An Alternative Root for the Eukaryote Tree of Life

• The root of the eukaryote tree of life defines some of the most fundamental relationships among species. It is also critical for defining the last eukaryote common ancestor (LECA), the shared heritage of all extant species. The unikont-bikont root has been the reigning paradigm for eukaryotes for more than 10 years but is becoming increasingly controversial. We developed a carefully vetted data set, consisting of 37 nuclear-encoded proteins of close bacterial ancestry (euBacs) and their closest bacterial relatives, augmented by deep sequencing of the Acrasis kona (Heterolobosea, Discoba) transcriptome. Phylogenetic analysis of these data produces a highly robust, fully resolved global phy- logeny of eukaryotes. The tree sorts all examined eukaryotes into three megagroups and identifies the Discoba, and potentially its parent taxon Excavata, as the sister group to the bulk of known eukaryote diversity, the proposed Neozoa (Amorphea + Stramenopila+Alveolata+Rhizaria+ Plantae [SARP]). All major alternative hypotheses are rejected with as little as w50% of the data, and this resolu- tion is unaffected by the presence of fast-evolving alignment positions or distant outgroup sequences. This ‘‘neozoan- excavate’’ root revises hypotheses of early eukaryote evolution and highlights the importance of the poorly stud- ied Discoba for understanding the evolution of eukaryotic diversity and basic cellular processes. 

Ämnesord

NATURVETENSKAP  -- Biologi -- Biologisk systematik (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biological Systematics (hsv//eng)

NATURVETENSKAP  -- Biologi -- Evolutionsbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Evolutionary Biology (hsv//eng)

NATURVETENSKAP  -- Data- och informationsvetenskap -- Bioinformatik (hsv//swe)

NATURAL SCIENCES  -- Computer and Information Sciences -- Bioinformatics (hsv//eng)

Nyckelord

Eukaryote root

molecular phylogenetics

phylogenetics

Biologi med inriktning mot evolutionär organismbiologi

Biology with specialization in Evolutionary Organismal Biology

Biology with specialization in Molecular Evolution

Biologi med inriktning mot molekylär evolution

Biologi med inriktning mot systematik

Biology with specialization in Systematics

Publikations- och innehållstyp

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