Department of Genetics, University of Georgia, Athens, GA 30602, USA.
Mol Ecol. 2012 Oct;21(20):4970-82. doi: 10.1111/j.1365-294X.2012.05755.x. Epub 2012 Sep 18.
Landscape genetic studies use spatially explicit population genetic information to determine the physical and environmental causes of population genetic structure on regional scales. Comparative studies that identify common barriers to gene flow across multiple species within a community are important to both understand the evolutionary trajectories of populations and prioritize habitat conservation. Here, we use a comparative landscape genetic approach to ask whether gradients in temperature or precipitation seasonality structure genetic variation across three codistributed tree species in Central America, or whether a simpler (geographic distance) or more complex, species-specific environmental niche model is necessary to individually explain population genetic structure. Using descriptive statistics and causal modelling, we find that different factors best explain genetic distance in each of the three species: environmental niche distance in Bursera simaruba, geographic distance in Ficus insipida and historical barriers to gene flow or cryptic reproductive barriers for Brosimum alicastrum. This study confirms suggestions from previous studies of Central American tree species that imply that population genetic structure of trees in this region is determined by complex interactions of both historical and current barriers to gene flow.
景观遗传学研究利用空间明确的种群遗传信息来确定区域尺度上种群遗传结构的物理和环境原因。在一个群落中识别多个物种之间共同的基因流动障碍的比较研究，对于理解种群的进化轨迹和优先保护栖息地都很重要。在这里，我们使用比较景观遗传学的方法来探讨温度或降水季节性梯度是否构成中美洲三种共分布树种遗传变异的结构，或者是否需要更简单（地理距离）或更复杂、特定于物种的环境生态位模型来单独解释种群遗传结构。通过描述性统计和因果建模，我们发现不同的因素可以最好地解释这三个物种中的每一个的遗传距离：Bursera simaruba 中环境生态位距离，Ficus insipida 中的地理距离，以及 Brosimum alicastrum 的历史基因流障碍或隐生生殖障碍。本研究证实了先前对中美洲树种的研究的建议，即该地区树木的种群遗传结构是由历史和当前基因流障碍的复杂相互作用决定的。
