X post claims DNA, RNA bases in meteorites

An X post circulating on May 21 said scientists had found all the bases used in DNA and RNA in meteorites. That claim is broadly consistent with published research, but it is not new. NASA said in an April 26, 2022 article that an international team led by Yasuhiro Oba of Hokkaido University had identified the final two missing nucleobases — cytosine and thymine — in carbonaceous meteorites, completing the set of five used in life on Earth. The five canonical nucleobases are adenine, guanine, cytosine, thymine and uracil. DNA uses adenine, guanine, cytosine and thymine, while RNA uses adenine, guanine, cytosine and uracil. Before the 2022 study, NASA said scientists had found only three of the five in extraterrestrial samples. ### Did scientists really find all five bases in meteorites? (nasa.gov) Nature Communications published the 2022 paper reporting nucleobases in three carbonaceous meteorites. The paper said researchers identified purine and pyrimidine nucleobases including cytosine, uracil and thymine, alongside adenine and guanine that had been reported earlier. NASA said the newly identified pair, cytosine and thymine, had eluded earlier searches, and co-author Danny Glavin said, “We now have evidence that the complete set of nucleobases used in life today could have been available on Earth when life emerged.” (nasa.gov) ### Why did this resurface now? A March 2026 Nature Astronomy paper reported all five canonical nucleobases in samples returned from the C-type asteroid Ryugu by Japan’s Hayabusa2 mission. (nature.com) That study compared the asteroid results with meteorites including Murchison and Orgueil, according to the journal summary. NASA also said in December 2025 that “all five nucleobases used to construct both DNA and RNA” had already been found in samples from asteroid Bennu returned by the OSIRIS-REx mission. (nasa.gov) That means the broader line of evidence now includes both meteorites recovered on Earth and pristine asteroid-return samples. ### Does this mean life came from space? (nature.com) NASA said in 2022 that the finding does not mean DNA itself formed in a meteorite. The agency said the result showed that genetic components were available for delivery to early Earth and “could have contributed” to the development of biological molecules. The Bennu update made the same distinction. NASA said sugars and nucleobases in asteroid material are “not evidence of life,” but show that building blocks of biological molecules were widespread in the solar system. (nasa.gov) ### What did researchers do differently? The 2022 NASA account said earlier studies often used a hot-acid extraction process described as a kind of “meteorite tea.” NASA said cytosine and thymine are relatively fragile and may have degraded under those older methods. (nasa.gov) The 2022 study instead used more sensitive analytical techniques and gentler extraction, according to NASA and the paper summary. (nasa.gov) Those methods allowed researchers to detect trace amounts of compounds that had likely been missed before. ### So how should readers read the viral post? The May 21 post points to a real scientific result, but it compresses several years of work into a single fresh-sounding claim. (nasa.gov) The meteorite finding dates to April 2022, while later studies on Ryugu and Bennu extended the evidence using returned asteroid samples. Nature Astronomy’s Ryugu paper and NASA’s Bennu updates are the next places to look for the newest primary-source reporting on this question. (science.gsfc.nasa.gov) (nature.com) (nasa.gov)