Data from: Genetic evidence for multiple events of hybridization between wolves and domestic dogs in the Iberian Peninsula

Hybridization between wild species and their domestic counterparts may represent a major threat to natural populations. However, high genetic similarity between the hybridizing taxa makes the detection of hybrids a difficult task and may hinder attempts to assess the impact of hybridization in conservation biology. In this work, we used a combination of 42 autosomal microsatellites together with Y-chromosome microsatellite-defined haplotypes and mtDNA sequences to investigate the occurrence and dynamics of wolf–dog hybridization in the Iberian Peninsula. To do this, we applied a variety of Bayesian analyses and a parallel set of simulation studies to evaluate (i) the differences between Iberian wolves and dogs, (ii) the frequency and geographical distribution of hybridization and (iii) the directionality of hybridization. First, we show that Iberian wolves and dogs form two well-differentiated genetic entities, suggesting that introgressive hybridization is not a widespread phenomenon shaping both gene pools. Second, we found evidence for the existence of hybridization that is apparently restricted to more peripheral and recently expanded wolf populations. Third, we describe compelling evidence suggesting that the dynamics of hybridization in wolf populations is mediated by crosses between male dogs and female wolves. More importantly, the observation of a population showing the occurrence of a continuum of hybrid classes forming mixed packs may indicate that we have underestimated hybridization. If future studies confirm this pattern, then an intriguing avenue of research is to investigate how introgression from free-ranging domestic dogs is enabling wolf populations to adapt to the highly humanized habitats of southern Europe while still maintaining their genetic differentiation.

野生物种与其家养同类之间的杂交，或对自然种群构成重大威胁。然而，杂交类群间极高的遗传相似性，使得杂种个体的检测难度陡增，也可能阻碍保护生物学领域中杂交影响评估工作的开展。本研究结合42个常染色体微卫星（autosomal microsatellites）、Y染色体微卫星定义的单倍型以及线粒体DNA（mtDNA）序列，对伊比利亚半岛内狼与犬的杂交发生情况及动态展开探究。为此，我们采用多种贝叶斯分析方法，并配套开展了一系列模拟研究，以评估三个核心目标：（1）伊比利亚狼与犬之间的遗传差异；（2）杂交事件的发生频率与地理分布；（3）杂交的方向性。首先，本研究证实伊比利亚狼与犬各自构成两个分化显著的遗传类群，表明渐渗杂交并非广泛塑造两类基因库的普遍现象。其次，研究发现杂交事件仅局限于边缘区域及近期扩张的狼种群中。第三，本研究提供了确凿证据，表明狼种群中的杂交动态由公犬与母狼的交配所介导。更为重要的是，某种群中存在连续梯度的杂交类群并形成混合狼群的观测结果，或表明我们此前低估了杂交事件的发生规模。若未来研究证实这一模式，那么一项颇具研究价值的方向便是探究：散养家犬的基因渐渗，如何在维持狼种群遗传分化的同时，帮助其适应南欧高度人工化的栖息环境。