With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Mark Gatiss has written for Doctor Who.
text_B: Postreplication repair is the repair of damage to the DNA that takes place after replication .. repair. DNA repair. DNA. DNA. replication. DNA replication. Some example genes in humans include  :. BRCA2 and BRCA1. BRCA2. BRCA2. BRCA1. BRCA1. BLM. BLM. Bloom syndrome protein. NBS1. NBS1. NBS1. DNA damage prevents the normal enzymatic synthesis of DNA by the replication fork .. DNA. DNA. replication. DNA replication. replication fork. replication fork. At damaged sites in the genome , both prokaryotic and eukaryotic cells utilize a number of postreplication repair -LRB- PRR -RRB- mechanisms to complete DNA replication .. repair. DNA repair. DNA. DNA. replication. DNA replication. prokaryotic. prokaryote. eukaryotic. eukaryote. Chemically modified bases can be bypassed by either error-prone or error-free translation polymerases , or through genetic exchange with the sister chromatid .. sister chromatid. sister chromatid. The replication of DNA with a broken sugar-phosphate backbone is most likely facilitated by the homologous recombination proteins that confer resistance to ionizing radiation .. DNA. DNA. replication. DNA replication. homologous recombination. homologous recombination. ionizing radiation. ionizing radiation. The activity of PRR enzymes is regulated by the SOS response in bacteria and may be controlled by the postreplication checkpoint response in eukaryotes .. SOS response. SOS response. postreplication checkpoint. postreplication checkpoint. The elucidation of PRR mechanisms is an active area of molecular biology research , and the terminology is currently in flux .. molecular biology. molecular biology. For instance , PRR has recently been referred to as `` DNA damage tolerance '' to emphasize the instances in which postreplication DNA damage is repaired without removing the original chemical modification to the DNA .. DNA. DNA. While the term PRR has most frequently been used to describe the repair of single-stranded postreplication gaps opposite damaged bases , a more broad usage has been suggested .. repair. DNA repair. In this case , the term PRR would encompasses all processes that facilitate the replication of damaged DNA , including those that repair replication-induced double-strand breaks .. repair. DNA repair. DNA. DNA. replication. DNA replication. double-strand breaks. DNA repair#Double-strand breaks
not_related.