The discovery of all five nucleobases on Ryugu strengthens the idea that life’s molecular ingredients formed in space before reaching Earth.
A new study reports that samples from the asteroid Ryugu contain all five fundamental nucleobases, the molecular “letters” of life.
Tiny asteroid grains can preserve chemical clues about the ingredients that may have helped life emerge on Earth. The Ryugu material was returned from space in 2020 by the Japan Aerospace Exploration Agency’s (JAXA) Hayabusa2 mission.
In 2023, an international research team reported finding uracil, one of the nucleobases, in the Ryugu samples. Now, a study published on March 16, 2026, in Nature Astronomy by Japanese scientists has confirmed that all five nucleobases are present in the pristine asteroid material.
The finding suggests that these life related ingredients may have been common across the young Solar System…
Well, not all RNA, though this discovery means all bases have been found in some capacity on multiple stellar bodies.
We have a 6th pseudo-base for tRNA which occasionally appears as the 3rd base pair in the transcription anticodons Inosine, which together with Uracil makes up something known as a wobble base pair.
Similar to how Uracil replaces Thymine in RNA, Inosine will replace Guanine, Adenine, Uracil, and Thymine. However, it only appears on the 3rd base of anticodons during transcription. This base pair is essential for transcription and redundancy