‘Before Oxygen, before us’: This microbe may be the root of all life on Earth

Produced by: Manoj Kumar

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Ancient Ancestor

LUCA—the Last Universal Common Ancestor—may have lived 4.2 billion years ago, just 400 million years after Earth formed.

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Genetic Timepiece

Researchers used molecular clocks and fossil-calibrated timelines to rewind evolution and date LUCA’s emergence with precision.

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Complex Origins

LUCA wasn’t basic—it likely had DNA, ribosomes, and ATP metabolism. A cell more advanced than anyone expected.

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Early Immunity

Even at that ancient age, LUCA may have battled viruses, suggesting immune-like defenses existed from the dawn of life.

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Extreme Beginnings

Hydrothermal vents likely hosted LUCA’s world—high pressure, high heat, and chemical-rich waters fueled life’s first spark.

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Ecological Spark

LUCA’s waste was likely fuel for other microbes. These recycling interactions may mark Earth’s earliest ecosystem.

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Rapid Life

If life appeared so soon after Earth formed, it hints that biology may emerge easily on other Earth-like planets.

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Cross-Lineage Clues

Scientists used gene-tree reconciliation, tracking ancient gene swaps to reconstruct LUCA’s life with unprecedented clarity.

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Living Legacy

Though long gone, LUCA’s biological toolkit survives in every living thing today—a silent blueprint etched into life’s DNA.

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