Data from: The biogeography of kin discrimination across microbial neighborhoods

The spatial distribution of potential interactants is critical to social evolution in all cooperative organisms. Yet the biogeography of microbial kin discrimination at the scales most relevant to social interactions is poorly understood. Here we resolve the microbiogeography of social identity and genetic relatedness in local populations of the model cooperative bacterium <i>Myxococcus xanthus</i> at small spatial scales across which the potential for dispersal is high. Using two criteria of relatedness – colony-merger compatibility during cooperative motility and DNA-sequence similarity at highly polymorphic loci - we find that relatedness decreases greatly with spatial distance even across the smallest scale transition. Both social and genetic relatedness are maximal within individual fruiting bodies at the micrometer scale but are much lower already across adjacent fruiting bodies at the millimeter scale. Genetic relatedness was found to be yet lower among centimeter-scale samples, whereas social-allotype relatedness decreased further only at the meter scale, at and beyond which the probability of social or genetic identity among randomly sampled isolates is effectively zero. Thus, in <i>M. xanthus</i>, high-relatedness patches form a rich mosaic of diverse social allotypes across fruiting-body neighborhoods at the millimeter scale and beyond. Individuals that migrate even short distances across adjacent groups will frequently encounter allotypic conspecifics and territorial kin discrimination may profoundly influence the spatial dynamics of local migration. Finally, we also found that the phylogenetic scope of intra-specific biogeographic analysis can affect the detection of spatial structure, as some patterns evident in clade-specific analysis were masked by simultaneous analysis of all strains.潜在交互伙伴的空间分布，对于所有合作生物的社会演化而言至关重要。然而，与社会交互最相关尺度下的微生物亲缘识别（microbial kin discrimination）生物地理学，目前仍鲜为人知。本研究在扩散潜力较高的小空间尺度下，解析了模式合作细菌黄色粘球菌（Myxococcus xanthus）局域种群的社会身份与遗传亲缘度的微生物地理学格局。本研究采用两类亲缘度判定标准——合作运动过程中的菌落融合兼容性，以及高度多态性位点的DNA序列相似性——发现即便在最小的空间尺度间隔下，亲缘度也会随空间距离显著下降。社会亲缘度与遗传亲缘度均在微米尺度的单个子实体内部达到峰值，但在毫米尺度的相邻子实体之间便已大幅降低。厘米尺度样本间的遗传亲缘度进一步降低，而社会异型亲缘度仅在米级尺度及以上才会进一步下降；在此尺度及更大尺度下，随机分离株间具备社会或遗传同一性的概率几乎为零。由此可见，在黄色粘球菌中，高亲缘度斑块在毫米尺度及更大尺度的子实体邻域内，形成了由多样社会异型型构成的丰富镶嵌格局。即便仅在相邻群体间迁移短距离的个体，也会频繁遭遇异型同种个体，而领地性亲缘识别或会深刻影响局域迁移的空间动态。此外，本研究还发现，种内生物地理学分析的系统发育范围会影响空间结构的检测效果：仅针对进化枝的分析中显现的部分模式，在对所有菌株同时进行分析时会被掩盖。