\u201cDetecting all five nucleobases in extraterrestrial materials shows that the full set of these key molecules can form in space,\u201d said Toshiki Koga<\/a>, a biogeochemist at the Japan Agency for Marine-Earth Science and Technology in Yokosuka and lead author of the new study. In an email interview, he wrote, \u201cTogether with the results from the asteroid Bennu<\/a>, this strengthens the idea that these molecules may be widespread in primitive asteroid materials.\u201d<\/p>\n \u201cCould meteorites like Murchison have been what brought the ingredients for life to Earth in the first place? That is the point of the entire field of astrobiology.\u201d<\/p>\n \u201cPrimitive\u201d in this sense means asteroids and meteorites that were relatively untouched by processes that shaped the solar system, such as high heat and successive collisions. This category, known as carbonaceous chondrites, includes Ryugu, Bennu<\/a>, and famous meteorites such as Murchison<\/a>, which landed in Australia in 1969. Scientists have identified amino acids\u2014the chemical building blocks of proteins\u2014as well as nucleobases in carbonaceous chondrites.<\/p>\n But the discovery on Ryugu is the first time researchers have found all five nucleobases in one place in roughly equal quantities. This lends strong support to the idea that prebiological molecules were present, perhaps even common, in the solar nebula that condensed into the Sun and the planets 4.5 billion years ago.<\/p>\n \u201cWe look at samples that have been returned from these missions [like Hayabusa2] and that confirms things we found in Murchison,\u201d said \u00c1ine O\u2019Brien<\/a>, an astrobiologist at the University of Glasgow who was not involved with the Ryugu study. Because carbonaceous chondrite meteorites likely were broken off of asteroids like Ryugu (possibly even Ryugu itself), they could tell an important part of our origin story. \u201cCould meteorites like Murchison have been what brought the ingredients for life to Earth in the first place? That is the point of the entire field of astrobiology.\u201d<\/p>\n The Letters of Life<\/p>\n The canonical nucleobases are the purines adenine (A) and guanine (G) and the pyrimidines cytosine (C), thymine (T), and uracil (U). The sequence of A, G, C, and T in DNA encodes genetic sequences, while U takes the place of T in RNA. These organic molecules are also components of ATP (adenosine triphosphate, the energy courier within cells) and other essential biomolecules. In other words, nucleobases are fundamental to all biology as we know it, but they themselves are relatively simple molecules.<\/p>\n Researchers found more purines than pyrimidines in Murchison but measured the opposite in the asteroid Bennu and the meteorite Orgueil<\/a>, which landed in France in 1864. However, Koga and his colleagues found nearly equal amounts of all five canonical nucleobases in Ryugu, which has potentially exciting implications for the abundances of these molecules in the solar nebula.<\/p>\n In particular, they noted that the ratio of purines to pyrimidines correlates inversely with the amount of ammonia in samples: The more purines there are relative to pyrimidines, the less ammonia is present and vice versa. That in turn hints at the processes by which nucleobases formed before the solar system came to be.<\/p>\n Foreign Contaminant<\/p>\n \u201cThese molecules are also difficult to identify because they are present only in trace amounts,\u201d Koga warned, noting that other prebiological molecules like amino acids are far more common and easier to isolate. Another challenge is contamination because biomolecules are everywhere on Earth. The researchers isolated the sample from Hayabusa2 in an extremely clean facility<\/a>, then performed comparison measurements with \u201cblanks\u201d made of sea sand and serpentine from Earth to ensure the nucleobases were actually from Ryugu.<\/p>\n But finding even tiny amounts of nucleobases in small samples actually reinforces the strength of the discovery.<\/p>\n \u201cThe fact that we\u2019re able to detect these things at that concentration in such a small sample does indicate we would expect to find these things in other asteroids,\u201d O\u2019Brien said. She added that Ryugu and Bennu were chosen as targets for sample collection because they\u2019re carbonaceous chondrites, like the Winchcombe meteorite<\/a> that provided much of the data for her own research. \u201cWe\u2019re seeing a diverse suite of organics and it\u2019s taking us back in time billions of years.\u201d<\/p>\n Every data point reinforces the conclusion that nucleobases\u2014along with amino acids\u2014were part of the primordial solar system, seeding early Earth with the ingredients for life as we know it.<\/p>\n Koga and his team also found molecules, such as hypoxanthine and xanthine, that are closely related to nucleobases. These molecules are not themselves genetic materials but are extremely interesting to astrobiologists because they can play a part in building DNA and RNA\u2014or other molecules known as XNA<\/a> that might be the basis for life elsewhere in the cosmos.<\/p>\n \u201cOur results support the idea that chemically diverse nucleobase analogues were available, which could be relevant when considering alternative pathways for the origin of genetic systems,\u201d he said. Every data point reinforces the conclusion that nucleobases\u2014along with amino acids\u2014were part of the primordial solar system, seeding early Earth with the ingredients for life as we know it. \u201cThese molecules may have been relatively common in primitive materials in the early solar system and could have been widely available for delivery to the early Earth and other planetary bodies.\u201d<\/p>\n \u2014Matthew R. Francis (@BowlerHatScience.org<\/a>), Science Writer<\/p>\n Citation:\u00a0Francis, M. R. (2026), Asteroid hosts all ingredients for DNA and RNA,\u00a0Eos, 107, https:\/\/doi.org\/10.1029\/2026EO260111<\/a>. Published on 8 April 2026.<\/p>\n![\"A](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/04\/ryugu-samples.jpg\")
Grains of material from the asteroid Ryugu, seen here, were collected by the Hayabusa2 spacecraft and returned to Earth. Credit: JAXA<\/a><\/p>\n