Recent empirical studies have demonstrated that speciation with gene flow is more common than previously thought. From a conservation perspective, the potential negative effects of hybridization raise concerns on the genetic integrity of endangered species. However, introgressive hybridization has also been growingly recognized as a source of diversity and new advantageous alleles. Carbonell's wall lizard (Podarcis carbonelli) is an endangered species whose distribution overlaps with four other congeneric species. Our goal here was to determine whether P. carbonelli is completely reproductively isolated from its congeners and to evaluate the relevance of hybridization and interspecific gene flow for developing a conservation plan. We used restriction site associated DNA (RAD) sequencing to discover SNPs in samples from four contact zones between P. carbonelli and four other species. Principal component analysis, multilocus genotype assignment and interspecific heterozygosity suggest incomplete reproductive isolation and ongoing gene flow between species. However, hybridization dynamics vary across all pairs, suggesting complex interactions between multiple intrinsic and extrinsic barriers. Despite seemingly ubiquitous interspecific gene flow, we found evidence of strong reproductive isolation across most contact zones. Instead, indirect effects of hybridization like waste of reproductive effort in small isolated populations may be more problematic. Our results highlight the need to further evaluate the consequences of introgression for P. carbonelli, both on a geographic and genomic level and included in a comprehensive and urgently needed conservation plan. Besides, those findings will add important insights on the potential effects of hybridization and introgression for endangered species.

中文翻译：

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濒临灭绝的Podarcis Carbonelli和高度分化的同属物种之间不同程度的基因渗入


最近的实证研究表明，基因流形成的物种比以前想象的更为常见。从保护的角度来看，杂交的潜在负面影响引起了人们对濒危物种遗传完整性的担忧。然而，渐渗杂交也越来越被认为是多样性和新的有利等位基因的来源。卡博内尔壁蜥蜴 (Podarcis Carbonelli) 是一种濒临灭绝的物种，其分布与其他四种同属物种重叠。我们的目标是确定 P. Carbonelli 是否与其同系物完全生殖隔离，并评估杂交和种间基因流对于制定保护计划的相关性。我们使用限制性位点相关 DNA (RAD) 测序来发现来自 P. Carbonelli 和其他四种物种之间的四个接触区的样品中的 SNP。主成分分析、多位点基因型分配和种间杂合性表明不完全的生殖隔离和物种之间持续的基因流动。然而，所有对之间的杂交动力学各不相同，表明多个内在和外在障碍之间存在复杂的相互作用。尽管种间基因流看似无处不在，但我们发现大多数接触区都存在强烈的生殖隔离的证据。相反，杂交的间接影响，比如在孤立的小群体中浪费繁殖努力，可能会产生更大的问题。我们的结果强调需要在地理和基因组水平上进一步评估 P. Carbonelli 基因渗入的后果，并将其纳入全面且迫切需要的保护计划中。 此外，这些发现将为濒危物种杂交和基因渗入的潜在影响提供重要见解。