Which came first, the chicken or the egg? Researchers may have come up with the answer.
Robert Service via AAAS:
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The origin of life on Earth is a set of paradoxes. In order for life to have gotten started, there must have been a genetic molecule—something like DNA or RNA—capable of passing along blueprints for making proteins, the workhorse molecules of life. But modern cells can’t copy DNA and RNA without the help of proteins themselves. To make matters more vexing, none of these molecules can do their jobs without fatty lipids, which provide the membranes that cells need to hold their contents inside. And in yet another chicken-and-egg complication, protein-based enzymes (encoded by genetic molecules) are needed to synthesize lipids.
Now, researchers say they may have solved these paradoxes. Chemists report today that a pair of simple compounds, which would have been abundant on early Earth, can give rise to a network of simple reactions that produce the three major classes of biomolecules—nucleic acids, amino acids, and lipids—needed for the earliest form of life to get its start.