The disappearance of thymine dimers from DNA is a key error-correcting mechanism in cells recovering from ultraviolet (UV) irradiation. Thymine dimers, formed by UV light, block DNA synthesis and are removed from DNA to allow recovery. In radiation-resistant strains like B/r, dimers disappear from the acid-insoluble fraction and appear in the acid-soluble fraction, indicating their removal from DNA. This process is associated with the resumption of DNA synthesis. However, the removal of dimers is not the only step in recovery, as different strains show varying colony-forming abilities despite similar dimer removal rates. The recovery process involves additional steps such as nuclease degradation, base insertion, and slow polymerization around dimers. The removal of dimers is a necessary first step in recovery, but other processes are also involved. The study shows that the recovery of cells from UV damage is linked to the removal of thymine dimers from DNA, and this mechanism may apply to other types of DNA damage or errors. The results suggest that the error-correcting mechanisms involving DNA are essential for cellular recovery after UV exposure.The disappearance of thymine dimers from DNA is a key error-correcting mechanism in cells recovering from ultraviolet (UV) irradiation. Thymine dimers, formed by UV light, block DNA synthesis and are removed from DNA to allow recovery. In radiation-resistant strains like B/r, dimers disappear from the acid-insoluble fraction and appear in the acid-soluble fraction, indicating their removal from DNA. This process is associated with the resumption of DNA synthesis. However, the removal of dimers is not the only step in recovery, as different strains show varying colony-forming abilities despite similar dimer removal rates. The recovery process involves additional steps such as nuclease degradation, base insertion, and slow polymerization around dimers. The removal of dimers is a necessary first step in recovery, but other processes are also involved. The study shows that the recovery of cells from UV damage is linked to the removal of thymine dimers from DNA, and this mechanism may apply to other types of DNA damage or errors. The results suggest that the error-correcting mechanisms involving DNA are essential for cellular recovery after UV exposure.