Phylogenetic Systematics of Nolana (Solanaceae) and Biogeographic Implications for the Atacama and Peruvian Deserts

狄龙南美洲的秘鲁和阿塔卡马沿海沙漠(S纬度8-28度)是地球上最干燥、最不适宜居住的地貌，通常可以与火星上的地貌相提并论。虽然这些沙漠基本上没有植物，但当地季节性积累的雾降水使植被成为可能。生物学家对海洋岛屿的物种形成进行了研究，但较少研究的是存在于大陆生态系统中、被中间生境隔绝的“虚拟”岛屿。在沿海沙漠中，这样的群落被称为“洛马斯群系”，以不同距离的极度干旱栖息地隔开的植被岛的形式出现。洛马斯群岛代表着一个虚拟的群岛，在很大程度上没有人研究过。它们为检验进化模式和检验生物地理假说提供了完美的实验室。诺拉纳属(茄科或土豆科)植物有85种，是阿塔卡马和秘鲁沙漠植物区系中最常见的成员之一，每个洛马斯岛上至少有一个物种。Nolana物种在生长习性、营养和花卉形态以及生态偏好方面表现出广泛的差异，使它们成为研究进化模式、分类关系和分布模式的理想对象。菲尔德自然历史博物馆的Michael Dillon博士和他的同事Jun wen博士将在智利和秘鲁沿海地区进行全面的实地研究，以收集至少75种Nolana。三个核基因(GBSSI、硝酸还原酶(NIA)内含子、核糖体5S)和两个叶绿体基因(TRNC-trnD区，ndhF)将从所有这些样本中进行DNA测序，以测量突变差异并研究Nolana的进化和生物地理史。分子和形态结果将被用来检验沿海沙漠大范围分布模式的假说。此外，诺拉纳的演化史提供了沿海沙漠的年龄和起源及其对短期事件(ENSO或厄尔尼诺现象)和长期事件(冰川周期和海平面变化)的反应的线索。这项研究的其他成果将包括一本全面的诺拉纳分类专著和广泛开发的网站可访问信息。长期以来，岛屿及其生物群一直对进化论和生物地理学感兴趣。该项目的结果将对诺拉纳的遗传多样性提供重要的见解，并将制定在沿海沙漠环境中保护受威胁和濒危物种的战略。该项目将为一名研究生和一名博士后研究员提供植物系统学和生物地理学领域和实验室方法学方面的培训。这项研究将与智利和秘鲁的科学家和学生密切合作开展。我们的发现不仅会引起植物学家和生态学家的兴趣，也会引起气候学家、生态生理学家和地质考古学家的兴趣。

0415573Dillon The Peruvian and Atacama coastal deserts of South America (8-28 degrees S latitude) are the planet's driest and most inhospitable landscapes, often compared to those found on Mars. Although these deserts are largely devoid of plants, there are "oases" of vegetation made possible by local seasonal accumulation of fog precipitation. Biologists have studied speciation in oceanic islands, but, less studied are "virtual" islands that exist within continental ecosystems and are isolated by intervening habitats. In the coastal deserts, such communities are called "lomas formations" and occur as discrete islands of vegetation, separated by varying distances of hyper-arid habitat. The lomas formations represent a virtual archipelago, largely unstudied. They offer the perfect laboratory for examining evolutionary patterns and testing biogeographic hypotheses. With 85 species, the plant genus Nolana (Solanaceae or Potato Family) is one of the most frequently encountered members of the Atacama and Peruvian desert flora, with at least one species occurring on every lomas island. Nolana species exhibit extensive variation in growth habit, vegetative and floral morphology, and ecological preferences, making them an ideal subject for investigating evolutionary models, taxonomic relationships, and distribution patterns. Dr. Michael Dillon and his colleague Dr. Jun Wen at the Field Museum of Natural History will conduct comprehensive field studies in coastal Chile and Peru to collect at least 75 species of Nolana. Three nuclear genes (GBSSI, nitrate reductase (NIA) introns, ribosomal 5S) and two chloroplast genes (trnC-trnD region, ndhF ) will be DNA-sequenced from all these samples to measure mutational differences and to examine the evolution and biogeographic history of Nolana. Molecular and morphological results will be used to test hypotheses of broad-scale distribution patterns in the coastal deserts. Further, the evolutionary history of Nolana holds clues to the age and origin of the coastal deserts and their reactions to short-term events (ENSO or El Nino phenomena) and longer-term events (glacial cycles and sea-level changes). Additional products from the research will include a comprehensive taxonomic monograph of Nolana and extensive development of website accessible information.Islands and their biotas have long interested students of evolution and biogeography. The results of this project will provide important insights into the genetic diversity of Nolana and will establish strategies for the conservation of threatened and endangered species within coastal desert environments. The project will provide training for a graduate student and a post-doctoral researcher in both field and laboratory methodologies in plant systematics and biogeography. The research will be developed in close collaboration with scientists and students in Chile and Peru. Our discoveries will be of interest not only to plant scientists and ecologists, but also to climatologists, ecophysiologists and geoarcheologists.