Michael Pollan, writing in The Omnivore’s Dilemma, posits that instead of humans being the ones who conquered Earth, we should consider how plants and animals have colonized us. The obvious example is dogs. Did we domesticate them, turning them into docile, cute creatures? Or did dogs domesticate us, ingratiating themselves as “man’s best friend” in exchange for food and shelter? Corn is another example, which has survived and thrived in a human-dominated world, whereas other more delicate food-bearing plants have diminished and, in some cases, become extinct.
Alcohol is probably the most interesting example of this reverse colonization given our contradictory relationship with it. On the one hand, the rapid spread of genes for digesting alcohol rivals that of the genes for digesting lactose. On the other hand, one is considered an efficient delivery method for calories whereas the other is seen as a vice.
Most mammals have a minimal capacity to digest alcohol, and modern primates share some of our ADH (alcohol dehydrogenase) and ALDH (aldehyde dehydrogenase) genes. But around 10 million years ago, one of our ancestors came down from the trees and ate a piece of rotting fruit (was it the forbidden fruit?) without getting sick. That individual luckily had a mutation of ADH4 that was 40x more efficient than their cousin’s genes, thus expanding their and their descendants’ omnivorous diet.
But where things take off is around ten thousand years ago, right after the invention of alcohol distillation. It was then that humanity saw a rapid coevolution and dispersal of a handful of alcoholic genetic mutations (possibly coinciding with other 10,000 year explosions). There are now a handful of variations of the ALDH genes spread around different groups across the world, reflecting different histories with alcohol. For example, Peng, et. al, speculate that the “alcohol flush reaction” among East Asians coincides with the domestication of rice, acting as a protectant to curb overindulgence of rice wine.
Perhaps we don’t like to admit it, but alcohol is modernity’s number one sex facilitator. According to one study, one-fourth to one-half of emerging adults consumed alcohol before their most recent sexual occasion. If any feature becomes directly related to sex, the likelihood that it will spread throughout the gene pool increases exponentially.
Outside of sex, alcohol is ingrained into the way we socialize. Having an extra beer with a colleague could make the difference between a work promotion or career stagnation. During some periods of history, you could even get killed for saying the wrong toast.
The arrival of alcohol appears in retrospect as the perfect storm. It just so happens that hominids were accelerating in their usage of technology to expand their diet, the most significant of which is the invention of fire. But alcohol enhanced not only our dietary options but also our social and sexual ones. If we want to, we can choose to reduce our social inhibitions by merely taking a swill. If we feel like increasing the likelihood of having sex, we can visit a watering hole.
If the invention of knives coincides with the shrinking of human teeth, then does the invention of alcohol distillation coincide with the shrinking of our social and sexual skills? Pre-alcohol, did hominids have sober ways of yukking it up with friends and wandering into sexual entanglements?
I can’t think of another food-item that people love and hate as much as alcohol. Alcohol makes us vacillate between disgust and addiction. The resulting imprint on our genes is a war-torn battlefield reflecting our troubled past with it, and likely our future.