Genomic DNA (Genomic deoxyribonucleic acid is chromosomal DNA, in contrast to extra-chromosomal DNAs like plasmids, abbreviated as gDNA) stores all genetic information and is indispensable for maintenance of normal cellular activity and propagation.

    Radiation causes severe DNA lesions, including double-strand breaks, and leads to genome instability and even lethality.

    Regardless of the toxicity of radiation, some organisms exhibit extraordinary tolerance against radiation.

·   These organisms are supposed to possess special mechanisms to mitigate radiation-induced DNA damages.

          Extensive study using radio-tolerant bacteria suggested that effective protection of proteins and enhanced DNA repair system play important roles in tolerability against high-dose radiation.

                Recent studies using an extremotolerant animal, the tardigrade, provides new evidence that a tardigrade-unique DNA-associating protein, termed Dsup, suppresses the occurrence of DNA breaks by radiation in human-cultured cells.

           An attempt has been made in this Booklet to provide a brief summary of the current knowledge on extremely radiotolerant animals, and present novel insights from the tardigrade research, which expand our understanding on molecular mechanism of exceptional radio-tolerability. 

……. Dr. H. K. Saboowala.M.B.(BoM) M.R.S.H.(London)