"Diversity is unevenly distributed within species"
Global efforts to conserve species have been strongly influenced by the heterogeneous distribution of species diversity across the Earth. This is manifest in conservation efforts focused on diversity hotspots. The conservation of genetic diversity _within_ an individual species is also an important factor in its survival in the face of environmental changes and disease. Here we show that diversity within species is also distributed unevenly. Using simple genealogical models, we show that genetic distinctiveness has a power-law distribution. This property implies that a disproportionate fraction of the diversity is concentrated in small sub-populations. Small groups are of such importance to overall population diversity that even without extrinsic perturbations, there are large fluctuations in diversity due to extinctions of these small groups. We also show that diversity can be geographically non-uniform, potentially including sharp boundaries between distantly related organisms, without extrinsic causes such as barriers to gene flow or past migration events. Our theoretical results agree with experimental results on the distribution of diversity in global samples of Pseudomonas bacteria. The results suggest that conservation efforts that target specific highly unique groups and ensuring their continued reproduction can save much of the diversity, even after a large population loss.