Genetic molecules provide the ability to store and replicate information and may have been critical for the origin of life, but it is unclear how they arose from complex chemical environments that existed on early Earth. New findings, published this week in the journal Scientific Reports, suggest the answer may start with nitrogen heterocycles, ringed molecules believed to be common on young Earth and elsewhere in the solar system. Several types of heterocycles serve as nucleobases, or subunits, of DNA and RNA, the genetic molecules used by life as we know it.
"One of the challenges of studying the origin of life is deciphering what reactions were key steps," said Christopher House, professor of geosciences at Penn State. "Our work here identified the most likely next steps these molecules could and would take."
Team - Researchers - Heterocycles - Building - Blocks
A team of researchers found that nitrogen heterocycles may have served as building blocks toward life in a series of tests that generated complex chemical mixtures like those possibly created by lightning strikes passing through early Earth's atmosphere. Dozens of different heterocycles produced similar primitive genetic precursors even when the atmospheric composition was varied in the study.
"The real surprises were that so many different such ringed molecules were found to be reactive and that they formed the same next step regardless of what simulated atmosphere we used," said House, who also serves as director of the Penn State Astrobiology Research Center and the NASA Pennsylvania Space Grant Consortium.
Results - Hypothesis - Structures - Formation - DNA
The results support a hypothesis that simpler genetic structures could predate the formation of DNA and RNA and suggest that similar prebiotic reactions could happen elsewhere...
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