Despite humanity’s remarkable achievements as a species, reaching the apex of its capabilities, it seems highly improbable that our evolutionary journey has reached its conclusion.
The diverse factors contributing to our ongoing biological development, ranging from passive environmental influences to self-imposed pressures, are as captivating as they are varied.
Recent scientific inquiry has brought to light a previously unidentified mechanism by which inhabitants of the high-altitude Andes may be continuing to undergo evolutionary changes, driven by a surprisingly unassuming catalyst.
This particular demographic was among the earliest to cultivate the now-ubiquitous potato millennia ago, a historical association that may account for physiological evidence of an augmented capacity for starch assimilation.
“The elevated terrains of the Andes are recognized as a prolific milieu for comprehending human evolutionary adaptation, such as the response to hypoxia, a condition characterized by insufficient oxygen supply to tissues,” states anthropologist Abigail Bigham from the University of California, Los Angeles.
“This novel research underscores the significance of the Andes in elucidating human evolutionary adjustments to alternative selective environmental stressors, including dietary patterns.”
Evolution is a protracted process, contingent upon sustained exposure to a selective pressure, to which certain biological systems exhibit superior resilience compared to others.
These pressures can encompass extreme environmental conditions, including intense heat, complete oxygen deprivation, or hazardous radiation levels, as well as more subtle influences, such as the persistent low-level exposure to toxins or the prevailing food sources that populations depend upon.
Several years prior, a research consortium, including Bigham, observed that Indigenous communities residing in the Peruvian Andes appeared to possess genetic predispositions that facilitated starch digestion when contrasted with populations that incorporated potatoes into their diets more recently.
The research team has since broadened its investigation to encompass genetic data from across the globe, discovering that the Quechua people of highland Indigenous Andean heritage exhibit a remarkable aptitude for starch metabolism, surpassing nearly all other populations worldwide.
“For an extended period, biologists have hypothesized that distinct human groups have developed genetic adaptations in response to their dietary habits,” remarks evolutionary anthropologist Omer Gokcumen of the University at Buffalo. “However, instances with such compelling empirical support are exceedingly rare.”
The pivotal clue resides within a gene designated as AMY1, present in virtually all individuals globally. This gene plays a crucial role in the synthesis of salivary amylase, an enzyme instrumental in the initial stages of starch breakdown within the digestive system, commencing in the oral cavity.
Typically, individuals possess between 2 and 20 copies of this gene within each diploid cell; the global median, according to the findings of the recent study, stands at 7 copies.
Following an exhaustive analysis of the genomes of 3,723 individuals drawn from 85 distinct global populations, the researchers ascertained that Indigenous Quechua individuals from Peru exhibit a median of 10 copies of the AMY1 gene.
The researchers estimate that this genetic augmentation would have bestowed a survival or reproductive advantage of 1.24 percent per generation.
“Evolution operates akin to a sculptor shaping a masterpiece, rather than an architect constructing a edifice,” elucidates Gokcumen.
“It is not the case that Indigenous Andeans acquired additional AMY1 copies concurrently with the onset of potato consumption. Rather, individuals with a diminished number of gene copies were gradually phased out of the population over time, potentially due to reduced reproductive success, while those possessing a greater number of copies persisted.”
Employing genetic dating techniques and sophisticated modeling, the research team meticulously traced the emergence of this genetic alteration. Their dating methodologies indicated that the gene predated the domestication of potatoes, but its prevalence began to escalate approximately 10,000 years ago.
Historical records confirm that potato domestication in the Andes commenced between 10,000 and 6,000 years ago, a temporal alignment that corresponds with an increase in the quantity of copies of the gene that facilitates the assimilation of potatoes.
Conversely, other populations originating from the Maya lineage, which lack an extensive history of potato cultivation, do not exhibit the same augmentation.
Consequently, the observed temporal correlation is unlikely to be coincidental.
This outcome demonstrates the capacity for genetic adaptation to dietary shifts to occur within a relatively compressed timeframe, thereby introducing a nuanced perspective to the ongoing discourse surrounding the concept of the paleo diet.
Furthermore, certain scientific viewpoints strongly advocate that technological advancements are progressively emerging as the paramount driving force behind human evolution. This particular research offers an intriguing facet to that proposition.
In the not-too-distant past, dietary patterns were largely dictated by local availability. Presently, it has become commonplace to consume foodstuffs that are either directly imported or cultivated from imported progenitor species.
“Throughout the vast majority of human history, individuals subsisted on the same fare their ancestors had consumed for millennia. To alter one’s diet necessitated a literal migration across the globe. Therefore, what implications arise from our contemporary consumption of food sourced from every corner of the world?” poses evolutionary geneticist Kendra Scheer of the University at Buffalo.
“And now that we have empirically substantiated the role of natural selection in response to potato consumption, what are the ramifications given that the global population now consumes French fries?”
