Humans have moved domestic animals around the globe for thousands of years. These have occasionally established feral populations in nature, often with devastating ecological consequences. To understand how natural selection shapes re-adaptation into the wild, we investigated one of the most successful colonizers in history, the European rabbit. By sequencing the genomes of 297 rabbits across three continents, we show that introduced populations exhibit a mixed wild–domestic ancestry. We show that alleles that increased in frequency during domestication were preferentially selected against in novel natural environments. Interestingly, causative mutations for common domestication traits sometimes segregate at considerable frequencies if associated with less drastic phenotypes (for example, coat colour dilution), whereas mutations that are probably strongly maladaptive in nature are absent. Whereas natural selection largely targeted different genomic regions in each introduced population, some of the strongest signals of parallelism overlap genes associated with neuronal or brain function. This limited parallelism is probably explained by extensive standing genetic variation resulting from domestication together with the complex mixed ancestry of introduced populations. Our findings shed light on the selective and molecular mechanisms that enable domestic animals to re-adapt to the wild and provide important insights for the mitigation and management of invasive populations.

数千年来，人类一直在全球范围内饲养家畜。它们偶尔会在自然界中建立野生种群，往往会带来毁灭性的生态后果。为了了解自然选择如何影响野外的重新适应，我们研究了历史上最成功的殖民者之一——欧洲兔子。通过对三大洲 297 只兔子的基因组进行测序，我们发现引入的兔子群体表现出野生与家养混合的血统。我们表明，在新的自然环境中，驯化过程中频率增加的等位基因会被优先选择。有趣的是，如果与不太剧烈的表型（例如毛色稀释）相关，常见驯化性状的致病突变有时会以相当大的频率分离，而本质上可能强烈适应不良的突变则不存在。尽管自然选择主要针对每个引入群体中的不同基因组区域，但一些最强的并行信号与与神经元或大脑功能相关的基因重叠。这种有限的平行性可能是由于驯化造成的广泛的遗传变异以及引入种群的复杂混合血统造成的。我们的研究结果揭示了使家畜重新适应野外的选择性和分子机制，并为缓解和管理入侵种群提供了重要见解。