达尔豪斯大学Andrew J. Roger研究小组提出了一棵根结实的真核生物树揭示了它们被发掘的祖先。该项研究成果发表在2025年3月12日出版的《自然》上。

在这里，课题组研究人员基于一个新的、更大的、包括所有已知真核超群的线粒体蛋白质数据集，以前所未有的分辨率估计了eToL的根源。他们对100个分类单元的分析93个具有最先进系统发育模型的蛋白质数据集和对替代假设的广泛评估表明，真核根位于两个多超群组合之间：“Opimoda+”和“Diphoda+”。这一立场在不同的模型和稳定性分析中得到一致的支持。值得注意的是，包含“典型挖掘”的组位于根的两侧，这表明“挖掘”细胞结构的复杂特征可以追溯到LECA。这项研究揭示了现存真核生物起源的祖先细胞，并为研究典型真核生物特征的起源和进化提供了一个重要的框架。

据了解，真核生物生命树（eToL）描述了所有真核生物之间的关系；它的根代表了最后的真核共同祖先（LECA），所有现存的复杂生命形式都是从这个祖先进化而来的。定位这一根对于重建LECA的特征至关重要，既是真核发生的终点，也是支撑真核生物多样化的无数复杂特征进化的起点。然而，由于进化模型不完善、分类群采样不足和系统发育信号有限等原因，普遍存在系统发育伪象，因此根的位置仍然存在争议。

附：英文原文

Title: A robustly rooted tree of eukaryotes reveals their excavate ancestry

Author: Williamson, Kelsey, Eme, Laura, Baos, Hector, McCarthy, Charley G. P., Susko, Edward, Kamikawa, Ryoma, Orr, Russell J. S., Muoz-Gmez, Sergio A., Minh, Bui Quang, Simpson, Alastair G. B., Roger, Andrew J.

Issue&Volume: 2025-03-12

Abstract: The eukaryote Tree of Life (eToL) depicts the relationships among all eukaryotic organisms; its root represents the Last Eukaryotic Common Ancestor (LECA) from which all extant complex lifeforms are descended1. Locating this root is crucial for reconstructing the features of LECA, both as the endpoint of eukaryogenesis and the start point for the evolution of the myriad complex traits underpinning the diversification of living eukaryotes. However, the position of the root remains contentious due to pervasive phylogenetic artefacts stemming from inadequate evolutionary models, poor taxon sampling and limited phylogenetic signal1. Here we estimate the root of the eToL with unprecedented resolution on the basis of a new, much larger, dataset of mitochondrial proteins that includes all known eukaryotic supergroups. Our analyses of a 100 taxon×93 protein dataset with state-of-the-art phylogenetic models and an extensive evaluation of alternative hypotheses show that the eukaryotic root lies between two multi-supergroup assemblages: ‘Opimoda+’ and ‘Diphoda+’. This position is consistently supported across different models and robustness analyses. Notably, groups containing ‘typical excavates’ are placed on both sides of the root, suggesting the complex features of the ‘excavate’ cell architecture trace back to LECA. This study sheds light on the ancestral cells from which extant eukaryotes arose and provides a crucial framework for investigating the origin and evolution of canonical eukaryotic features.

DOI: 10.1038/s41586-025-08709-5

Source: https://www.nature.com/articles/s41586-025-08709-5