Bioengineering, prehistory and futurology

John Hawks has an entertaining piece on Slate.com about the prospects for bioengineering a more sustainable humanity.

But hunting big animals to extinction was not the only option. People in Mesopotamia, China, Mexico, and other places invented a new ecology, depending on more sustainable rabbits, birds, and shellfish. They collected grains so intensively that the grasses began to rely on us to disperse and plant them.

These were the first farmers, staying in one place to plant and harvest. Some groups began to domesticate animals and then to milk them. Switching from hunting to a sedentary farming lifestyle generated more calories with fewer carbon emissions, because milk is much more efficient than meat. They weren’t worried about atmospheric greenhouse gases, of course, but their new lifestyle allowed for a more efficient use of Earth’s natural resources.

What do these lifestyle changes have to do with genetic engineering? They wouldn’t have been possible without modifications to human biology. Prehistoric children naturally lost the ability to digest lactose, or milk sugar, as they got older. So in order to create a culture of dairying, which allows for a reduction in meat intake, our ancestors had to undergo some kind of genetic mutation—one that allowed them to consume lactose throughout their lives. We’ve now identified five versions of this shift in the human genome. That means there were five milky X-Men born less than 10,000 years ago, and who today have hundreds of millions of descendants around the world.

Few topics so easily generate discussion in undergraduates than evolution and futurology. What does evolution suggest about the future of our species and the planet? Are we getting smarter? bigger? more prone to heart disease? Is evolution the reason why, or is it simply the by-product of human society?

John takes an interesting tact on futurology by looking at the present as the future of the past…we are the future humanity shaped by the actions of our Holocene ancestors. Adult lactose tolerance is common in a large number of human populations because the consumption of milk-based food products ended up being a pretty efficient way to feed a population in a given environment several thousand years ago. This in turn created conditions whereby individuals able to effectively utilize milk-based food (and the genes they carried with them that enabled this) were selectively favored and became more frequent. It also helped that the transition to a sedentary, agriculturally based ecology, while producing quite a few negative health outcomes, allowed for a pretty massive expansion in overall population size. Life may very well have been pretty bleak from a health perspective for early farmers, but they were definitely having children at a greater rate than their hunter-gatherer ancestors. The combination of a changing selection environment and more fuel for natural selection to act, in the form of novel mutations (we all carry a couple hundred of them), create an evolutionary feedback cycle that has made those of us living today quite different, at least in our internal workings, than our recent Holocene ancestors.

So John’s argument, on the issue of bioengineering our way to a better future, is that we have already done it. And we did it without trying, because evolution is at least in part shaped by what we do. John does not make the argument, common in anthropology and the eugenics movement in the early 20th century, that modern society is somehow “wrong” or “harmful” from an evolutionary perspective. My favorite example of this comes from the famous Harvard anthropologist, Earnest Hooton, in his 1939 book The Twilight of Man, from a chapter entitled “The Wages of Biological Sin”:

First of all, we have that delicately adjusted, upright spine with its dangerous lumbar curve. Even before the infantile vertebrae are completely transformed from cartilage to bone, we begin to prop up the babies in a sitting posture which is likely to distort that plastic spine. Soon we thrust them into schools where they sit for hours acquiring rudimentary scholarship and advanced scoliosis, or lateral curvature of the spine. Meanwhile the shoulders are hunched, the chest contracted, and the organs of vision strained by premature concentration upon the dubious wisdom of the printed word. The mysterious human predisposition to specialized use of the right hand is exaggerated into a physiological abnormality, and bilateral asymmetry advances to the threshold of deformity. The human foot is so radically modified for support and locomotion that it requires optimum physiological utilization if it is do its work at all. Straightaway we encase this delicate organ in rigid, ill-fitting shoes which cramp it, distort the already vestigial toes, and by artificial support destroy the strength of the makeshift arches which have been bestowed by a casual heredity. Then we lay hard and inelastic pavements and floors upon which the imprisoned feet are condemned to stand and walk during the remainder of their unnatural life. Before the child has cut his first permanent tooth, he is ripe for the ministrations of the orthopedist, because his spinal curves are askew, his foot arches flattened, and the entire muscular tone, essential for proper maintenance of the erect posture and for bipedal progression, has been destroyed. Then we cap the climax by substituting for the ordinary animal method of locomotion the conveyance of a stinking mechanical contraption, which more than any other invention of modern civilization is responsible for bodily and mental atrophy, the breakdown of social organization, and the decay of public and private morals. It is not strange that unaccustomed strains or movements of the body result in sacroiliac slips and other joint difficulties when the flabby automobile addict attempts to indulge in exercise.” (p. 295-296)

It goes on from there…This is not the argument that John makes. Nor does John actually say we shouldn’t think about the ways in which our actions may impact the future evolutionary environment of the world. For example, we know that current practices in utilizing anti-biotics, particularly in large-scale livestock production, but also in the context of developing world settings where the drugs are expensive, have created a selective environment which encourages the survival of more drug-resistant strains. This is something that we have the knowledge to understand, but have a pretty hard time changing. I am not very interested in ideas about making humans better in some specified way, but I do think we should use the knowledge we do have to think about how we are impacting the evolutionary trajectory of the world around us.

About Adam Van Arsdale

I am biological anthropologist with a specialization in paleoanthropology. My research focuses on the pattern of evolutionary change in humans over the past two million years, with an emphasis on the early evolution and dispersal of our genus, Homo. My work spans a number of areas including comparative anatomy, genetics and demography.
This entry was posted in Evolution and tagged , . Bookmark the permalink.