On the astrobiological relevance of viruses in extraterrestrial ecosystems

摘要

Viruses are the dominant form of genetically reproducing entities on Earth. Yet, viruses aremostly neglected in the context of astrobiology due to their non-living nature. In this discussion it isconsidered whether viruses are likely to be transferred within bacterial endospores to other planetarybodies through lithopanspermia. Interestingly, it seems possible that ecosystems of panspermial originmight yield biospheres in which viruses are absent. The evolutionary pathway of life in these systemsmight differ significantly from the path observed on Earth. We hypothesize that the difference in the twopotential ways for the emergence of life, those being panspermial or local origin, on any certain planetcould be clarified by analyzing the diversity of virosphere on the planet. The use of viruses as putativebiomarkers is also discussed and studied.