All 5 genetic “letters” of DNA and RNA discovered in a 4.5-billion-year-old asteroid

Scientists have discovered all five essential nucleobases used in DNA and RNA in pristine samples from asteroid Ryugu, revealing that key ingredients for life existed in space billions of years ago. The remarkable finding adds to growing evidence from other asteroids and meteorites that these molecules were widespread throughout the early Solar System. All 5 genetic “letters” of DNA and RNA discovered in a 4.5-billion-year-old asteroid.

Asteroid particles offer a glimpse into the chemical ingredients that may have helped kindle life on Earth. The Ryugu samples were returned from space in 2020 by Japan Aerospace Exploration Agency’s (JAXA) Hayabusa2 mission. In 2023, an international team reported they had found one of the nucleobases in these samples – uracil.

Now, in a study published in Nature Astronomy, a team of Japanese scientists has confirmed all five nucleobases are present in this pristine asteroid material. This means these ingredients for life may have been widespread throughout the Solar System in its early years. Nucleobases are nitrogen-containing organic molecules that form the “letters” of genetic information in DNA and RNA.