The Search for Chiral Asymmetry as a Potential Biosignature in our Solar System

) of chiral amino acids and sugars could be a powerful indicator for extant or extinct life on another world. However, studies of primitive meteorites have revealed they contain extraterrestrial amino acids and sugar acids (aldonic acids) with large enantiomeric excesses of the same chirality as terrestrial biology resulting from nonbiological processes, complicating the use of chiral asymmetry by itself as a definitive biosignature. Here we review our current knowledge of the distributions and enantiomeric and isotopic compositions of amino acids and polyols found in meteorites compared to terrestrial biology and propose a set of criteria for future life detection missions that can be used to help establish the origin of chiral asymmetry.