Germline DNA replication timing shapes mammalian genome composition

DNA Replication Timing (RT) has been suggested to play an important role in shaping the mammalian genome by affecting mutation rates. Previous analyses were limited in that they relied on somatic DNA RT profiles, while to fully understand the influences of RT on the mammalian genome, germ cell RT information is necessary, as only germline mutations are passed to offspring and thus affect genomic composition. Using an improved RT mapping technique that allows mapping the RT from limited amounts of cells, we measured RT from two stages in the mouse germline - primordial germ cells (PGCs) and spermatogonial stem cells (SSCs). Overall design: Examination of replication timing in somatic and germ cells