Martian meteorite - Boron could have sparked life on Mars
A Martian meteorite showing veins of clay, which contain high levels of boron, a necessary ingredient for early life. The legend in the bottom right is equal to 1/250 of an inch. Credit:Institute for Astronomy at the University of Hawaii at Manoa
Boron found in a meteorite from Mars may be a sign that a chemical that could have once helped spark life on the Red Planet was once abundant on its alien surface.
Working at the University of Hawaii (UH), researchers have discovered high levels of boron in a Martian meteorite sample which fell to Earth long ago. Boron, once oxidized into the form borate, is one of the essential chemicals for RNA, a critical element of life today. Current theories suggest that life on our own world may have began with RNA alone, before the development of DNA.
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"Borates may have been important for the origin of life on Earth because they can stabilize ribose, a crucial component of RNA. In early life, RNA is thought to have been the informational precursor to DNA," James Stephenson from the University of Hawaii, said.
Stephenson, who is an evolutionary biologist, first came up with the idea for the research while drinking a beer with cosmochemist Lydia Hallis.
"Discussing this with Dr. Hallis, I found out that it was barely studied. I was shocked and excited. She then informed me that both the samples and the specialized machinery needed to analyze them were available at UH," Stephenson said. That machinery included a device called an ion microprobe, which shoots a beam of ions at a sample and measures other ions that are knocked off the substance.
The meteorite itself was found by the Antarctic Search of Meteorites project during their 2009-2010 collection season. Its Martian origin was apparent from its composition, and the clays within its cracks and fissures are thought to be up to 700 million years old. This is far older than any clays found on Earth. The levels of boron found were ten times higher than any known meteorite.
RNA was likely the first mechanism by which genetic information was passed from one generation to another. Today, that RNA is created biologically, in a process dependent on DNA. But before DNA developed, RNA had to form using a different method. One of the critical ingredients needed to make that happen is the sugar ribose. Experiments have shown that given the conditions present on the Earth when life first arose, ribose would be abundant and stable on the Earth - but only in the presence of borate. Having this ingredient on Mars, along with free-flowing water, could have helped to spark life on Mars in the distant past.
Results of the research were published June 6 in the online journal PLOS ONE.