Domestication begins with the selection of animals showing less fear of humans. In most domesticates, selection signals for tameness have been superimposed by intensive breeding for economical or other desirable traits. Old World camels, conversely, have maintained high genetic variation and lack secondary bottlenecks associated with breed development. By re-sequencing multiple genomes from dromedaries, Bactrian camels, and their endangered wild relatives, here we show that positive selection for candidate genes underlying traits collectively referred to as ‘domestication syndrome’ is consistent with neural crest deficiencies and altered thyroid hormone-based signaling. Comparing our results with other domestic species, we postulate that the core set of domestication genes is considerably smaller than the pan-domestication set – and overlapping genes are likely a result of chance and redundancy. These results, along with the extensive genomic resources provided, are an important contribution to understanding the evolutionary history of camels and the genomic features of their domestication.

驯化开始于选择对人类不那么害怕的动物。在大多数驯化动物中，驯服的选择信号已被经济或其他理想性状的集约化育种叠加。相反，旧世界的骆驼保持着较高的遗传变异，并且缺乏与品种发展相关的次要瓶颈。通过对单峰驼、双峰驼和它们濒临灭绝的野生近缘种的多个基因组进行重新测序，我们在这里表明，对统称为“驯化综合征”的潜在特征的候选基因的阳性选择与神经嵴缺陷和基于甲状腺激素的信号传导改变一致. 将我们的结果与其他国内物种进行比较，我们假设驯化基因的核心集比泛驯化集要小得多——重叠基因可能是偶然和冗余的结果。这些结果连同所提供的广泛基因组资源，对理解骆驼的进化历史及其驯化的基因组特征做出了重要贡献。