Sugar Delivered to Earth From Space
Researchers from Tohoku University, Hokkaido University, JAMSTEC, and NASA Goddard Space Flight Center investigated meteorites and found ribose and other sugars. These sugars possessed distinct carbon-isotope compositions, differing from terrestrial biological sugars, indicating their extraterrestrial origin. The results suggest that the sugars formed in the early solar system and made their way to earth via meteorites.
The team analyzed three meteorites with their original protocol and found sugars in two meteorites. “Analysis of sugars in meteorites is so difficult. Over the past several years, we have investigated the techniques of sugar analysis in such samples and constructed our original method” says lead author, Yoshihiro Furukawa of Tohoku University.
Amino acids and nucleobases, other vitally important compounds in the building block of life, have been found in meteorites previously. Scientists have known of the existence of sugars in meteorites. However, research to date has largely revealed sugar-related compounds (sugar acids and sugar alcohols) and the simplest sugar (dihydroxy acetone), compounds not considered essential for life.
Formation of bio-essential sugars, including ribose, on the prebiotic Earth, is considered to have been possible. However, there is no geological evidence of their formation. Furthermore, it is not clear which and how much sugar(s) formed on the prebiotic Earth.
With the current research evidencing the delivery of bio-essential sugars, it is plausible that extraterrestrial sugar contributed to the formation of primordial RNA on the prebiotic Earth. This, in turn, has the possibility of being a factor in the origin of life.
“The next step is to investigate the chirality of the sugars in more meteorites and to investigate how much sugars were provided from space and how the extraterrestrial sugar influenced life’s homochirality” says the team. NASA Jonson Space Center has provided the team with other meteorites and the team will analyze them to see which meteorites contain the sugars and how these sugars formed.
For more on this discovery, read New Clues to Origin of Life on Earth From Meteorite.
Reference: “Extraterrestrial ribose and other sugars in primitive meteorites” by Yoshihiro Furukawa, Yoshito Chikaraishi, Naohiko Ohkouchi, Nanako O. Ogawa, Daniel P. Glavin, Jason P. Dworkin, Chiaki Abe and Tomoki Nakamura, 18 November 2019, Proceedings of the National Academy of Sciences.