Sugars Essential to Life Discovered on Bennu
On December 2nd, 2025, a team led by researchers at Tohoku University in Japan announced the identification of Ribose, Glucose, and other sugars in a sample of the asteroid Bennu returned by NASA’s OSIRIS-REx mission in 2023. This discovery means that all components needed to create some genetic molecules can be made naturally in the absence of life, bringing us much closer to understanding the possible origins of life on Earth and elsewhere in the universe.
Ribose is significant because it forms part of the backbone of Ribonucleic Acid (RNA). Similar to DNA (Deoxyribonucleic Acid), RNA is a long, chain-like molecule that carries genetic information and is used in the synthesis of proteins. RNA and DNA molecules are made out of subunits called nucleotides, which are a combination of a sugar, a phosphate, and one of 5 different bases. Genetic information is encoded through the sequencing of these different nucleotide bases in an RNA or DNA strand. RNA uses the bases Adenine, Cytosine, Guanine, and Uracil, while DNA replaces Uracil with Thymine. Phosphates and all 5 bases were previously found in samples from Bennu, meaning that all the chemical precursors of RNA are known to be present.
Deoxyribose was not identified in Bennu samples, leaving a key component of DNA unaccounted for. While there are some suspicions that 2-Deoxyribose, the variant found in DNA, can occur abiotically either in space or via chemical processes once meteorites arrive on Earth, there is another possibility. For a long time, scientists trying to answer questions about how life on Earth began were faced with a problem: did Proteins or DNA come first? DNA is capable of storing genetic information, a key principle of life, but is unable to replicate itself. Proteins meanwhile are able to catalyze chemical reactions and are vital for replicating DNA within living cells, but are not known to store genetic information. RNA, meanwhile, thanks to its single-stranded nature is able to fold in on itself and allow its nucleotides to self-bond, while also storing a genetic sequence.
The so-called RNA World hypothesis suggests that RNA was the chemical precursor to truly living single celled organisms, as it is able to act as a catalyst for chemical reactions, store their own genetic information, and replicate themselves in optimal conditions. With all components of RNA found naturally on Bennu, questions regarding how these chemicals appeared on Earth begin to be answered, further honing in on answers to the origin of life on Earth.
The other major sugar found in the sample was Glucose. Glucose is the sugar that circulates in blood and is the major component of starch, cellulose (a vital component of cell walls found in plants), lactose, and table sugar, in addition to being the foundation of the metabolism of nearly all life. The breakdown of glucose into other molecules is the starting point of metabolism in almost every living organism, whether they use respiration (with or without oxygen) or fermentation, making glucose a critical precursor for life that must be present to enable its development.
These significant additions to the list of organic molecules that occur naturally in space imply these sugars, bases, and all amino acids needed for protein synthesis could either form or be seeded by asteroids anywhere in the Solar System. The abundance of ribose and lack of deoxyribose adds support to the RNA World hypothesis, and glucose’s presence indicates any proto-life would have access to it as a basis for metabolism. Taken as a whole these results provide a window on the beginnings of terrestrial life, a pointer for future astrobiology research, and a clue in the search for life beyond Earth.
Edited by Scarlet Dominik
