By Adele Ardent Eden
September 4, 2017
I’ve been thinking about genetics quite a bit while surrounded by the heritage crops at La Villita—perhaps not surprisingly, as corn is one of the first model organisms used to scientifically study inheritance; each kernel visible on the cob is the genetically unique recipient of its own union and own history, as each kernel can have a different “father.” (This is especially visible on the Glass Gem variety, which looks as much like a coil of beaded necklace as a cob.) In my previous post , I mentioned how one human hand has the weight of the entire system of human civilization behind it—however, this isn’t just the weight of the current civilization, but historical civilization as well. As necessary, and as beautiful, as our domesticated food-plants are, they show the effects of generations of meddling, tinkering, and shaping. Humans diverted the ancestral plants from their niche in the ecosystem and bent them to human use; while traditional indigenous cultures have, more or less, found ways to exist in a relationship with vital non-human elements like maize (with some giving it spiritual weight comparable to that of their human forbearers) as a “western-civilization-based” human, I’ve struggled on this trip with finding a way to interact with the world that isn’t about absolute control...a way to allow place to shape me in turn.
I had to find a way toward understanding in a round-about way: through genetics, which is what I initially studied. There is one idea I keep coming back to, although it might be more familiar through genealogy than genetics: pedigree collapse (amusingly laid out here in great detail). We each have two parents, four grandparents, eight great-grandparents, sixteen great-grandparents...and if one follows this back far enough, say a little more than 30 generations, each person would have more people in his or her family tree than are alive on the earth at this moment. However, we are all the result of some inbreeding, so the family tree starts to collapse again as one looks back through time. If one traces their ancestry to a particular place, that individual may be related to everyone who lived in that region.
If you combine this with the fact that each person has only two “slots” for each gene (one inherited maternally and one paternally), it becomes clear that much of the genetic information—the instructions on how to make one particular version of a human being—available in your lineage was lost in getting to you: Of the 256 sets of potentially unique genes available to you in your specific set of great-great-great-great-great-grandparents, you only retained two copies. And the further back you go, the less you are genetically related to any one individual; in fact, because inheritance is random, and you aren’t allotted an equal amount of genetic material from all of your ancestors, your distant ancestors may have no genetic link to you at all.
Yet, if any one of these individuals had made different choices, taken a different path, you would not exist. And if genetic connection is not the arbiter of ancestry that we consider it to be, then the other humans, the plants, the animals, and the places that shaped “our ancestors” are then just as much our ancestors as the humans we find in our family tree: All the choices had to be made just so for the current world, for us, to exist. If this is so, control, then, must be a myth—our path is determined by the way itself and what is encountered there, rather than our own two feet, and we are being shaped as much as we shape—even if we are unaware of it. This also means that the places, plants, and animals that we invest our interactions in are as much the ancestors of far-future humanity as we may become.