 The cells that arrested were able to survive due to the increased time in S/G2 phase allowing for DNA repair enzymes to function fully.There are hotspots in the genome where DNA sequences are prone to gaps and breaks after inhibition of DNA synthesis such as in the aforementioned checkpoint arrest.These sites are called fragile sites, and can occur commonly as naturally present in most mammalian genomes or occur rarely as a result of mutations, such as DNA-repeat expansion.