DNA replication in the archaea has not been as extensively investigated as it has in bacteria or eukaryotes. Furthermore, investigators working on archaeal DNA replication in different laboratories have not devoted their efforts to studying a single organism or even a few closely related organisms but have instead examined a variety of different organisms. Therefore, much less is known about DNA replication in the archaea than in the other two domains. Nevertheless, a picture of archaeal DNA replication has started to emerge. Investigators initially expected that the archaeal replication machinery would be more similar to the bacterial replication machinery than the eukaryotic replication machinery because the archaea, like the bacteria, are prokaryotes that for the most part have circular chromosomes.
This initial expectation has proven to be wrong. DNA sequences have been determined for a few of the archaea. Based on these sequences, it is clear that the components of the archaeal replication machinery are homologous to the components of the eukaryotic and not the bacterial replication machinery.
DNA replication in archaea follows the same general pattern as it does in the other two domains Archaeal DNA replication is semiconsetvative, bidirectional, and semidiscontinuous. It also can be divided into three stages: initiation, elongation, and termination. Very litter is known about replication termination in the archaea and so the discussion that follows is limited to the initiation and elongation stages.