The search for definitive biosignatures — unambiguous markers of past or present life — is a central goal of paleobiology and astrobiology. A team of researchers led by the Carnegie Institution for Science has developed a robust method that combines pyrolysis gas-chromatography mass-spectrometry (GC-MS) measurements of a wide variety of terrestrial and extraterrestrial carbonaceous materials with machine-learning-based classification to achieve 90% accuracy in the differentiation between samples of abiotic origins vs. biotic specimens, including highly-degraded, ancient, biologically-derived samples.
Since the early 1950’s scientists have known that given the right conditions, mixing simple chemicals can form some of the more complex molecules required for life, such as amino acids.
Since then, many more of the components necessary for life, such as the nucleotides needed to make DNA, have been detected in space.
But how do we know if these are of biological origin, or if they are made by another abiotic process over time. Without knowing that, we don’t know if we have detected life.
“We are asking a fundamental question: Is there something fundamentally different about the chemistry of life compared to the chemistry of the inanimate world?” said Carnegie Institution for Science’s Professor Robert Hazen.
“Are there ‘chemical rules of life’ that influence the diversity and distribution of biomolecules?”
“Can we deduce those rules and use them to guide our efforts to model life’s origins or to detect subtle signs of life on other worlds? We found that there is.”
“From an evolutionary point of view, life is not an easy thing to sustain, and so there are certain pathways which work and certain which don’t.”
“Our analysis does not rely on absolute identification of a compound but determines biological/non-biological origins by looking at the compound in relation to the sample context.”
Professor Hazen and colleagues employed…
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