Without sugar, life as we know it would not only be less sweet, it might not have arisen at all. Indeed, in addition to forming the skeletons of DNA and RNA molecules, sugars also represent a key source of energy for most organisms. Scientists have found a number of key ingredients for life in asteroid remnants, leading to the theory that the building blocks of life arrived on the early earth from outer space. But they have failed to find conclusive evidence of sugars. Until now. According to a report published today in the journal Nature, analyses of two meteorites have yielded a variety of sugar molecules.
Previous work had hinted at the presence of sugars in meteorites, but those space rocks fell to earth decades before the studies were conducted, thereby increasing the likelihood that the material had been contaminated. The new research, conducted by George Cooper of the NASA Ames Research Center and his colleagues, looked at asteroid scraps that arrived on our planet more recently¿namely, the Murchison and Murray meteorites, from which organic matter had already been obtained.
With the help of a detection technique known as gas chromatography-mass spectrometry, the researchers identified a number of so-called polyhydroxylated compounds, or polyols¿including sugars, sugar alcohols and sugar acids¿in extracts from the two meteorites. Reassuringly, the fact that these sugar-related compounds display many of the characteristics of known extraterrestrial compounds speaks against the possibility of terrestrial contamination. Furthermore, the team's findings indicate that extraterrestrial processes can account for the sugars.
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"We conclude from this that polyols were present on the early Earth and therefore at least available for incorporation into the first forms of life," the authors write. If so, sugars from space may have sweetened life on earth.
