We analyzed whole-genome data from Italian wolves and dogs to assess the extent, timing, and functional relevance of dog introgression in the Italian wolf. Five wolves showed recent admixture within the last 3–7 generations, while historical introgressions under selection dated to the Bronze and Middle Ages involved genes linked to neuronal plasticity, vision, and immune response. These findings suggest that even limited dog ancestry may leave lasting genomic and phenotypic imprints on wild wolf populations.

Introgression resulting from anthropogenic hybridization may shape phenotypic traits in wild taxa, potentially altering species' ecology and human-wildlife interactions. This is particularly relevant in large carnivores such as gray wolves (Canis lupus) that are expanding into human-dominated landscapes. A notable example is the Italian wolf (C. l. italicus), which, after recovering from near extinction, now faces locally high levels of hybridization with the domestic dog (C. l. familiaris). Although wolf-dog hybridization is known to affect morphology, its effect on other phenotypic traits remains poorly investigated. We analyzed worldwide-distributed wolf and dog whole-genome data to assess the extent and timing of dog ancestry in a sample of 17 Italian wolves, and to explore dog introgression at behavior-related genes. Five Italian wolves, exhibiting varying levels of genome-wide dog ancestry (1-20%), were estimated to result from admixture events that occurred at least 3-7 generations before sampling (2005-2012). No overrepresentation of recent dog introgressions in behavior-related genes of admixed Italian wolves was detected. However, we identified signals of historical dog introgressions under putative selection, involving genes linked to neuronal plasticity, photoreceptor development, and immune responses. One of such introgressions likely occurred ~4,500 years ago during the Bronze Age and the other one ~1,000 years ago during the Middle Ages, suggesting that historical admixture might have shaped the Italian wolf evolutionary trajectories. Although preliminary and warranting further analyses, our results highlight the potential for phenotypic effects of wolf-dog hybridization to persist across generations, showing that even limited non-native ancestry can leave significant genomic footprints in wild populations.

人为杂交导致的基因渐渗（introgression）可塑造野生类群的表型性状，进而改变物种的生态特征以及人类与野生动物的相互作用。这一点在正扩张至人类主导景观中的大型食肉动物类群中尤为关键，比如灰狼（Canis lupus）。其中一个典型案例是意大利狼（C. l. italicus）：该物种从近乎灭绝的状态中恢复后，如今正面临与家犬（C. l. familiaris）局部高强度的杂交现象。尽管已知狼犬杂交会影响形态特征，但该过程对其他表型性状的影响仍鲜有研究。本研究分析了全球分布的狼与家犬的全基因组数据，以评估17只意大利狼样本中家犬血统的占比与传入时间，并探究家犬基因渐渗在行为相关基因中的分布情况。经评估，其中5只意大利狼的全基因组家犬血统占比介于1%-20%之间，其血统源自采样前（2005-2012年）至少3-7代的杂交事件。未在杂交意大利狼的行为相关基因中检测到近期家犬基因渐渗的富集现象。但本研究在推定受选择的基因组区域中，发现了历史家犬基因渐渗的信号，这些信号关联的基因涉及神经元可塑性、光感受器发育与免疫应答。其中一次渐渗事件大概率发生于约4500年前的青铜时代，另一次则发生于约1000年前的中世纪，这表明历史杂交事件可能塑造了意大利狼的演化轨迹。尽管本研究尚属初步且有待进一步验证，但研究结果凸显了狼犬杂交产生的表型效应可跨代留存，同时表明即便是少量的外来血统，也能在野生种群中留下显著的基因组印记。