Academic Reading: 2

The Domestication of Wheat and the Origins of Agriculture

For much of the twentieth century, historians and archaeologists tended to describe the shift from foraging to farming as a single transformative moment sometimes called the Neolithic Revolution, as though early humans in the Fertile Crescent had abruptly decided, at some identifiable point roughly ten thousand years ago, to abandon hunting and gathering in favor of cultivating wheat and other cereal crops. Genetic and archaeological research conducted over the past several decades has substantially complicated this picture, revealing domestication as a far more gradual and, in some respects, accidental process than the term "revolution" implies.

Central to this revised understanding is a single, well-documented genetic trait: the non-shattering rachis. In wild wheat, the rachis, the small structure connecting each seed to the main stalk, is naturally brittle and breaks apart easily once the seeds ripen, scattering them across the ground so that new plants can grow the following season. This trait, clearly advantageous for a wild plant reproducing without human assistance, becomes a serious disadvantage the moment humans begin systematically harvesting wheat, since scattered seeds cannot be collected efficiently. Occasionally, however, a mutation arises that produces a tougher, non-shattering rachis, which keeps seeds attached to the stalk even after ripening. In the wild, this mutation would typically be an evolutionary dead end, since a plant unable to scatter its own seeds would struggle to reproduce naturally. Once humans began deliberately harvesting and replanting seeds, though, the mutation became a significant advantage: non-shattering plants were, quite simply, easier to harvest and thus more likely to have their seeds collected and resown by human cultivators the following year.

Archaeological excavations at sites across the Fertile Crescent, in present-day parts of Turkey, Syria, and Iraq, show that the proportion of non-shattering wheat found in preserved plant remains increased only gradually over a period that some researchers estimate at several centuries, rather than appearing suddenly in a single generation. This gradual timeline suggests that early cultivators were, in an important sense, unintentionally selectively breeding wheat for years or generations before the plant became fully domesticated in the form we would recognize today, blurring the line between simply gathering wild plants and deliberately farming domesticated ones.

The consequences of this transition, once it was largely complete, were profound but decidedly mixed for the humans involved. Skeletal remains from early farming communities frequently show evidence of nutritional stress, including reduced average height and increased dental problems, compared with skeletal remains from earlier foraging populations, likely reflecting a diet that, while more reliable and abundant in calories, was also considerably less varied than a forager's diet of wild plants, game, and fish. At the same time, the more predictable and abundant food supply that farming eventually provided appears to have supported substantially larger, more settled populations than foraging typically allowed.

This more nuanced picture of wheat domestication continues to inform modern crop science, since researchers today apply similar principles, deliberately identifying and selecting for advantageous genetic traits, to breed crop varieties with higher yields or greater resistance to disease and drought, essentially continuing, with far greater speed and precision, a process that began by accident in the fields of the Fertile Crescent thousands of years ago.