RNA World to Molecular Evolution: Origins of Life in Prebiotic Earth
RNA's Role in Life's Origins
Recent experiments strengthen the RNA world hypothesis, suggesting that life on Earth began with self-replicating RNA molecules rather than DNA. Researchers discovered that RNA could have formed approximately 4.3 billion years ago, just 200 million years after Earth's creation. This timing aligns perfectly with the earliest evidence of life found in ancient zircon deposits, making RNA a prime candidate for life's molecular ancestor.
The Giant Impact Theory
Scientists propose that a massive 500-kilometer-wide protoplanet impact delivered RNA's building blocks to our planet. The presence of borates in early Earth's environment didn't hinder RNA formation; instead, these compounds stabilized crucial ribose molecules and facilitated phosphate production. This discovery reshapes our understanding of how life's fundamental molecules assembled under prebiotic conditions.
Evolution at the Molecular Level
New research reveals that RNA enzymes can accurately copy other functional RNA strands while generating molecular variants. This capability suggests Darwinian evolution occurred at the molecular scale before complex cells emerged. These findings bring scientists closer to recreating RNA-based life in laboratories, potentially unlocking the secrets of life's emergence on Earth and beyond.
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