Data from: Phylogeography and ecological niche modelling of the desert iguana (Dipsosaurus dorsalis, Baird & Girard 1852) in the Baja California Peninsula

Understanding the factors that explain the patterns of genetic structure or phylogeographic breaks at an intraspecific level is key to inferring the mechanisms of population differentiation in its early stages. These topics have been well studied in the Baja California region, with vicariance and the dispersal ability of individuals being the prevailing hypothesis for phylogeographic breaks. In this study, we evaluated the phylogeographic patterns in the desert iguana (Dipsosaurus dorsalis), a species with a recent history in the region and spatial variation in life history traits. We analysed a total of 307 individuals collected throughout 19 localities across the Baja California Peninsula with 15 microsatellite DNA markers. Our data reveal the existence of three geographically discrete genetic populations with moderate gene flow and an isolation-by-distance pattern presumably produced by the occurrence of a refugium in the Cape region during the Pleistocene Last Glacial Maximum. Bayesian methods and ecological niche modelling were used to assess the relationship between population genetic structure and present and past climatic preferences of the desert iguana. We found that the present climatic heterogeneity of the Baja California Peninsula has a marked influence on the population genetic structure of the species, suggesting that there are alternative explanations besides vicariance. The information obtained in this study provides data allowing a better understanding of how historical population processes in the Baja California Peninsula can be understood from an ecological perspective.

解析种内水平上的遗传结构模式或系统地理分界（phylogeographic breaks）的影响因子，是推断种群早期分化机制的关键所在。下加利福尼亚半岛（Baja California Peninsula）区域内的相关研究主题已得到充分探讨，隔离分化（vicariance）与个体扩散能力是解释该区域系统地理分界的主流假说。本研究以沙漠鬣蜥（*Dipsosaurus dorsalis*）为研究对象，该物种在该区域的演化历史较短，且生活史特征存在空间变异。我们对采集自下加利福尼亚半岛19个采样点的共计307个个体进行了遗传分析，共使用15个微卫星DNA分子标记（microsatellite DNA markers）。研究数据显示，该物种存在3个地理上独立的遗传种群，种群间存在中等程度的基因流，且呈现距离隔离（isolation-by-distance）模式，该模式推测由更新世末次冰盛期（Pleistocene Last Glacial Maximum）期间开普地区存在的避难所（refugium）所引发。本研究采用贝叶斯方法与生态位模型（ecological niche modelling），评估了沙漠鬣蜥的种群遗传结构与其当前及历史气候偏好之间的关联。研究发现，下加利福尼亚半岛当前的气候异质性对该物种的种群遗传结构具有显著影响，这表明除隔离分化假说外，还存在其他可供选择的解释机制。本研究获取的相关数据，有助于从生态学视角更好地理解下加利福尼亚半岛的历史种群演化过程。