Abstract:
DNA repair processes restore the normal nucleotide sequence and DNA structure newlineafter damage. In spite of the critical need for DNA repair, evolvability i.e., the ability to newlinegenerate a certain level of mutations also seems to be selected in the course of evolution. newlineOrganisms with an optimal level of evolvability have the best chance to survive due to the newlinevirtue of having variation in its genome, which provides the raw material for natural newlineselection. The complex interplay between the two opposing forces, namely the need for newlinefidelity of transmission of genetic information and the need for evolvability, seems to define newlinethe organization of the repair system. Thus, the study of evolution of DNA repair system can newlinethrow light on the role of environment on evolvability. Among the different repair newlinemechanisms, BER is the prominent pathway for repair of small DNA lesions in which AP newlineendonuclease protein family plays a crucial role. AP endonuclease protein family mainly newlineincludes endonuclease III, endonuclease IV and exonuclease III proteins. In the present study, newlinethe evolution mechanisms of endonuclease III, endonuclease IV and exonuclease III proteins newlinein all the three domains of life are investigated.
