Biosignatures & Paleobiology

Tricorder Tech: Translation As A Biosignature

By Keith Cowing
Status Report
August 18, 2023
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Tricorder Tech: Translation As A Biosignature
Event data for E. coli ribosome in 2M LiCl. Panel A shows heat map of change in conductance vs. dwell time (time molecule spends disrupting nanopore’s ionic current). Heat map color scale corresponds to a probability of an event being in that region of the heat map. Panel B shows example events interpreted to be an intact ribosome (corresponding to Panel C) and a ribosomal fragment (corresponding to Panel D). Panels C and D show overlaid events within the red boxes C and D on Panel A, plotting all events with a signal-to-noise ratio greater than 10, with time scaled to 1. Event data around a current baseline of 0 pA can be observed in C and D throughout the middle of the scaled events (e.g. events with a current signal close to the baseline along time axis points of 0.4 – 0.6). This is due to instances of the automatic event extraction selecting an event with 2 translocations (due to the translocations happening close to each other temporally). —

Life on Earth relies on mechanisms to store heritable information and translate this information into cellular machinery required for biological activity. In all known life, storage, regulation, and translation are provided by DNA, RNA, and ribosomes.

Life beyond Earth, even if ancestrally or chemically distinct from life as we know it may utilize similar structures: it has been proposed that charged linear polymers analogous to nucleic acids may be responsible for storage and regulation of genetic information in non-terran biochemical systems. We further propose that a ribosome-like structure may also exist in such a system, due to the evolutionary advantages of separating heritability from cellular machinery.

Here, we use a solid-state nanopore to detect DNA, RNA, and ribosomes, and demonstrate that machine learning can distinguish between biomolecule samples and accurately classify new data. This work is intended to serve as a proof of principal that such biosignatures (i.e., informational polymers or translation apparatuses) could be detected, for example, as part of future missions targeting extant life on Ocean Worlds. A negative detection does not imply the absence of life; however, detection of ribosome-like structures could provide a robust and sensitive method to seek extant life in combination with other methods.



Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻