Characterization of new Caenorhabditis elegans strains with high and low thermotolerance

The strains of Caenorhabditis elegans displaying low (LT) and high (HT1, HT2, and HT3) thermotolerance were obtained from the wild-type N2 strain by artificial selection for thermostability of locomotion and by natural selection in laboratory for thermotolerance of fertility under tolerable environmental temperature elevation. All these strains are new genetic variants that emerged during the experiment. The worms of strains HT2 and HT3 displayed an elevated upper temperature limit for reproduction (from 26 to 27.5°C), thermostability of locomotion at 36°C, and survival at 37°C as compared with the strain N2. The results have demonstrated that adaptation of C. elegans to high tmeperatures is an appropriate laboratory model for studying the mechanisms involved in the evolution of thermotolerance of poikilothermic Metazoa.