Phylogeny and ecology of ciliated protozoa

我研究纤毛虫原生动物，常见的单细胞微生物在湖泊和海洋，土壤和森林垃圾，并在小池塘。纤毛虫以细菌和小型原生生物为食。纤毛虫被幼鱼和小甲壳类动物吃掉，然后可能被大鱼吃掉。因此，纤毛虫是食物网中的营养环节，了解它们在这些生态系统中的作用非常重要。我的研究计划的一个方面是实验生态学。我们已经建立了一个名为Limnotron的研究设施，我们将能够组装不同复杂性的生态系统，其中一些是纤毛虫和其他单细胞生物。通过这种方式，我们可以开始了解它们在维持生态系统稳定等方面的生态重要性。纤毛虫可能有超过30，000种，但我们对其物种多样性和地理分布的了解状况阻碍了我们了解它们的生态作用。例如，不同的物种可能具有非常不同的生态作用，因此正确的物种识别是任何生态研究的关键第一步。因此，我的研究的第二个主要目标是开发分子方法，如DNA条形码，使我们能够操作性地评估生物多样性和分布。对纤毛虫多样性的理解导致了第三个主要目标：构建该群体的进化历史或进化史，并建立现代分类。今天的系统发育分析使用基因序列，如核糖体基因，这是高度保守的所有生命形式。通过比较这些基因序列，物种之间相互关联，这些基因序列比纤毛虫的显微形态更相似。然而，核糖体基因并没有为我们提供足够的信息，因此我将使用多个基因来增加特征信息，并提供更可靠的结论。由于我是加拿大唯一一位研究这些生物的专家，也是世界上为数不多的专家之一，我经常与世界各地的同事合作描述新物种。

I study the ciliated protozoa, common unicellular microorganisms found in lakes and oceans, in soils and forest litter, and in small ponds. Ciliates feed on bacteria and smaller protists. Ciliates are eaten by larval fish and small crustaceans that may then be eaten by larger fish. Thus, ciliates are trophic links in food webs, and it is important to understand their roles in these ecosystems. One aspect of my research program is experimental ecology. We have built a research facility called the Limnotron in which we will be able to assemble ecosystems of varying complexity, some of them with ciliates and other unicellular organisms. In this way, we can begin to understand their ecological importance in, for example, maintaining ecosystem stability. There may be over 30,000 species of ciliates, but the state of our knowledge of their species diversity and geographic distributions presents a barrier to understanding their ecological role. For example, different species may have very different ecological roles so correct species identification is a critical first step in any ecological study. Thus, a second major goal of my research is to develop molecular methods, such as DNA barcodes, to enable us to operationally assess biodiversity and distribution. An understanding of ciliate diversity leads to a third major goal: construction of both the evolutionary history or phylogeny of the group and establishment of a modern classification. Today phylogenetic analyses use gene sequences, such as ribosomal genes, which are highly conserved across all life forms. Species are related to each other by comparing these gene sequences, which are more similar to each other than the microscopic morphology of ciliates. Ribosomal genes however are not providing us with sufficient information, and so I will use multiple genes to increase the character information and provide more robust conclusions. Since I am the only expert on these organisms in Canada and one of the few in the world, I often collaborate with colleagues around the world to describe new species.