Chromosome Replication Timing
Chromosome Replication Timing - Related Videos
02:31
Chromosome Replication
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2020
Before a cell can divide, it must accurately replicate all of its chromosomes, including the DNA and its associated histone and non-histone proteins. This process begins at numerous origins of replication during the S phase of the cell cycle in each of a cell’s chromosomes simultaneously. Certain nucleotides can act as origins of replication, but these sequences are not well defined - especially in complex, multi-cellular, eukaryotic species. The length of DNA that spans an origin of...
17:14
Chromosome Replicating Timing Combined with Fluorescent In situ Hybridization
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Cited by 11 •
2012
A quantitative method for the analysis of chromosome replication timing is described. The method utilizes BrdU incorporation in combination with fluorescent in situ hybridization (FISH) to assess replication timing of mammalian chromosomes. This technique allows for the direct comparison of rearranged and un-rearranged chromosomes within the same cell.
02:40
Chromosome Structure
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2020
A functional eukaryotic chromosome must contain three elements: a centromere, telomeres, and numerous origins of replication. The centromere is a DNA sequence that links sister chromatids. This is also where kinetochores, protein complexes to which spindle microtubules attach, are constructed after the chromosome is replicated. The kinetochores allow the spindle microtubules to move the chromosomes within the cell during cell division. Telomeres consist of non-coding repetitive nucleotide...
06:21
Time-Lapse Imaging of Chromosome Segregation in Fluorescently Labeled Bacteria
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2026
Source: Schumacher, D., and Sogaard-Andersen, L. Fluorescence Live-cell Imaging of the Complete Vegetative Cell Cycle of the Slow-growing Social Bacterium Myxococcus xanthus. J. Vis. Exp. (2018)This video demonstrates the use of live-cell imaging to track fluorescently tagged chromosome origins during bacterial cell division. It captures chromosome segregation dynamics using time-lapse phase-contrast and fluorescence microscopy.
08:06
Genome-wide Determination of Mammalian Replication Timing by DNA Content Measurement
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Cited by 6 •
2017
We describe here a relatively fast and simple approach for mapping genome-wide mammalian replication timing, from cell isolation to the basic analysis of the sequencing results. A genomic map of a representative replication program will be provided following the protocol.
FAQs
Replication begins at many origins distributed across a chromosome, but these origins do not activate simultaneously. Their distinct activation times divide genome duplication across S phase and coordinate copying with overall cell-cycle progression. This ordered use of origins allows different chromosome regions to follow regulated schedules rather than being replicated at one uniform time.
Local chromatin structure strongly influences when a region is copied. Gene-rich, relatively open chromatin generally replicates earlier, while compact heterochromatin tends to replicate later. These differences connect replication timing with the physical state of the chromosome and help explain why neighboring regions can experience different replication schedules.
Replication timing reflects not only sequence location but also how chromatin is arranged within the nucleus. Regions positioned in different organizational contexts can follow different schedules during S phase. Studying these patterns therefore links chromosome replication with genome architecture, rather than treating DNA copying as an isolated biochemical event.
Researchers map replication-timing patterns to determine which chromosome regions are copied earlier or later during S phase. The resulting patterns reveal regional differences across chromosomes and provide a way to examine relationships among replication, chromatin structure, and nuclear organization. Such maps are useful for comparing genome states in biological research.
Replication-timing patterns can help researchers investigate how chromosome organization changes as cells differentiate. Because timing relates to chromatin structure and genome architecture, comparisons between cell states may identify altered regional organization during development. The patterns therefore provide a genome-level perspective on differentiation without relying only on individual gene measurements.
Changes in replication timing can indicate altered gene regulation or replication stress. These signals make timing patterns relevant to studies of genomic instability, developmental biology, and disease. Researchers can use the observed schedule changes as evidence that chromosome organization or the conditions supporting accurate genome duplication may have been disturbed.