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Luca

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One Genetic Code, Two Beginnings: A Fresh Take on Life’s Origins
science11 days ago

One Genetic Code, Two Beginnings: A Fresh Take on Life’s Origins

A Science Advances study argues bacteria and archaea inherited one ancient genetic code but independently completed cellular metabolism, effectively yielding one origin of the genetic code and two origins of life. The model suggests LUCA relied on environmental chemistry and metals to drive core reactions, with each lineage later filling in missing metabolism with its own enzymes. Five cases of convergent, structurally distinct enzymes underlie these separate paths. The idea is provocative and tentative, contingent on more archaeal genomes and experiments, and does not imply two abiogenesis events—merely two autonomous metabolic completions after a shared genetic root.

via Space Daily|
#convergent-evolution#hydrothermal-vents#luca
Early metabolism reveals dual origins of life on Earth
science12 days ago

Early metabolism reveals dual origins of life on Earth

Researchers mapped the full early metabolism network (420 reactions) and found that bacteria and archaea likely shifted to free-living cells independently, with LUCA possessing only about half of metabolic reactions while the rest were catalyzed by environmental metals; the study suggests a hybrid early metabolism combining metal catalysts and enzymes and proposes a pre-ATP energy source via phosphite reacting with palladium in hydrothermal-vent environments.

via ScienceDaily|
#archaea#bacteria#luca
LUCA Dates Back 4.2 Billion Years, Rewriting the Story of Life
science13 days ago

LUCA Dates Back 4.2 Billion Years, Rewriting the Story of Life

New analysis places LUCA—the Last Universal Common Ancestor—on Earth about 4.2 billion years ago, roughly 400 million years after Earth's formation, based on genetic mutation rates and shared cellular machinery. The study suggests LUCA was a simple prokaryote with an immune system and likely lived in a recycling microbial ecosystem, meaning all modern life traces back to this ancient ancestor, while the exact path from LUCA to later life remains to be fully understood.

via Yahoo|
#biology#evolution#last-universal-common-ancestor
Two Separate Beginnings: Study Finds Bacteria and Archaea Metabolism Emerged Independently
science20 days ago

Two Separate Beginnings: Study Finds Bacteria and Archaea Metabolism Emerged Independently

A Science Advances study proposes life on Earth may have arisen twice, with bacteria and archaea independently evolving metabolism before LUCA, suggesting two roots of life rather than a single lineage; enzymes may have been preceded by environmental metals and four catalytic phases led proto-cells to free-living status after their split.

via ScienceAlert|
#archaea#bacteria#luca
Amino Acids Entered Life's Code in Multiple Ways, Scientists Say
science1 month ago

Amino Acids Entered Life's Code in Multiple Ways, Scientists Say

A University of Arizona-led analysis rethinking the origin of life suggests the 20 canonical amino acids may have entered the genetic code from multiple abiotic routes rather than a single sequential order. Building on a 2024 PNAS study of protein domains in LUCA, newer work shows amino acids could originate from diverse early-Earth chemistry and that core cellular machinery can function with a reduced amino‑acid alphabet in engineered cells. This challenges the view that tryptophan was the last amino acid added and has implications for our understanding of early protolife on Earth and the search for life elsewhere, including oceans on Enceladus.

via Yahoo|
#amino-acids#enceladus#genetic-code
LUCA Existed 4.2 Billion Years Ago, Immune System Included, Redrawing Life’s Origins
science3 months ago

LUCA Existed 4.2 Billion Years Ago, Immune System Included, Redrawing Life’s Origins

New analysis pushes LUCA, the Last Universal Common Ancestor of all life, to about 4.2 billion years ago—roughly 400 million years after Earth formed—suggesting life began very early on our planet. The study reconstructs LUCA as a simple prokaryote that already had an immune system, implying primordial viruses were at play and that early microbes formed a recycling ecosystem with organisms like methanogens, offering new insight into how life evolved from its origins.

via Yahoo|
#42-billion-years-ago#early-life#immunity
Ancient Microbes May Have Emerged in Earth's Harsh Hadean Era
science4 months ago

Ancient Microbes May Have Emerged in Earth's Harsh Hadean Era

New geochemical data and molecular-clock analysis suggest life could have arisen during Earth's fiery Hadean period, about 4.4–4.2 billion years ago, with LUCA as the Last Universal Common Ancestor and LECA leading to modern eukaryotes; evidence points to liquid water despite extreme conditions, and ongoing genome recovery efforts may further refine when these ancestral stages appeared.

via indiandefencereview.com|
#hadean#leca#luca
Amino Acids May Have Arrived Out of Order, Rewriting Life's Origins
science6 months ago

Amino Acids May Have Arrived Out of Order, Rewriting Life's Origins

A University of Arizona study published in PNAS suggests the first amino acids did not appear in a simple, global sequence as traditionally thought. By analyzing the evolution of protein domains dating to LUCA, researchers find that tryptophan was more common in pre-LUCA life than post-LUCA, implying a more complex and regionally diverse origin of amino acids and a potentially ancient, diverse genetic code. These results challenge established timelines for life's beginnings and hint that amino acids could form in non-Earth environments, widening the search for extraterrestrial life (e.g., Enceladus' subsurface ocean).

via Indian Defence Review|
#aminoacids#geneticcode#luca
Scientists Discover Earth's Oldest Common Ancestor, Redefining Life's Origins
science8 months ago

Scientists Discover Earth's Oldest Common Ancestor, Redefining Life's Origins

Scientists have identified the last universal common ancestor (LUCA) of all life on Earth, dating it to around 4.2 billion years ago. LUCA was a complex, cellular organism that thrived in hot, oxygen-free environments using hydrogen-based metabolism and had early immune systems, indicating rapid evolution of life shortly after Earth's formation.

via The Brighter Side of News|
#early-earth#genome-reconstruction#luca