Data from: Ancient and modern DNA reveal dynamics of domestication and cross-continental dispersal of the dromedary

Dromedaries have been fundamental to the development of human societies in arid landscapes and for long-distance trade across hostile hot terrains for 3,000 y. Today they continue to be an important livestock resource in marginal agro-ecological zones. However, the history of dromedary domestication and the influence of ancient trading networks on their genetic structure have remained elusive. We combined ancient DNA sequences of wild and early-domesticated dromedary samples from arid regions with nuclear microsatellite and mitochondrial genotype information from 1,083 extant animals collected across the species’ range. We observe little phylogeographic signal in the modern population, indicative of extensive gene flow and virtually affecting all regions except East Africa, where dromedary populations have remained relatively isolated. In agreement with archaeological findings, we identify wild dromedaries from the southeast Arabian Peninsula among the founders of the domestic dromedary gene pool. Approximate Bayesian computations further support the “restocking from the wild” hypothesis, with an initial domestication followed by introgression from individuals from wild, now-extinct populations. Compared with other livestock, which show a long history of gene flow with their wild ancestors, we find a high initial diversity relative to the native distribution of the wild ancestor on the Arabian Peninsula and to the brief coexistence of early-domesticated and wild individuals. This study also demonstrates the potential to retrieve ancient DNA sequences from osseous remains excavated in hot and dry desert environments.三千年来，单峰驼（Dromedary）一直是干旱地区人类社会发展的核心基石，亦是跨炎热恶劣地形开展长途贸易的关键依托。时至今日，其仍是边缘农业生态区重要的畜牧资源。然而，单峰驼的驯化历史，以及古代贸易网络对其遗传结构的影响，长期以来始终未被厘清。本研究整合了来自干旱区域的野生与早期驯化单峰驼样本的古DNA序列，以及覆盖该物种全分布范围的1083份现存个体的核微卫星（nuclear microsatellite）与线粒体基因型（mitochondrial genotype）数据。研究观察到现代单峰驼种群几乎无系统地理学（phylogeographic）信号，这表明其存在广泛的基因交流，且该现象几乎波及所有区域，唯有东非例外——当地单峰驼种群始终保持相对独立的演化状态。结合考古学研究结果，本研究确认阿拉伯半岛东南部的野生单峰驼属于驯化单峰驼基因库的创始种群之一。近似贝叶斯计算（Approximate Bayesian computations）进一步验证了“野生种群复育（restocking from the wild）”假说：单峰驼先经历初始驯化，随后与现已灭绝的野生个体发生基因渐渗（introgression）。相较于其他与野生祖先存在长期基因交流的家畜，单峰驼的初始遗传多样性相对较高——这一现象与其野生祖先仅在阿拉伯半岛有原生分布，以及早期驯化个体与野生个体的共存时间较短相契合。本研究同时证明，从炎热干旱沙漠环境中出土的骨遗骸中获取古DNA序列具备可行性。