![Bold black letters illustrate amino acids that are deduced as early by the approach, while red letters indicate late additions to the alphabet according to the approach (C* implies possible prebiotic synthesis under specific and narrow conditions [4]). Regular black letters represent amino acids that have not been resolved as either early or late by the approach. LUCA: last universal common ancestor; LECA: last eukaryotic common ancestor; rTCA: tricarboxylic acid cycle. -- Trends in Genetics](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Reconstructing.png?resize=1200%2C720&ssl=1)
[Trends in Genetics] The canonical amino acid alphabet has remained remarkably stable since life’s early stages, yet the factors that shaped its emergence remain debated. Early views emphasized prebiotic availability […]
tricarboxylic acid cycle
Posted inAtmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Habitable Zones, Microbiology & Virology, Press Release, ROVs/Submersibles/Diving, Sample Return, Water/Hycean Worlds & Oceanography
How Microbes Use Earth’s Ancient Carbon
Hydrothermal vents on the ocean floor release carbon dioxide that is many million years old. This old carbon originates from the Earth’s interior, and it escapes either directly from the […]
Posted inBiochemistry & Organic Chemistry, Genomics, Proteomics, Bioinformatics, Origin & Evolution of Life, Status Report
From Amino Acids to α-Keto Acids via β-Elimination and Transamination Initiates a Pathway to Prebiotic Reaction Networks
α-Keto acids, such as pyruvate and glyoxylate, may have been critical in generating reaction networks at the origins of life due to their facile carbon-carbon bond formation and their hydrolytic […]
Posted inBiochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Genomics, Proteomics, Bioinformatics, Habitable Zones, Icy Worlds, Status Report, Water/Hycean Worlds & Oceanography
Thermodynamic Constraints On The Citric Acid Cycle And Related Reactions In Ocean World Interiors
Icy ocean worlds attract significant interest for their astrobiological potential due to subsurface oceans, organics, and chemical energy sources.