Number of replicons in each replication focus

Range 2 - 9 (each replicon 100–200 kbp) replicons/focus
Organism Mammals
Reference Conti C, Saccà B, Herrick J, Lalou C, Pommier Y, Bensimon A. Replication fork velocities at adjacent replication origins are coordinately modified during DNA replication in human cells. Mol Biol Cell. 2007 Aug18(8):3059-67. p.3060 left column 2nd paragraphPubMed ID17522385
Primary Source Huberman, J. A., and Riggs, A. D. (1968). On the mechanism of DNA replication in mammalian chromosomes. J. Mol. Biol. 32, 327–341. & Jackson, D. A., and Pombo, A. (1998). Replicon clusters are stable units of chromosome structure: evidence that nuclear organization contributes to the efficient activation and propagation of S phase in human cells. J. Cell Biol. 140, 1285–1295 & Berezney, R., Dubey, D. D., and Huberman, J. A. (2000). Heterogeneity of eukaryotic replicons, replicon clusters, and replication foci. Chromosoma 108, 471–484.PubMed ID5689363, 9508763, 10794569
Comments "Characteristic replication patterns have been described for different stages of the S-phase (Dimitrova and Gilbert, 1999 Dimitrova and Berezney, 2002). It has been also observed that these replication foci display a typical nuclear distribution and timing, which are maintained at subsequent cell cycles (Leonhardt et al., 2000 Sadoni et al., 2004). Therefore, these stable replication structures likely represent a fundamental unit of chromatin organization, where replicons are thought to cluster into functional domains formed by chromatin loops. This spatial organization of replicons into clusters seems to be of critical importance for the timely completion of replication in higher eukaryotes. According to the classical view of replicon clustering in mammalian nuclei, each focus consists of 2–9 replicons of relatively small size (100–200 kbp), which are equally spaced and simultaneously duplicated in 45–60 min (primary sources)."
Entered by Uri M
ID 111194