Photo reactivation, the first DNA repair mechanism to be discovered, was described initially by Albert Kelner in 1949[3] and independently by Renato Dulbecco also in 1949.

[11] Freezing stress in the annual wheat Triticum aestivum and in its perennial relative Thinopyrum intermedium is accompanied by large increases in expression of DNA photolyases.

Although only FAD is required for catalytic activity, the second cofactor significantly accelerates reaction rate in low-light conditions.

[15] The cryptochromes form a polyphyletic group including photolyases that have lost their DNA repair activity and instead control circadian rhythms.

[14][15] Adding photolyase from a blue-green algae Anacystis nidulans, to HeLa cells partially reduced DNA damage from UVB exposure.