Data from: Spatial heterogeneity in genetic relatedness among house sparrows along an urban-rural gradient as revealed by individual-based analysis

Understanding factors that shape patterns of kinship in sedentary species is important for evolutionary ecologists as well as conservation biologists. Yet, how patterns of relatedness are hierarchically structured in space remains poorly known, even in common species. Here we use information from 16 polymorphic microsatellite DNA markers to study how small-scale kinship structure varies among house sparrows (Passer domesticus) along an urban-rural gradient. Average levels of relatedness were higher among urban individuals than among individuals from rural areas, suggesting lower rates of dispersal in more built up habitats. Comparison of observed levels of relatedness with simulated distributions of known kinship values showed that central urban individuals had the highest proportion of closely-related conspecifics in their immediate neighbourhood. Spatial auto-correlograms supported this small-scale genetic structure and further indicated stronger effects of genetic drift and/or limited dispersal in urban populations. Results of this study underscore the importance of individual-level analyses as a complementary approach to traditional population-level analyses when studying genetic population structure over small spatial scales.

探究塑造定居性物种亲缘关系模式的影响因素，对于进化生态学家与保护生物学家而言均具有重要意义。然而，即便在常见物种中，亲缘相关度如何在空间上呈现层级结构，目前仍未得到充分解析。本研究借助16个多态性微卫星DNA标记（polymorphic microsatellite DNA markers），分析家麻雀（Passer domesticus）的小型亲缘结构沿城乡梯度的变化规律。结果显示，城市个体间的平均亲缘相关度高于乡村个体，这表明人类活动密集生境中的个体扩散率更低。将观测得到的亲缘相关度与已知亲缘值的模拟分布进行对比后发现，城市核心区域个体的邻近生境中，近缘同种个体的占比最高。空间自相关图（spatial auto-correlograms）验证了这一小型空间遗传结构，并进一步揭示城市种群中遗传漂变（genetic drift）和/或扩散受限的效应更强。本研究结果强调，在探究小型空间尺度下的遗传种群结构时，以个体水平分析作为传统种群水平分析的补充方法具有重要价值。