Genetic Blueprint Pieces Found in Asteroids
The final two nucleobases — cytosine and thymine — were recently discovered in meteorites using new extraction and analysis techniques.
This is another story where I again have to stipulate that I am not a biologist, so apologies if we trip over that aspect of the science at some point.
In a new paper published in Nature Communications and led by Yasuhiro Oba, scientists have revealed that the last two informational units of life’s building blocks — DNA and RNA — have finally been found in meteorites. This means that all five of those units have now been discovered in rocks that come from space.
The five components are nucleobases, which belong to classes of organic molecules and have a pretty big variety. And the last two bases — cytosine and thymine (the C and T of DNA pairs) — took this long to find because of their more delicate structures. Those structures may have degraded using previous the previous sampling technique, which, I have to admit, is kind of cool. And here I quote from the press release: In the earlier experiments, scientists created something of a “meteorite tea,” placing grains of meteorite in a hot bath to let the molecules on the sample extract into the solution and then analyzed the molecular makeup of the extraterrestrial broth.
The newer sampling technique used cool water extraction instead of hot formic acid, preventing the destruction of the more delicate molecules. And the instrumentation has improved, becoming more sensitive and able to find smaller amounts of the molecules.
Now, none of this means there is life on asteroids, and it doesn’t prove that asteroid impacts seeded life on Earth somehow. It does give scientists more molecules to use in lab experiments designed to understand just how life came about here on Earth. Co-author Jason Dworkin sums the work up thusly: This is adding more and more pieces; meteorites have been found to have sugars and bases now. It’s exciting to see progress in the making of the fundamental molecules of biology from space.
And maybe they can use this new technique on those samples due back from Bennu.
More Information
NASA press release
All of the bases in DNA and RNA have now been found in meteorites (Science News)
“Identifying the wide diversity of extraterrestrial purine and pyrimidine nucleobases in carbonaceous meteorites,” Yasuhiro Oba et al., 2022 April 26, Nature Communications
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