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Another Crucial Building Block of Life Found on Martian Meteorite

Where there's boron, there may be RNA. Where there's RNA, there could be life.
Mars, as seen by the Viking 1 lander in 1977. via

Every once in a while, a rock manages to excite lay people as much as it excites geologists. There’s another such rock in our midst. A meteorite of Martian origin, previously recovered by scientists in Antarctica, has just been found to hold boron, a chemical that biochemists suspect played a key role in the development of RNA. And RNA is thought to have been an essential step in life’s genesis on Earth.

RNA, short for ribonucleic acid, is one of the two types of nucleic acids found in all cells. The other is deoxyribonucleic acid, commonly known as DNA. RNA transmits genetic information from DNA to proteins produced by the cell, making it one of the vital pieces of cellular life. But beyond this role, RNA is thought to have played an essential role in early life on Earth. RNA likely appeared first, giving rise to the DNA that became the first living thing.

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There are three main components that make up RNA: there’s a phosphate; a ribose, a five-carbon sugar central to a cell’s metabolism; and a nucleobase. Both phosphates and nucleobases have been found in meteorites previously, but ribose has never been found beyond Earth. Which makes it the tricky bit. Scientist have yet to explain just how it could have appeared naturally.

But in 2004 chemist Steven Benner, of the Foundation for Applied Molecular Evolution in Gainesville, Florida, had an idea. Boron might be the secret ingredient in RNA’s ribose. It has the unique ability, thanks to it’s size, to stabilize ribose. So evidence of ancient boron could predict ribose and RNA.

Finding boron in a rock from Mars suggests there might have been RNA on the Red Planet. If we apply the Earthly model of the genesis of life (which scientists are wont to do, for lack of any other comparison point) and assume RNA formed before any kind of life, boron could be the element responsible for the ribose that makes up RNA. And from there, the RNA could make DNA, and that means life.

A diagram comparing RNA and DNA, via

Benner’s idea caught the attention of James Stephenson, a biologist from NASA’s Astrobiology Institute at the University of Hawaii. Stephenson found that no one had looked for boron in Martian meteorites, so he prepared and oversaw the study. And he found it. In the final hours of a four day investigation, his team found significant traces of boron – concentrations jumped up from 2 to 3 parts per million up to 200 parts per million – in rocks from Mars.

Up next for Stephenson’s team is more research. They are going to test whether Earth clay with the same amount and configuration of boron that they found in the meteorite can actually stabilize ribose enough to give rise to RNA.

If it turns out that boron can stabilize ribose, it will be a significant addition to the mounting evidence that Mars could once have supported life. Combined with the recent discovery of past water and a long-lost, abundant atmosphere on Mars, it’s looking increasingly like Mars was once a livable planet for some kind of life.

Of course, we always have to remember that just because a planet can harbor life doesn’t mean it did, does, or will in the future. It’s possible boron on Mars never stabilized any ribose. Still, it’ll be pretty neat if it turns out that young Mars and young Earth had the same early environment. The earliest Earth life could have had a Martian twin that never got to grow up.