All five genetic 'letters' of DNA and RNA found in samples from asteroid Ryugu

[Jaguar43]

Scientists have found all the basic building blocks of genetic material in samples from an ancient asteroid. ScienceDaily, republishing an article from The Conversation, reports that Japanese researchers have detected all five nucleobases used in DNA and RNA in samples from asteroid Ryugu

The nucleobases are adenine, guanine, cytosine, thymine and uracil. The samples were collected by JAXA's Hayabusa2 mission and brought back to Earth in 2020, and the work, by researchers including Toshiki Koga, Yasuhiro Oba and Yoshinori Takano, was published in Nature Astronomy

Uracil alone was found in Ryugu samples in 2023, and NASA's samples from asteroid Bennu showed all five in 2025. The ratios differ between bodies, with the Murchison meteorite rich in one type of nucleobase called purines, while Bennu and the Orgueil meteorite lean towards pyrimidines, possibly because of differing amounts of ammonia

Only two samples were tested, and these are ingredients rather than signs of life. The idea that asteroids delivered such molecules to the early Earth remains a hypothesis

Finding the building blocks of genetic material on a 4.5 billion year old asteroid suggests these molecules may be common in the solar system. It adds weight to the idea that life's ingredients could have arrived from space. It is a reminder of how valuable sample return missions are

Could life's ingredients have come from space? And which asteroid or moon should we sample next?

All 5 genetic "letters" of DNA and RNA discovered in a 4.5-billion-year-old asteroidwww.sciencedaily.com

[Eastern Brett]

Sample return missions are worth every penny. Analysing material in labs on Earth reveals so much more than remote instruments. More missions like this please

Mars sample return next. Japan's space programme deserves more credit. Hayabusa missions were remarkable