises:
“To field a ground ball must be considered a generous act and an act of comprehension. One moves not against the ball but with it. Bad fielders stab at the ball like an enemy. This is antagonism. The true fielder lets the path of the ball become his own path, thereby comprehending the ball and dissipating the self, which is the source of all suffering and poor defense.”
I’ve recently become very interested in the way people who love baseball write about baseball. It’s because baseball is so devoted to its own mythologizing. The baseball player in his most idealized form also seems to have a lot in common with the Sufi saint, subsuming his will to the path of the ball, rather than submerging himself in the divine, or truth, or love, or God, which under Sufism are all words for one meaning. To achieve a state of high alertness and also keen meditation, which is the path to ecstatic remembrance of divine/truth/love/God, the Sufi saint will sit with his forehead resting against one raised knee. All the better to consider and admire the gardens of the soul2. Do you think the batter standing poised at home plate, or the pitcher on the mound, feels this way too? Does he similarly have to discard the distractions of the external world to better admire the garden of the soul (baseball)????? Call me back ESPN.
Anyway. It’s impossible not to be marked. You still have to live in this world. You can’t perch your saintly forehead against your stupid knee forever. The pitcher has to step off the mound. You still have to suffer the world’s indignities, exploitations, pollutions, its distances, its magnificences. You carry more of the world than you think you carry. Between the years of 1955 and 1963, above-ground test explosions of nuclear weapons doubled the amount of carbon-14 in the atmosphere, allowing scientists to track the turnover of carbon in the world as well as in various organs and tissues of the human body. It’s because of this global transitory spike in a radioactive isotope that we know how fast your organs and tissues turnover. The lipids of your eyeball’s lenses3, for example, once having taken up that radioactive isotope, will keep that mark forever, as will the Achilles tendon and olfactory bulb neurons required for the sense of smell. They will not turnover. They do not regenerate.
Katja Heinemeier, the lead author on the study carbon dating the Achilles tendon, said to NPR, “What we see in the tendons [is] that they actually have a memory of the bomb pulse.” Developmental biology, being the study of change in a functional tissue4, is beginning to see instances of scars carried over from previous developmental stages into subsequent developmental stages. The body is in a constant state of remembrance, down to its tendons, even as its busy discovering its next form.
I wrote this newsletter to waste time in lab and make up more myths about baseball, and I’ve done that, so I’ll leave you with a few lines from Robert Farnsworth’s poem, “Night Game”:
“Nobody’s just watching, not those perched
on a billboard beyond the center-field fence,
nor the paid attendance, not the manager
thinking through his roster in the dugout,
slowly clapping. In the verdant block of light
carved out of evening, the game patiently
proceeds to discover its own dimensions.”
A lot can be said and, apparently, published, about fate markers and fate mapping, though none of it means much. I prefer to consider the poetic merits of fate markers rather than their biological merits, which in my opinion are few. I hate listening to sequencing seminars where the speaker talks like they’ve shaken god’s hand when what they’ve really done is spend hundreds of thousands of dollars to sort cells into arbitrary categories. I consider research like this garbage, and the machine learning algorithms (now referred to as AI in order to attract private funding) designed to parse through this garbage as ways to generate more garbage. Noise begets noise.
Busy with the study of the gardens of his soul, the Sufi saint in Rumi’s Mathnawi, Book IV, is beset by an interloper who tells him to stop sleeping, open his eyes, and appreciate the world’s material beauty. The saint replies, “His signs are in the heart, O man of
changeable desires. That (which is) external is nothing more (than) the sign of the signs." They should have told this to the Astros.In fact, humans appear to have lenses that are more resilient to the scourges of time than other mammals, containing more sphingomyelins. They also found sphingomyelins amongst the brain lipids of a 40,000 year old fossilized woolly mammoth. Fossilization is a way for one to bypass both regeneration and degeneration. Something to remember.
This is in opposition to cancer biology, which is the study of change in a dysfunctional tissue. Feels less imaginative, doesn’t it?