Experimental studies on the origins of diversity

这个研究项目解决了生物学中的一个核心问题：多样性的起源。现有理论的大部分都是关于它的维持条件，因为它已经存在了。我的目标是首先找出产生多样性的因素。我用微生物系统在两种情况下研究多样性的起源。第一个是适应性辐射——一个谱系迅速多样化，成为一系列生态和表型上不同的生态位专家——加拉帕戈斯雀和非洲裂谷湖鲷就是典型的例子。我们利用土壤中的荧光假单胞菌在实验室中研究了自适应辐射。我们的目标是了解控制多样化速度和程度的机制。第二个是构成多样化的过程，即适应。直到最近，我们对适应的理解还没有超越达尔文最初的观点，即自然选择是负责任的机制。我们的工作旨在测试在过去十年中发展起来的日益复杂的适应理论中最令人信服的预测。我们使用丝状真菌细粒曲霉进行这项工作，因为它具有许多独特的特征，使我们能够在实验室中记录适应性进化，并梳理出潜在的遗传变化。我的实验室为实验进化和相关领域（实验设计、微生物学）的培训提供了绝佳的机会，我与合作者保持着密切的联系，他们为定量遗传学、统计学、建模和微生物遗传学的培训提供了互补的专业知识。这项工作使生物学中一些最古老、最基本的问题第一次进入了实验研究。我希望这些结果能引起广泛的兴趣，有助于了解进化的基础知识，以及医学和保护生物学中的更多应用问题。

This research program addresses one of the central problems in biology: the origin of diversity. The bulk of existing theory concerns the conditions for its maintenance, given that it already exists. My goal is to identify the factors responsible for generating diversity in the first place. I use microbial systems to study the origins of diversity in two contexts. The first is adaptive radiation - the rapid diversification of a lineage into a range of ecologically and phenotypically distinct niche specialists - of which the Galapagos finches and African rift lake cichlids are hallmark examples. We study adaptive radiation in the laboratory using the soil bacterium Pseudomonas fluorescens. Our aim is to understand the mechanisms governing the rate and extent of diversification. The second is the process that underlies diversification itself, adaptation. Our understanding of adaptation has not, until recently, moved much past Darwin's original idea that natural selection is the mechanism responsible. Our work aims to test the most compelling predictions of the increasingly sophisticated theory of adaptation that has developed over the past 10 years. We use the filamentous fungus Aspergillus nidulans for this work as it has a number of unique features that allow us to document adaptive evolution in the laboratory and tease apart the underlying genetic changes responsible. My lab offers outstanding opportunities for training in experimental evolution and allied fields (experimental design, microbiology) and I maintain close links with collaborators who provide complementary expertise for training in quantitative genetics, statistics, modeling and microbial genetics. This work makes some of the oldest and most fundamental problems in biology accessible to experimental research for the first time. I expect the results to be of wide and general interest, contributing to basic knowledge in evolution as well as more applied problems in medicine and conservation biology.