Petunia altiplana Raw sequence reads

Phylogeographic history refers to the study of how species evolve and diversify in response to historical events, ecological factors, and demographic factors. The climate fluctuation of Pleistocene period marked a crucial time in shaping the distribution and genetic structure of many species, particularly those in Southern South America. In this chapter, we investigate the phylogeographic history of a highland grassland Petunia altiplana (Solanaceae) and its diversity and geographic distribution by using a population genomic approach with RAD-seq data. Our results indicates that during the glacial periods of Pleistocene, when the grasslands expanded, the lowland populations of P. altiplana reach the highlands amplifying its geographic distribution. We find that P. altiplana the genetic diversity of the population could be explained by their geographic division in North (NO), South (SO), and West (WE) population groups. The results show that isolation by distance was the main pattern of divergence, with elevation differences playing a key role in the division between WE and NO/SE populations. The NO and SE were divided by the Pelotas River and the expansion of the Araucaria Forest. Our findings indicate that the colonization of highlands by lowland populations, along with the impact of the Pelotas River and the expansion of the Araucaria Forest, played a significant role in the isolation of these populations.

系统地理学（phylogeography）是研究物种如何响应历史事件、生态因子及种群统计因子而发生演化与分化的学科。更新世（Pleistocene）的气候波动是塑造诸多物种分布格局与遗传结构的关键时期，尤以南美洲南部的物种为甚。本章节采用结合限制性酶切位点相关DNA测序（RAD-seq）的种群基因组学方法，对高原草原物种高原碧冬茄（*Petunia altiplana*，茄科Solanaceae）的系统地理学历史、遗传多样性与地理分布格局展开研究。研究结果显示，在更新世冰期阶段，草原群落扩张期间，高原碧冬茄的低地种群向高地迁移，进而扩大了该物种的地理分布范围。我们发现，高原碧冬茄的种群遗传多样性可通过其地理分区得到合理解释：可划分为北部（NO）、南部（SO）与西部（WE）三个种群类群。结果表明，距离隔离是种群分化的主要模式，而海拔差异在西部类群与北部/东南部类群的分化中发挥了关键作用。北部类群与东南部类群则被佩洛塔斯河（Pelotas River）与南洋杉林（Araucaria Forest）的扩张所分隔。本研究结果表明，低地种群向高地的拓殖，加之佩洛塔斯河与南洋杉林扩张的影响，是推动这些种群产生分化隔离的重要因素。