Donkey Genomes Reveal Animal's Genomic History

The genomic landscape of the domestic donkey, Equus asinus, is reported in Science this week, providing molecular insights into an animal that has played a major role in human history as an essential beast of burden. Despite the donkey's continued importance in low- and middle-income countries, little is known about its history and the impact of human management on its genome. To investigate, a team led by scientists from CNRS constructed a comprehensive genome panel of 207 modern and 31 ancient donkeys, as well as 15 wild equids. The researchers uncovered a strong phylogeographic structure in modern donkeys that points to domestication starting from a unique African source around 5,000 BCE, followed by further expansions in this continent and Eurasia and ultimately returning to Africa. They also identified a previously unknown genetic lineage in the Levant around 200 BCE, which contributed increasing ancestry toward Asia, and determine that donkey management involved inbreeding and the production of giant bloodlines at a time when mules were essential to the Roman economy and military. "Efforts should continue to characterize the modern donkey diversity around the world, especially in Saudi Arabia, which is currently characterized by a single individual, as well as in Africa, for which no populations located south of the Equator have been sampled," the authors write. "Such efforts may not only refine the historical legacy of past populations into the modern world but also uncover the genetic basis of desert adaptations, which could prove invaluable for future donkey breeding in the face of global warming."