Geological and climatic changes in quaternary shaped the evolutionary history of Calibrachoa heterophylla, an endemic South-Atlantic species of petunia

Background: The glacial and interglacial cycles that characterized the Quaternary greatly affected the distribution and genetic diversity of plants. In the Neotropics, few phylogeographic studies have focused on coastal species outside of the Atlantic Rainforest. Climatic and sea level changes during the Quaternary played an important role in the evolutionary history of many organisms found in coastal regions. To contribute to a better understanding of plant evolution in this environment in Southern South America, we focused on Calibrachoa heterophylla (Solanaceae), an endemic and vulnerable wild petunia species from the South Atlantic Coastal Plain (SACP). Results: We assessed DNA sequences from two cpDNA intergenic spacers and analyzed them using a phylogeographic approach. The present phylogeographic study reveals the influence of complex geologic and climatic events on patterns of genetic diversification. The results indicate that C. heterophylla originated inland and subsequently ...背景：以冰期-间冰期旋回为典型特征的第四纪（Quaternary）深刻影响了植物的分布格局与遗传多样性水平。在新热带区（Neotropics），针对大西洋雨林以外的海岸物种开展的系统地理学（phylogeographic）研究仍较为匮乏。第四纪时期的气候波动与海平面变化，对海岸带诸多生物的演化历程具有关键塑造作用。为深化对南美南部该类海岸生境中植物演化过程的认知，本研究聚焦于源自南大西洋沿海平原（South Atlantic Coastal Plain, SACP）的特有且易危的野生矮牵牛物种——异色矮牵牛（Calibrachoa heterophylla，茄科Solanaceae）。 结果：本研究对两段叶绿体DNA（cpDNA）基因间隔区的DNA序列进行了分析，并采用系统地理学方法开展研究。本系统地理学研究揭示了复杂地质与气候事件对物种遗传分化格局的影响。结果表明，异色矮牵牛起源于内陆区域，随后……