Data from: Fine scale genetic structure among greater sage-grouse leks in central Nevada

Background: Mating systems that reduce dispersal and lead to non-random mating might increase the potential for genetic structure to arise at fine geographic scales. Greater sage-grouse (Centrocercus urophasianus) have a lek-based mating system and exhibit high site fidelity and skewed mating ratios. We quantified population structure by analyzing variation at 27,866 single-nucleotide polymorphisms in 140 males from ten leks (within five lek complexes) occurring in a small geographic region in central Nevada. Results: Lek complexes, and to a lesser extent individual leks, formed statistically identifiable clusters in ordination analyses, providing evidence for fine-scale geographic genetic differentiation. Lek geography predicted genetic differentiation even at a small geographic scale, which could be sharpened by strong site fidelity. Relatedness was also higher among individuals within lek complexes (and leks), suggesting that reproductive skew, where few males participate in most of the successful matings, could also potentially contribute to genetic differentiation. Models incorporating a habitat resistance surface as a proxy for potentially reduced movement due to landscape features indicated that both geographic distance and habitat suitability (i.e. preferred habitat) predicted genetic structure, with no significant effect of man-made barriers to movement (i.e. power lines and roads). Finally, we illustrate how data sets containing fewer loci (<4000) had less statistical precision and failed to detect the full degree of genetic structure. Conclusion: Our results suggest that habitat features and lek site geography of sage-grouse shape fine scale genetic structure, and highlight how larger data sets can have increased precision and accuracy for quantifying ecologically relevant genetic structure over small geographic scales.研究背景：能够降低扩散水平并引发非随机交配的交配体系，可能提升精细地理尺度下遗传结构形成的可能性。大艾草松鸡（Greater sage-grouse，学名Centrocercus urophasianus）采用求偶场（lek）交配体系，且表现出极高的领地保真度与偏态交配比率。我们通过分析内华达州中部小型地理区域内5个求偶场复合体（lek complex）内含的10个求偶场的140只雄性个体的27866个单核苷酸多态性（single-nucleotide polymorphism, SNP）位点变异，量化了种群遗传结构。 研究结果：在排序分析中，求偶场复合体以及次级的单个求偶场均形成了统计学上可辨识的聚类，为精细地理尺度下的遗传分化提供了直接证据。即便在极小的地理尺度下，求偶场的地理分布也能预测遗传分化，而高领地保真度可进一步强化这一效应。求偶场复合体（及单个求偶场）内个体的亲缘关系也显著更高，这表明少数雄性参与绝大多数成功交配的生殖倾斜现象，同样可能推动遗传分化进程。以生境阻力表面作为景观特征限制扩散的替代指标的模型显示，地理距离与生境适宜性（即偏好性生境）均可有效预测种群遗传结构，而人为造成的扩散障碍（即输电线路与道路）未产生显著影响。最后，我们证实了位点数量少于4000的数据集统计精度更低，且无法检测到完整的遗传分化程度。 研究结论：本研究结果表明，艾草松鸡的生境特征与求偶场地理分布共同塑造了精细尺度下的种群遗传结构；同时也凸显了更大规模的数据集可显著提升在小型地理尺度下量化生态学相关遗传结构的精度与准确性。