Phylogenetic Systematics of Moraceae: Inflorescence Evolution and the Origin of a Pollination Mutualism

美国明尼苏达大学的乔治·韦伯伦博士利用桑树家族（桑科）现存成员的DNA序列，研究了桑树家族（桑科）的进化史。桑树是一种古老的开花植物。全世界有1000多种桑科植物，包括无花果、桑葚、菠萝蜜和面包果等经济上重要的水果。在桑科植物中，无花果（榕属的一种）因其与榕小蜂的复杂相互作用而成为生态学和进化研究的热点。以无花果种子为食的特殊黄蜂是700多种无花果的独家传粉者。无花果和黄蜂之间的互利关系激发了许多关于共同进化的研究，共同进化是两个物种相互响应而发生遗传变化的过程。对无花果授粉的生态学研究促进了我们对共同进化的理解，然而，导致无花果授粉的起源和进化阶段仍然几乎未知。本项目利用DNA测序和系统发育分析的新工具，探索桑树家族的早期历史，并确定无花果的近亲。在旧大陆热带地区的野外工作将集中于几种桑科植物的传粉生物学。以这种方式重建多样化模式，可以检验关于无花果独特授粉综合征起源的理论，并提高我们对植物进化总体趋势的理解。该项目将极大地扩展我们对生命之树一个重要分支的分类和系统发育知识。桑科经济上重要的成员包括观赏和食用无花果（Ficus），面包果和菠萝蜜（Artocarpus），纤维来源的桑树（Broussonetia）和主要的热带木材面包坚果（Brosimum）。桑树（Morus）作为蚕蛾的主要食物来源，在蚕丝的生产中也起着关键作用。了解这些植物的遗传关系对它们的可持续利用和保护非常重要。此外，该研究还为高级研究生提供了一个机会，将最先进的分子技术与以博物馆收藏为基础的生物多样性研究方法相结合。

Weiblen0128833Work by Dr. George Weiblen at the University of Minnesota examines the evolutionary history of the mulberry family (Moraceae) using the DNA sequences from the living members of this ancient lineage of flowering plants. There are more than 1000 species of Moraceae worldwide, including such economically important fruits as figs, mulberries, jackfruit and breadfruit. Among the Moraceae, the figs (species of the genus Ficus) have been a major focus of research in ecology and evolution because of their complex interactions with fig wasps. Specialized wasps that feed on fig seeds are the exclusive pollinators of over 700 species of figs. The mutually beneficial relationship between figs and their wasps has stimulated much research on coevolution, the process by which two species undergo genetic change in response to each other. Ecological studies of fig pollination have advanced our understanding of coevolution, and yet the origins and evolutionary stages leading to fig pollination have remained virtually unknown. This project uses new tools of DNA sequencing and phylogenetic analysis to probe the early history of the mulberry family and to identify the closest relatives of the figs. Field work in the Old World tropics will focus on pollination biology of several Moraceae. Reconstructing patterns of diversification in this way makes it possible to test theories on the origin of the unique fig pollination syndrome, and to improve our understanding of general trends in floral evolution.The project will significantly expand our taxonomic and phylogenetic knowledge of an important branch of the tree of life. Economically significant members of the Moraceae include ornamental and edible figs (Ficus), breadfruit and jackfruit (Artocarpus), paperbark mulberry (Broussonetia), a source of fiber, and breadnut (Brosimum), a major tropical timber. Mulberry (Morus) also plays a key role in the production of silk as the main food source for silk moths. Understanding how these plants are related genetically is important for their sustainable use and conservation. In addition, the research provides an opportunity for advanced graduate training in state-of-the-art molecular techniques combined with museum collections-based approaches to the study of biodiversity.