Japan Aerospace Exploration Agency's Hayabusa2 mission returned samples from asteroid Ryugu in 2020. A team of Japanese scientists has now confirmed that all five nucleobases—the molecular building blocks of DNA and RNA—are present in this pristine asteroid material, according to a study published in Nature Astronomy.
The five nucleobases are adenine and guanine (purines), and cytosine, thymine and uracil (pyrimidines). These molecules combine with sugars and phosphates to form nucleotides, the basic units of genetic code. Previous research in 2023 identified uracil in Ryugu samples. The new analysis confirms all five are present in roughly similar amounts across two samples examined.
Hayabusa2 delivered 5.4 grams of pristine asteroid material. Researchers used ultra-clean lab conditions to extract organic molecules using water and hydrochloric acid, then purified them for detection.
The findings align with prior discoveries. The Murchison meteorite, which fell in Australia in 1969, and the Orgueil meteorite from France in 1864 both contained nucleobases. NASA's mission to asteroid Bennu also yielded all five nucleobases in 2025.
Ryugu, Bennu, and Orgueil's parent asteroid are remnants from 4.5 billion years ago. The three asteroids show different chemical compositions. Murchison is enriched in purines, while Bennu and Orgueil contain more pyrimidines. Scientists believe ammonia may influence which nucleobases form in different environments.
The detection of all five nucleobases on Ryugu indicates that key components of genetic material may have formed in space billions of years ago and been delivered to early Earth through asteroid impacts.