last eukaryotic common ancestor (LECA) Archives - Astrobiology

Reconstruction of the ancestral LECA proteome and its metabolic features

Genomics, Proteomics, Bioinformatics, Nomenclature, Systematics, Natural History, Origin & Evolution of Life, Press Release

Rethinking The Origin Of Our Cells As A Story Of Microbial Alliances

by Keith CowingJune 13, 2026June 13, 2026

All cells in animals, plants, fungi, and protists share a fundamental characteristic: they are eukaryotic cells—complex cells with specialized internal compartments. The cells that make up our bodies are no […]

Inferred subcellular organization in LECA, the last eukaryotic common ancestor, based on its estimated gene content. Credit Cell illustration adapted from multiple graphics shared as open source by SwissBioPics.

Biophysics, Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Microbiology & Virology, Nanotechnology & SynBio, Origin & Evolution of Life, Press Release

Scientists Reveal Disease Genes From Reconstruction Of Ancestor To All Complex Life

by Keith CowingMay 28, 2026May 28, 2026

A University of Texas at Austin-led team has reconstructed the most detailed map to date of the molecular machines that carried out the functions of life in an ancient ancestor […]

Relationship between total group age T and crown group age tcg across various diversification rates λ − µ, equation 4. The heatmap represents the crown group age for a given rate and total group age (isolines are presented for reference). The orange dot-dashed line is the minimum value for T to fit the observed eukaryotic-grade fossil record of the late Palaeoproterozoic (1780 Ma), the red-dashed isoline is the minimum age for tcg fitting the observed crown-eukaryote fossil record from the end of the Mesoproterozoic (1050 Ma), and the grey interval is the range of possible tcg require to obtain the living diversity for a given rate and total age. The isolines for late LECA (tcg = 1200) or generous late LECA (tcg = 1400 Ma) are the red-dotted lines. -- biorxiv.org

Biosignatures & Paleobiology, Fossils & Paleontology, Genomics, Proteomics, Bioinformatics, Habitable Zones, Microbiology & Virology, Origin & Evolution of Life, Sample Return, Status Report

Clade Dynamics Support An Early Origin Of Crown Eukaryotes

by Keith CowingApril 7, 2026April 7, 2026

The timing of the last eukaryotic common ancestor (LECA) remains a fundamental question in evolutionary biology and palaeontology. Unambiguous eukaryotic-grade fossils appear from 1780 Ma, but no crown-group supergroups are […]

Iron disruption through endosymbiosis: An overview of disruptive effects of iron throughout endosymbiosis, from ecological associations and biochemistries of archaea and bacteria (69) to LECA (90, 94). These effects may underlie a mechanistic connection between the cessation of marine iron deposition and the radiation of the earliest eukaryotes. -- biorxiv.org

Biogeochemical Cycles & Geobiology, Biophysics, Biosignatures & Paleobiology, Origin & Evolution of Life, Status Report

Did Iron Suppress Eukaryote Emergence and Early Radiation?

by Keith CowingFebruary 5, 2026June 11, 2026

The last eukaryotic common ancestor (LECA) is widely thought to have been an oxygen-respiring organism, arising through endosymbiosis when a free-living bacterium became the mitochondrion.

Simplified EPOC generation and processing pipeline

Genomics, Proteomics, Bioinformatics, Microbiology & Virology, Origin & Evolution of Life, Status Report

Dominant Contribution Of Asgard Archaea To Eukaryogenesis

by Keith CowingJanuary 26, 2026January 26, 2026

The origin of eukaryotes is one of the key problems in evolutionary biology. The demonstration that the last eukaryotic common ancestor (LECA) already contained the mitochondrion—an endosymbiotic organelle derived from […]

Biochemical requirements and toxicities for oxygen, iron and sulfide restrict conditions for endosymbiosis: Iron, sulfide and oxygen readily react with one another, leading to reservoir fluctuations that characterize Paleoproterozoic marine chemistry. A narrower set of interactive conditions involving these three chemicals (dotted box) are circumscribed by the context of cellular homeostatic constraints, which differ among organisms. Iron is biphasic: it is essential at lower cellular concentrations but toxic at higher cellular concentrations. Iron and oxygen homeostatic constraints must have been operable within archaea and bacteria across the process of endosymbiosis, up to and including full endogenization of the mitochondrion into a eukaryotic organelle. -- biorxiv.org

Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Microbiology & Virology, Origin & Evolution of Life, Status Report

Did Iron Suppress Eukaryote Emergence and Early Radiation?

by Keith CowingJune 29, 2025June 28, 2025

The last eukaryotic common ancestor (LECA) is widely thought to have been an oxygen-respiring organism, arising through endosymbiosis when a free-living bacterium became the mitochondrion.