Data from: The biogeography of kin discrimination across microbial neighbourhoods

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 Myxococcus xanthus 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 relatedness and genetic relatedness are maximal within individual fruiting bodies at the micrometre scale but are much lower already across adjacent fruiting bodies at the millimetre scale. Genetic relatedness was found to be yet lower among centimetre-scale samples, whereas social allotype relatedness decreased further only at the metre scale, at and beyond which the probability of social or genetic identity among randomly sampled isolates is effectively zero. Thus, in M. xanthus, high-relatedness patches form a rich mosaic of diverse social allotypes across fruiting body neighbourhoods at the millimetre 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 intraspecific 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.潜在互作个体的空间分布对所有合作生物的社会演化至关重要。然而，在与社会互动最相关的尺度上，微生物亲缘识别（kin discrimination）的生物地理格局仍知之甚少。本研究针对模式合作细菌黄色黏球菌（Myxococcus xanthus）的局域种群，在扩散潜力较高的小空间尺度上，解析了社会身份与遗传亲缘关系的微生物生物地理格局。本研究采用两类亲缘关系判定标准——合作运动过程中的菌落融合兼容性（colony-merger compatibility）以及高多态性位点（highly polymorphic loci）的DNA序列相似性——发现即便在最小的尺度跨度内，亲缘关系也会随空间距离增加而显著降低。在微米尺度的单个子实体（fruiting body）内部，社会亲缘关系与遗传亲缘关系均达到最高水平，但在毫米尺度的相邻子实体之间，二者均已大幅降低。厘米尺度的样本间遗传亲缘关系进一步降低，而社会识别异型（social allotype）亲缘关系仅在米尺度及以上才会进一步下降；在该尺度及更大尺度下，随机分离得到的菌株间具有社会或遗传身份一致性的概率几乎为零。因此，在黄色黏球菌中，高亲缘性斑块在毫米尺度及更大尺度的子实体邻域内，形成了由多样社会识别异型构成的丰富镶嵌格局。即便在相邻类群间短距离迁移的个体，也会频繁遭遇异型同种个体；领地性亲缘识别可能会对局域迁移的空间动态产生深远影响。最后，本研究还发现，种内生物地理分析的系统发育范围会影响空间结构的检测效果——仅在支系特异性分析中显现的部分格局，会因同时分析所有菌株而被掩盖。