Species often experience spatial environmental heterogeneity across their range, and populations may exhibit signatures of adaptation to local environmental characteristics. Other population genetic processes, such as migration and genetic drift, can impede the effects of local adaptation. Genetic drift in particular can have a pronounced effect on population genetic structure during large-scale geographic expansions, where a series of founder effects leads to decreases in genetic variation in the direction of the expansion. Here, we explore the genetic diversity of a desert lizard that occupies a wide range of environmental conditions and that has experienced post-glacial expansion northwards along two colonization routes. Based on our analyses of a large SNP data set, we find evidence that both climate and demographic history have shaped the genetic structure of populations. Pronounced genetic differentiation was evident between populations occupying cold versus hot deserts, and we detected numerous loci with significant associations with climate. The genetic signal of founder effects, however, is still present in the genomes of the recently expanded populations, which comprise subsets of genetic variation found in the southern populations.

中文翻译：

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气候和人口历史对沙漠角蜥（Phrynosoma platyrhinos）种群基因组变异的影响

物种通常在其范围内经历空间环境异质性，并且种群可能表现出适应当地环境特征的特征。其他种群遗传过程，例如迁移和遗传漂变，可能会阻碍局部适应的影响。在大规模地理扩张期间，遗传漂变尤其会对种群遗传结构产生显着影响，其中一系列创始人效应导致沿扩张方向的遗传变异减少。在这里，我们探索了沙漠蜥蜴的遗传多样性，这种蜥蜴占据了广泛的环境条件，并且经历了冰川后沿两条殖民路线向北扩张。基于我们对大型 SNP 数据集的分析，我们发现证据表明气候和人口历史都塑造了人口的遗传结构。占据寒冷沙漠和炎热沙漠的种群之间明显存在明显的遗传差异，我们发现了许多与气候有显着关联的位点。然而，创始人效应的遗传信号仍然存在于最近扩大的种群的基因组中，这些种群包括在南方种群中发现的遗传变异子集。