英国布里斯托大学Tom A. Williams、白俄罗斯维捷布斯克国立马舍洛夫大学Gergely J. Szöllsi和英国昆士兰大学Philip Hugenholtz团队合作取得一项新突破。他们研究表明根基系统发育可解决早期细菌进化。相关论文发表在2021年5月7日出版的《科学》杂志上。

研究人员对11272个基因家族的进化过程进行建模，以确定其根基、水平基因转移（HGT）的程度以及最后一个细菌祖先（LBCA）的性质。研究分析表明根基在主要进化枝菌属和Gracilicutes之间的进化树上，表明LBCA是一种自由生活的鞭毛状、杆状双膜生物。

与最近的研究相反，研究人员的分析推翻了候选Phyla辐射的基础位置，而该位置将姊妹分支到了Terrabacteria中的Chloroflexota。 虽然大多数基因家族（92％）具有HGT特征，但总体而言，三分之二的基因传递是垂直的，这表明进化树为解释细菌的进化提供了有意义的参考结构。

研究人员表示，细菌进化树的根基是了解早期进化所必需的，但是对根基的位置存在争议。

附：英文原文

Title: A rooted phylogeny resolves early bacterial evolution

Author: Gareth A. Coleman, Adrián A. Davín, Tara A. Mahendrarajah, Lénárd L. Szánthó, Anja Spang, Philip Hugenholtz, Gergely J. Szllsi, Tom A. Williams

Issue&Volume: 2021/05/07

Abstract: A rooted bacterial tree is necessary to understand early evolution, but the position of the root is contested. Here, we model the evolution of 11,272 gene families to identify the root, extent of horizontal gene transfer (HGT), and the nature of the last bacterial common ancestor (LBCA). Our analyses root the tree between the major clades Terrabacteria and Gracilicutes and suggest that LBCA was a free-living flagellated, rod-shaped double-membraned organism. Contrary to recent proposals, our analyses reject a basal placement of the Candidate Phyla Radiation, which instead branches sister to Chloroflexota within Terrabacteria. While most gene families (92%) have evidence of HGT, overall, two-thirds of gene transmissions have been vertical, suggesting that a rooted tree provides a meaningful frame of reference for interpreting bacterial evolution.

DOI: 10.1126/science.abe0511

Source: https://science.sciencemag.org/content/372/6542/eabe0511