![This composite image of the Ryugu asteroid's terrain was taken with the ONC-W1 and ONC-W2 of the Japan Aerospace Exploration Agency's Hayabusa2 spacecraft just before touchdown. [JAXA, Chiba Institute of Technology, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Meiji University, University of Aizu, AIST]](/gc8/images/2026/03/27/55220-asteroid-ryugu-terrain-370_237.webp)
This composite image of the Ryugu asteroid's terrain was taken with the ONC-W1 and ONC-W2 of the Japan Aerospace Exploration Agency's Hayabusa2 spacecraft just before touchdown. [JAXA, Chiba Institute of Technology, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Meiji University, University of Aizu, AIST] By AFP |
All the essential ingredients to make the DNA and RNA underpinning life on Earth have been discovered in samples collected from the asteroid Ryugu, scientists said March 16.
The discovery comes after these building blocks of life were detected on another asteroid called Bennu, suggesting they are abundant throughout the solar system.
One longstanding theory is that life first began on Earth when asteroids carrying fundamental elements crashed into our planet long ago.
The asteroids that hurtle through our solar system give scientists a rare chance to study this possibility.
![This image taken by the Hyabusa2's onboard camera shows the moment the spacecraft first touched down on asteroid Ryugu, on February 2, 2019. [JAXA]](/gc8/images/2026/03/27/55195-ryugu-mission-touchdown-370_237.webp)
This image taken by the Hyabusa2's onboard camera shows the moment the spacecraft first touched down on asteroid Ryugu, on February 2, 2019. [JAXA]
In 2014, the Japanese spacecraft Hayabusa-2 blasted off on a 300-million-kilometer mission to land on Ryugu, a 900-meter-wide asteroid.
It successfully managed to collect two samples of rocks weighing 5.4 grams each and bring them back to Earth in 2020.
Research in 2023 showed that these samples contained uracil, which is one of the four bases that make up RNA.
While DNA, the famed double helix, functions as a genetic blueprint, single-strand RNA is an all-important messenger, converting the instructions contained in DNA for implementation.
All 'nucleobases' for DNA and RNA
A new study by a Japanese team of researchers published in Nature Astronomy on March 16 demonstrated that the samples contained all the "nucleobases" for both DNA and RNA.
These included uracil as well as adenine, guanine, cytosine and thymine.
This "does not mean that life existed on Ryugu", said the study's lead author Toshiki Koga, a biochemist from the Japan Agency for Marine-Earth Science and Technology.
"Instead, their presence indicates that primitive asteroids could produce and preserve molecules that are important for the chemistry related to the origin of life," he told AFP.
The discovery also "demonstrates their widespread presence throughout the solar system and reinforces the hypothesis that carbonaceous asteroids contributed to the prebiotic chemical inventory of early Earth," per the study.
Astrobiologist Cesar Menor Salvan of Spain's University of Alcala, who was not involved in the research, emphasized that "these results do not suggest that the origin of life took place in space."
But "with this and the results from Bennu, we have a very clear idea of which organic materials can form under prebiotic conditions anywhere in the universe," he said.
'Unique' ammonia finding
Last year, the same building blocks were found in fragments brought back to Earth by NASA from the asteroid Bennu.
Scientists also have detected their presence in the meteorites Orgueil and Murchison, which were part of asteroids that fell to Earth.
For the new research, the Japanese team compared the amount of each nucleobase detected in these different space rocks, finding the quantities varied depending on their history.
They also identified a correlation between the ratios of the building blocks and the concentration of another important chemical for life: ammonia.
"Because no known formation mechanism predicts such a relationship, this finding may point to a previously unrecognized pathway for nucleobase formation in early solar system materials," Toshiki Koga said.
Scientist Morgan Cable of the Victoria University of Wellington in Australia, who was not involved in the research, called this particular finding "unique."
"This discovery has important implications for how biologically important molecules may have originally formed and promoted the genesis of life on Earth," she said.