Experimental evolution of extremophile resistance to ionizing radiation

• Published in: Trends in genetics 2021-09, Vol.37 (9), p.830-845
• Main Authors: Bruckbauer, Steven T., Cox, Michael M.
• Format: Article
• Language: English
• Subjects: DNA repair; evolution; genomics; ionizing radiation; reactive oxygen species
• ISSN: 0168-9525
• DOI: 10.1016/j.tig.2021.04.011

A growing number of known species possess a remarkable characteristic – extreme resistance to the effects of ionizing radiation (IR). This review examines our current understanding of how organisms can adapt to and survive exposure to IR, one of the most toxic stressors known. The study of natural extremophiles such as Deinococcus radiodurans has revealed much. However, the evolution of Deinococcus was not driven by IR. Another approach, pioneered by Evelyn Witkin in 1946, is to utilize experimental evolution. Contributions to the IR-resistance phenotype affect multiple aspects of cell physiology, including DNA repair, removal of reactive oxygen species, the structure and packaging of DNA and the cell itself, and repair of iron-sulfur centers. Based on progress to date, we overview the diversity of mechanisms that can contribute to biological IR resistance arising as a result of either natural or experimental evolution. Heritable resistance to IR has been generated numerous times both in nature and in the laboratory through cycles of experimental evolution.Recent advances in the 'omics' era of sequencing technologies are allowing, for the first time, for the genetic basis of evolved IR resistance to be elucidated.During experimental evolution, modifications to DNA repair mechanisms are the initial drivers of adaptation to extreme doses of IR.Much remains unknown about both natural and experimentally evolved radioresistance.