Brambilla Alice, Zehnder Noel, Bassano Bruno, Rossi Luca, Grossen Christine
Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland.
Alpine Wildlife Research Center, Gran Paradiso National Park Torino Italy.
Evol Appl. 2024 Jul 28;17(8):e13761. doi: 10.1111/eva.13761. eCollection 2024 Aug.
Improving the understanding of the causes and effects of anthropogenic hybridization is fundamental to ensure species conservation, particularly in the case of hybridization between wild species and their domestic relatives. Knowledge is missing for many species also because of a lack of appropriate tools for hybrid identification. Here, coupling genotype and phenotype analysis, we carried out an extensive investigation of ongoing hybridization in Alpine ibex , a mountain ungulate of conservation concern from a genetic perspective. By genotyping 63 diagnostic and 465 neutral SNPs, 20 suspected hybrids and 126 Alpine ibex without suspicious phenotype, representing 8 populations across a major part of the species distribution, we found evidence for ongoing hybridization between Alpine ibex and domestic goat. We identified different levels of hybridization including backcrosses into both Alpine ibex and domestic goat. Our results suggest a lack of reproductive barriers between the two species and good survival and reproductive success of the hybrids. Hybridization was locally intense, like a hybrid swarm, but not spread across the rest of the species distribution. Most of the hybrids were discovered in two locations in the north-west of Italy, while random sampling of individuals from different areas did not provide evidence of recent hybridization. Our method, based on amplicon sequencing of 63 diagnostic SNPs specifically developed for this purpose, allowed us to identify hybrids and backcrosses up to the fourth to fifth generations and was suitable for genetic samples of different quality, although with varying levels of certainty regarding the exact number of generations passed since hybridization. Based on the paired analysis of genotype and phenotype, we provide guidelines for the first identification of hybrids in the field and suggest a procedure for the reliable identification of hybrids.
提高对人为杂交的原因和影响的理解对于确保物种保护至关重要，特别是在野生物种与其家养亲属之间发生杂交的情况下。由于缺乏用于杂交鉴定的合适工具，许多物种的相关知识也很匮乏。在这里，我们结合基因型和表型分析，对阿尔卑斯野山羊（一种从遗传角度来看具有保护意义的山地有蹄类动物）正在进行的杂交进行了广泛调查。通过对63个诊断性单核苷酸多态性（SNP）和465个中性SNP进行基因分型，对20只疑似杂交个体和126只无可疑表型的阿尔卑斯野山羊进行分析，这些个体代表了该物种分布主要区域的8个种群，我们发现了阿尔卑斯野山羊与家养山羊之间正在进行杂交的证据。我们确定了不同程度的杂交，包括回交到阿尔卑斯野山羊和家养山羊。我们的结果表明这两个物种之间缺乏生殖隔离，并且杂交后代具有良好的生存和繁殖成功率。杂交在局部地区很强烈，就像一个杂交群体，但没有扩散到该物种分布的其他地区。大多数杂交个体是在意大利西北部的两个地点发现的，而从不同地区随机抽样的个体没有提供近期杂交的证据。我们基于专门为此目的开发的63个诊断性SNP的扩增子测序方法，能够识别出多达第四到第五代的杂交个体和回交个体，并且适用于不同质量的基因样本，尽管对于杂交后经过的确切代数的确定程度有所不同。基于基因型和表型的配对分析，我们提供了在野外首次识别杂交个体的指导方针，并提出了可靠识别杂交个体的程序。
