Domestic donkeys (Equus asinus) have been highly important to humans for millennia, providing a reliable source of animal labor and long-distance transport in many cultures. However, regardless of the key role they played in ancient pastoral societies across Africa, Europe, and Asia, as well as the functions they still serve in low- and middle-income communities (especially in semi-arid and upland environments), relatively little is known about their origin, domestication timeline, and the impact of human management on their genomes.
Now, a research team led by the University Paul Sabatier in Toulouse, France, has performed a comprehensive genetic analysis of both modern and ancient donkeys, revealing their origins, expansion, and management practices. By evaluating 238 modern and ancient donkey genomes – 207 modern donkeys, 31 ancient donkeys, as well as 15 wild equids – the scientists found strong phylogeographic evidence supporting a single domestication event in eastern Africa over 7,000 years ago.
This event was followed by a series of expansions throughout Africa and into Eurasia, where several sub-populations ultimately became isolated and differentiated, most probably due to the aridification of Sahara. Eventually though, genetic variants from Europe and the Near East found their way back into western African donkey populations.
“We found a strong phylogeographic structure in modern donkeys that supports a single domestication in Africa ~5000 BCE, followed by further expansions in this continent and Eurasia and ultimately returning to Africa,” the study authors reported.
In addition, the analyses revealed a previously unknown genetic lineage in the Levant approximately 2,200 years ago that likely contributed to increased genetic flow toward Asian donkey populations. Finally, throughout history, donkey management involved the interbreeding and the production of large-sized bloodlines, particularly during a period when these creatures were essential to the Roman economy and military activities.
The study is published in the journal Science.
By Andrei Ionescu, Earth.com Staff Writer