Genomic confession of ; It started out as a radiation resistant organism

Sghaier, H.; Mitomo, Hiroshi*; Narumi, Issei

Previously, analyses of ionizing-radiation-sensitive mutants of and investigation into the genomic expression profile of the wild-type organism indicated a positive correlation between radiation resistance and desiccation tolerance phenotypes. Mainly because a terrestrial selective force for acquiring resistance to ionizing radiation was unfound, it has been assumed that the radiation resistance of is an incidental phenotype due to its anhydrobiosis defense abilities. Here, following the stratification of the genome, we discuss these issues from evolutionary, genomic, and experimental perspectives. Through the data collected we propose a reconciliatory model wherein radiation resistance is a unique molecular reflection of the early Earth resilience and desiccation tolerance is a mark of cells that colonized land during the Archaean epoch.