Department of Biological Sciences, Humboldt State University 1 Harpst Street, Arcata, California, 95521 ; Department of Biology, University of California Riverside, California, 92521.
Department of Biological Sciences, Humboldt State University 1 Harpst Street, Arcata, California, 95521.
Ecol Evol. 2014 Jun;4(12):2546-62. doi: 10.1002/ece3.1111. Epub 2014 May 24.
The North American deserts were impacted by both Neogene plate tectonics and Quaternary climatic fluctuations, yet it remains unclear how these events influenced speciation in this region. We tested published hypotheses regarding the timing and mode of speciation, population structure, and demographic history of the Mojave Fringe-toed Lizard (Uma scoparia), a sand dune specialist endemic to the Mojave Desert of California and Arizona. We sampled 109 individual lizards representing 22 insular dune localities, obtained DNA sequences for 14 nuclear loci, and found that U. scoparia has low genetic diversity relative to the U. notata species complex, comparable to that of chimpanzees and southern elephant seals. Analyses of genotypes using Bayesian clustering algorithms did not identify discrete populations within U. scoparia. Using isolation-with-migration (IM) models and a novel coalescent-based hypothesis testing approach, we estimated that U. scoparia diverged from U. notata in the Pleistocene epoch. The likelihood ratio test and the Akaike Information Criterion consistently rejected nested speciation models that included parameters for migration and population growth of U. scoparia. We reject the Neogene vicariance hypothesis for the speciation of U. scoparia and define this species as a single evolutionarily significant unit for conservation purposes.
北美的沙漠受到中新世板块构造和第四纪气候波动的影响，但这些事件如何影响该地区的物种形成仍不清楚。我们测试了有关莫哈韦边缘趾蜥蜴（Uma scoparia）的物种形成时间和模式、种群结构和历史动态的已发表假说，该蜥蜴是一种沙堤专家，分布于加利福尼亚州和亚利桑那州的莫哈韦沙漠。我们对代表 22 个孤岛沙丘的 109 只蜥蜴进行了采样，获得了 14 个核基因座的 DNA 序列，发现与 U. notata 物种复合体相比，U. scoparia 的遗传多样性较低，与黑猩猩和南部象海豹相当。使用贝叶斯聚类算法分析基因型并没有在 U. scoparia 中识别出离散的种群。使用隔离-迁徙（IM）模型和一种新的基于合并的假设检验方法，我们估计 U. scoparia 与 U. notata 在更新世时期分化。似然比检验和 Akaike 信息准则一致拒绝包括 U. scoparia 迁徙和种群增长参数的嵌套物种形成模型。我们拒绝中新世地理隔离假说，将 U. scoparia 定义为单一的具有进化意义的保护单位。
