All Five Nucleobases Detected in Ryugu Samples

Scientists announced on Monday the discovery of all five essential nucleobases that form the building blocks of DNA and RNA in samples collected from the asteroid Ryugu, bolstering theories about how life may have originated on Earth billions of years ago.

The findings, detailed in a study published in the journal Nature Astronomy, come from analysis of material retrieved by Japan's Hayabusa2 spacecraft. Launched in 2014, the probe traveled approximately 300 million kilometers to reach the 900-meter-wide carbonaceous asteroid in 2018. It used small projectiles to collect surface and subsurface samples, totaling 5.4 grams, before returning to Earth in 2020. Researchers from institutions including the Japan Agency for Marine-Earth Science and Technology examined two distinct samples: one from the asteroid's surface and another from subsurface material dislodged by the impacts.

The nucleobases identified include adenine, guanine, cytosine, thymine and uracil. These compounds pair with sugars and phosphates to create the nucleic acids that store and transmit genetic information. DNA, structured as a double helix, serves as a blueprint for life, while single-stranded RNA acts as a...