A new method for studying the evolutionary origin of the SAR11 Glade marine bacteria

作者：Zhao Xin; Wan Xiaogeng; He Rong L; Yau Stephen S T

来源：Molecular Phylogenetics and Evolution, 2016, 98: 271-279.

DOI：10.1016/j.ympev.2016.02.015

• Natural vector
• Natural graph representation
• SAR11
• Alphaproteobacteria
• Phylogenetics

The free-living SARI I Glade is a globally abundant group of oceanic Alphaproteobacteria, with small genome sizes and rich genomic A+T content. However, the taxonomy of SAR11 has become controversial recently. Some researchers argue that the position of SAR11 is a sister group to Rickettsiales. Other researchers advocate that SAR11 is located within free-living lineages of Alphaproteobacteria. Here, we use the natural vector representation method to identify the evolutionary origin of the SAR11 Glade. This alignment-free method does not depend on any model assumptions. With this approach, the correspondence between proteome sequences and their natural vectors is one-to-one. After fixing a set of proteins, each bacterium is represented by a set of vectors. The Hausdorff distance is then used to compute the dissimilarity distance between two bacteria. The phylogenetic tree can be reconstructed based on these distances. Using our method, we systematically analyze four data sets of alphaproteobacterial proteomes in order to reconstruct the phylogeny of Alphaproteobacteria. From this we can see that the phylogenetic position of the SAR11 group is within a group of other free-living lineages of Alphaproteobacteria.

• 出版日期2016-5
• 单位清华大学