The use of genomic and phenotypic data to scan for outliers is a mainstay for studies of hybridization and speciation. Geographic cline analysis of natural hybrid zones is widely used to identify putative signatures of selection by detecting deviations from baseline patterns of introgression. As with other outlier-based approaches, demographic histories can make neutral regions appear to be under selection and vice versa. In this study, we use a forward-time individual-based simulation approach to evaluate the robustness of geographic cline analysis under different evolutionary scenarios. We modelled multiple stepping-stone hybrid zones with distinct age, deme sizes, and migration rates, and evolving under different types of selection. We found that drift distorts cline shapes and increases false positive rates for signatures of selection. This effect increases with hybrid zone age, particularly if migration between demes is low. Drift can also distort the signature of deleterious effects of hybridization, with genetic incompatibilities and particularly underdominance prone to spurious typing as adaptive introgression. Our results suggest that geographic clines are most useful for outlier analysis in young hybrid zones with large populations of hybrid individuals. Current approaches may overestimate adaptive introgression and underestimate selection against maladaptive genotypes.

中文翻译：

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使用基因组数据进行地理克隆分析的狭窄窗口：年龄、漂移和迁移对错误率的影响

使用基因组和表型数据扫描异常值是杂交和物种形成研究的支柱。自然杂交区的地理克隆分析被广泛用于通过检测渐渗基线模式的偏差来识别推定的选择特征。与其他基于离群值的方法一样，人口统计历史可以使中性区域看起来正在被选择，反之亦然。在这项研究中，我们使用基于前向时间个体的模拟方法来评估不同进化情景下地理克隆分析的稳健性。我们模拟了多个具有不同年龄、族群大小和迁移率的垫脚石混合区，并在不同类型的选择下进化。我们发现漂移会扭曲克隆形状并增加选择签名的误报率。这种影响随着混合区年龄的增加而增加，特别是如果族群之间的迁移很低。漂移还可以扭曲杂交有害影响的特征，遗传不相容性，特别是弱优势，容易产生虚假分型作为适应性基因渗入。我们的结果表明，地理克隆对于具有大量杂交个体的年轻杂交区的异常值分析最有用。目前的方法可能高估了适应性基因渗入并低估了针对适应不良基因型的选择。我们的结果表明，地理克隆对于具有大量杂交个体的年轻杂交区的异常值分析最有用。目前的方法可能高估了适应性基因渗入并低估了针对适应不良基因型的选择。我们的结果表明，地理克隆对于具有大量杂交个体的年轻杂交区的异常值分析最有用。目前的方法可能高估了适应性基因渗入并低估了针对适应不良基因型的选择。