the process of dna replication begins at chromosomes.
the process of dna replication begins at chromosomes.
where does the process of dna replication begin?
chromosomes
when the first archaeal genome, "methanococcus jannaschii", had been sequenced completely in 1996, it was found that the genes in the genome of "methanococcus jannaschii" involved in dna replication, transcription, and translation were more related to their counterparts in eukaryotes than to those in other prokaryotes. in 2001, the first genome sequence of "sulfolobus", "sulfolobus solfataricus" p2, was published. in p2's genome, the genes related to chromosome replication were likewise found to be more related to those in eukaryotes. these genes include dna polymerase, primase (including two subunits), mcm, cdc6/orc1, rpa, rpc, and pcna. in 2004, the origins of dna replication of "sulfolobus solfataricus" and "sulfolobus acidocaldarius" were identified. it showed that both species contained two origins in their genome. this was the first time that more than a single origin of dna replication had been shown to be used in a prokaryotic cell. the mechanism of dna replication in archaea is evolutionary conserved, and similar to that of eukaryotes. "sulfolobus" is now used as a model to study the molecular mechanisms of dna replication in archaea. and because the system of dna replication in archaea is much simpler than that in eukaryota, it was suggested that archaea could be used as a model to study the much more complex dna replication in eukaryota.
sulfolobus
collectively, leading and lagging strand synthesis is referred to as being 'semidiscontinuous'.









































section::::solving the challenges of dna replication.:high-fidelity dna replication.









































prokaryotic and eukaryotic organisms use a variety of replicative polymerases, some of which are well-characterised:









































bullet::::- dna polymerase iii









































bullet::::- dna polymerase delta









































bullet::::- dna polymerase epsilon









































section::::solving the challenges of dna replication.:high-fidelity dna replication.:dna polymerase iii.









































this polymerase synthesizes leading and lagging strand dna in prokaryotes.









































section::::solving the challenges of dna replication.:high-fidelity dna replication.:dna polymerase delta.









































this polymerase synthesizes lagging strand dna in eukaryotes. (thought to form an asymmetric dimer with dna polymerase epsilon.)
replisome