Data from: Genetic diversity is largely unpredictable but scales with museum occurrences in a species-rich clade of Australian lizards

Genetic diversity is a fundamental characteristic of species and is affected by many factors, including mutation rate, population size, life history and demography. To better understand the processes that influence levels of genetic diversity across taxa, we collected genome-wide restriction-associated DNA data from more than 500 individuals spanning 76 nominal species of Australian scincid lizards in the genus Ctenotus. To avoid potential biases associated with variation in taxonomic practice across the group, we used coalescent-based species delimitation to delineate 83 species-level lineages within the genus for downstream analyses. We then used these genetic data to infer levels of within-population genetic diversity. Using a phylogenetically informed approach, we tested whether variation in genetic diversity could be explained by population size, environmental heterogeneity or historical demography. We find that the strongest predictor of genetic diversity is a novel proxy for census population size: the number of vouchered occurrences in museum databases. However, museum occurrences only explain a limited proportion of the variance in genetic diversity, suggesting that genetic diversity might be difficult to predict at shallower phylogenetic scales.遗传多样性是物种的基本特征，其受突变率、种群规模、生活史与种群统计学等诸多因素影响。为更深入地解析驱动不同类群遗传多样性水平差异的演化过程，本研究采集了覆盖澳大利亚石龙子科锦蛇蜥属（Ctenotus）76个名义物种的500余号个体的全基因组限制性关联DNA（restriction-associated DNA）数据。为规避该类群分类实践差异引发的潜在偏倚，我们采用基于溯祖理论的物种界定方法，对该属内的类群进行划分，最终得到83个物种水平的演化支系用于后续分析。随后，我们依托这些遗传数据推断种群内部的遗传多样性水平。我们采用系统发育校正的分析框架，检验遗传多样性的变异是否可由种群规模、环境异质性或历史种群动态予以解释。本研究发现，对遗传多样性预测能力最强的指标是一项针对普查种群规模的全新替代变量：博物馆数据库中经凭证标本确认的物种出现记录数量。然而，博物馆记录仅能解释遗传多样性变异的有限比例，这表明在较浅的系统发育尺度下，遗传多样性或难以实现精准预测。