This article talks about
understanding how DNA replication is controlled. Completion of genome
duplication during the S-phase of the cell cycle is crucial for the maintenance
of genomic cohesion. The S-phase is where DNA replication takes place
in the cell cycle. The cell also forms a second centrosome during this
phase. The synthesis phase occurs after the first growth (G1) phase, and therefore about midway through
interphase. At the start of the S phase, each chromosome has only one DNA
molecule, but by the end of the S phase each has two, which, barring copying
errors, are genetically identical, i.e. they have identical base sequences.
In eukaryotes, chromosomal DNA replication is accomplished by the activity of multiple origins of DNA replication throughout the genome. Origin specification, selection and activity, and the availability of replication factors and the regulation of DNA replication licensing have unique and frequent features that can be found amongst eukaryotes. Although the studies on the semiconservative nature of chromosome duplication were carried out in the mid 1950s in Vicia faba; plant DNA replication studies have been scarce. They have received a drive in the last decade, after the completion of sequencing the Arabidopsis thaliana genome, that hasn't been seen before, and more recently of other plant genomes. This past year, for example, has seen major advances with the use of genomic approaches to study chromosomal replication timing, DNA replication origins and licensing control mechanisms. In this minireview article is a discussion of the recent discoveries in plants in the context of what is known at the genomic level in other eukaryotes. These studies make up the basis for addressing, in the future, key questions about replication origin specification and function that will be of great importance for plants and for the rest of multicellular organisms.
This is a picture of the cell cycle. In purple is the synthesis phase where DNA is replicated.
In eukaryotes, chromosomal DNA replication is accomplished by the activity of multiple origins of DNA replication throughout the genome. Origin specification, selection and activity, and the availability of replication factors and the regulation of DNA replication licensing have unique and frequent features that can be found amongst eukaryotes. Although the studies on the semiconservative nature of chromosome duplication were carried out in the mid 1950s in Vicia faba; plant DNA replication studies have been scarce. They have received a drive in the last decade, after the completion of sequencing the Arabidopsis thaliana genome, that hasn't been seen before, and more recently of other plant genomes. This past year, for example, has seen major advances with the use of genomic approaches to study chromosomal replication timing, DNA replication origins and licensing control mechanisms. In this minireview article is a discussion of the recent discoveries in plants in the context of what is known at the genomic level in other eukaryotes. These studies make up the basis for addressing, in the future, key questions about replication origin specification and function that will be of great importance for plants and for the rest of multicellular organisms.
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