Lozupone Catherine A, Knight Rob
Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
Proc Natl Acad Sci U S A. 2007 Jul 3;104(27):11436-40. doi: 10.1073/pnas.0611525104. Epub 2007 Jun 25.
Microbes are difficult to culture. Consequently, the primary source of information about a fundamental evolutionary topic, life's diversity, is the environmental distribution of gene sequences. We report the most comprehensive analysis of the environmental distribution of bacteria to date, based on 21,752 16S rRNA sequences compiled from 111 studies of diverse physical environments. We clustered the samples based on similarities in the phylogenetic lineages that they contain and found that, surprisingly, the major environmental determinant of microbial community composition is salinity rather than extremes of temperature, pH, or other physical and chemical factors represented in our samples. We find that sediments are more phylogenetically diverse than any other environment type. Surprisingly, soil, which has high species-level diversity, has below-average phylogenetic diversity. This work provides a framework for understanding the impact of environmental factors on bacterial evolution and for the direction of future sequencing efforts to discover new lineages.
微生物难以培养。因此，关于一个基本进化主题——生命多样性的主要信息来源是基因序列的环境分布。我们基于从111项对不同物理环境的研究中汇编的21752个16S rRNA序列，报告了迄今为止对细菌环境分布最全面的分析。我们根据样本中所含系统发育谱系的相似性对样本进行聚类，结果令人惊讶地发现，微生物群落组成的主要环境决定因素是盐度，而非温度、pH值的极端情况，或我们样本中所代表的其他物理和化学因素。我们发现沉积物在系统发育上比其他任何环境类型都更加多样。令人惊讶的是，具有高物种水平多样性的土壤，其系统发育多样性却低于平均水平。这项工作为理解环境因素对细菌进化的影响以及未来发现新谱系的测序工作方向提供了一个框架。
