A collaborative effort by researchers from the U.S. and Japan examined extracts from near-Earth asteroid (101955) Bennu, gathered by NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security Regolith Explorer) spacecraft, and uncovered several bioessential sugars, such as ribose (an RNA sugar) and glucose (a metabolic substrate).
This mosaic image of asteroid Bennu consists of 12 images collected by OSIRIS-REx’s PolyCam instrument on December 2, 2018 from a range of 15 miles (24 km). Image credit: NASA / NASA Goddard Space Flight Center / University of Arizona.
“The OSIRIS-REx mission successfully returned 121.6 g of regolith (unconsolidated granular material) from Bennu to Earth on September 24, 2023, under stringent conditions,” stated Yoshihiro Furukawa, a researcher at Tohoku University, along with his team.
“The samples were preserved in high-purity nitrogen at NASA’s Johnson Space Center.”
“Initial studies revealed that Bennu possesses mineralogical and elemental traits similar to carbonaceous chondrites, is enriched in carbon and nitrogen compared to most meteorites, but resembles ungrouped carbonaceous chondrites, and has undergone extensive aqueous alteration.”
“The analyzed samples from Bennu so far include soluble organic compounds like amino acids, amines, carboxylic acids, aldehydes, nucleobases, polycyclic aromatic hydrocarbons, and a diverse array of soluble molecules comprising carbon, hydrogen, nitrogen, oxygen, and sulfur.”
“We utilized this pristine asteroid material to investigate extraterrestrial bioessential sugars.”
The research team made a notable discovery of ribose, which contains five carbon atoms, and glucose, which has six, marking the first time these sugars have been identified in extraterrestrial samples.
While these sugars do not serve as direct evidence of life, their detection—along with previously identified amino acids, nucleobases, and carboxylic acids in Bennu samples—suggests that the fundamental building blocks of biomolecules were widely distributed throughout the solar system.
Furukawa et al. We discovered the essential sugars ribose and glucose in samples from the near-Earth asteroid Bennu collected by NASA’s OSIRIS-REx mission. Image credit: NASA / Goddard / University of Arizona / Dan Gallagher.
In Earth life, deoxyribose and ribose serve as critical components of DNA and RNA, respectively.
DNA is the primary vehicle for genetic information within cells. RNA, on the other hand, has various roles, and its presence is vital for life as we know it.
The ribose in RNA forms the sugar-phosphate “backbone” of the molecule, linking together nucleobases that carry genetic information.
“All five nucleobases that constitute DNA and RNA, along with phosphate, have already been identified in the Bennu samples brought back by OSIRIS-REx,” Dr. Furukawa noted.
“The recent discovery of ribose confirms that all elements required to form RNA molecules are present in Bennu.”
“Finding ribose in an asteroid sample is not unexpected.”
“Ribose has previously been found in two meteorites on Earth.”
“What’s significant about the Bennu sample is that researchers did not identify any deoxyribose.”
“If Bennu is indicative of conditions, it suggests that ribose may have been more abundant than deoxyribose in the early solar system environment.”
The researchers theorize that the detected ribose, along with the absence of deoxyribose, bolsters the RNA world hypothesis. This hypothesis posits that the first forms of life relied on RNA as the main molecule for storing information and facilitating the chemical reactions crucial for survival.
“Modern life relies on a complex system organized primarily by three types of functional biopolymers: DNA, RNA, and proteins,” Dr. Furukawa elaborated.
“However, early forms of life may have been simpler. RNA not only stores genetic information but can also catalyze numerous biological reactions, making it a strong candidate for the earliest functional biomacromolecule.”
“Bennu’s samples also contain glucose, a fundamental energy source for life on Earth, providing the first evidence that an essential energy source was present in the early solar system as well.”
a paper detailing these findings was published in this week’s edition of Nature Earth Science.
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Yuya Furukawa et al. Bioessential sugars found in samples from the asteroid Bennu. Nature Earth Science published online on December 2, 2025. doi: 10.1038/s41561-025-01838-6
Source: www.sci.news
