The transition of human societies from hunter-gatherers to farmers and pastoralists is a more nuanced process than generally thought, according to a new study of peoples living in the highlands of southwest Ethiopia.
Much of the study of how people transitioned away from a lifestyle based mostly on food collected from the wild to one based on cultivated crops has focused on Europe, where the shift to agriculture, or «Neolithic transition,» concluded thousands of years ago. Based largely on genetic studies, the prevailing view is that the transition occurred mainly by population replacement rather than cultural change, said first author Shyamalika Gopalan, a graduate student at the time of the work advised by Brenna Henn, associate professor of anthropology at the University of California, Davis.
«The prevailing view has been that in Europe it was a wave of people that came through and replaced everyone,» Gopalan said.
The transition to agriculture is still underway in the highlands of southwest Ethiopia. Farmers and pastoralists started moving into the area 1,500 to 2,000 years ago, encroaching on the resident hunter-gatherers, and the groups have since been living alongside each other. That presents an opportunity to study this transition and the degree to which it represents replacement versus cultural change in the present day and a different global context.
The team, led by Henn and Barry Hewlett at Washington State University, Vancouver, collected DNA samples from five groups of people in the southwest highlands: the hunter-gatherer Chabu; the Majang, who practice small-scale cultivation of crops; and the Shekkacho, Bench and Sheko, who practice more intensive farming. The goals were to assess both the genetic ancestry of the different groups and demographic trends in the recent past.
«Based on genetics we can estimate the effective population size over the past 60 generations, or about 2,000 years,» Gopalan said.
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Materials provided by University of California — Davis. Original written by Andy Fell. Note: Content may be edited for style and length.