不断扩张的阿斯加德古菌及其与真核生物难以捉摸的关系。
The expanding Asgard archaea and their elusive relationships with Eukarya.
作者信息
Da Cunha Violette, Gaïa Morgan, Forterre Patrick
机构信息
CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC) Université Paris-Saclay Gif-sur-Yvette France.
Génomique Métabolique, Génoscope, Institut François Jacob, CEA, CNRS Univ. Evry, Université Paris-Saclay Evry France.
出版信息
mLife. 2022 Mar 24;1(1):3-12. doi: 10.1002/mlf2.12012. eCollection 2022 Mar.
The discovery of Asgard archaea and the exploration of their diversity over the last 6 years have deeply impacted the scientific community working on eukaryogenesis, rejuvenating an intense debate on the topology of the universal tree of life (uTol). Here, we discuss how this debate is impacted by two recent publications that expand the number of Asgard lineages and eukaryotic signature proteins (ESPs). We discuss some of the main difficulties that can impair the phylogenetic reconstructions of the uTol and suggest that the debate about its topology is not settled. We notably hypothesize the existence of horizontal gene transfers between ancestral Asgards and proto-eukaryotes that could result in the observed abnormal behaviors of some Asgard ESPs and universal marker proteins. This hypothesis is relevant regardless of the scenario considered regarding eukaryogenesis. It implies that the Asgards were already diversified before the last eukaryotic common ancestor and shared the same biotopes with proto-eukaryotes. We suggest that some Asgards might be still living in symbiosis today with modern Eukarya.
过去6年里阿斯加德古菌的发现及其多样性探索,对从事真核生物起源研究的科学界产生了深远影响,重新引发了关于生命之树(uTol)拓扑结构的激烈争论。在此,我们讨论这一争论如何受到最近两篇扩大了阿斯加德谱系和真核生物特征蛋白(ESP)数量的论文的影响。我们讨论了一些可能妨碍生命之树系统发育重建的主要困难,并表明关于其拓扑结构的争论尚未解决。我们特别推测,在祖先阿斯加德古菌和原真核生物之间存在水平基因转移,这可能导致一些阿斯加德ESP和通用标记蛋白出现异常行为。无论考虑何种真核生物起源的情况,这一假设都具有相关性。这意味着阿斯加德古菌在最后一个真核生物共同祖先出现之前就已经多样化,并与原真核生物共享相同的生态位。我们认为,如今一些阿斯加德古菌可能仍与现代真核生物共生。