Although the formation of a dicentric chromosome
often leads to chromosome instability through anaphase bridge formation and chromosome breakage, human dicentric ROBs usually remain stable.
On the other hand, when loxP sites between sister chromatids are recombined, an acentric chromosome fragment and a dicentric chromosome
harboring two centromeres are generated (Figure 1(b)).
Two chromosomes are deemed included when the following structural aberration existed: dicentric chromosome
Key words: Aloe vera, premeiotic mitosis, chromosome abnormalities, micronucleus, dicentric chromosome
Rarely were spreads interpreted as exhibiting a translocation, acentric chromosome, or dicentric chromosome
A dicentric chromosome
is a radiation-induced aberrant chromosome formed as a result of misrepair by nonhomologous end joining whereby two damaged chromosomes undergo an exchange of material.
ubajara, it is possible that the putative dicentric chromosomes
, products of the fusion, undergo an inactivation of one centromere, a process already well documented in several organisms (Stimpson et al.
are almost exclusively induced by ionizing radiation.
Bridges are observed between two nuclei that are not too close or overlaid (FENECH et al., 2003), and originate from dicentric chromosomes
whose centromeres are pulled to opposite poles during anaphase.
observed a mean frequency of dicentric chromosomes
more than twice as high (0.38 [+ or -] 0.15 per 100 cells) as the spontaneous frequency determined in unirradiated mice of similar age (556 days; 0.17 [+ or -] 0.14 per 100 cells).
It has been known for many years that radiation exposure could cause single or double strand breaks in the chromosomes, leading to dicentric chromosomes
, translocations and more complex rearrangements (10), (11).
A telomere hypothesis of cellular aging has been proposed, where the loss of telomere sequences provides the signal for cells to enter into senescence, leading to the formation of dicentric chromosomes
and classical breakage-fusion-bridge (BFB) cycles followed by genome rearrangements and aneuploidy (Pathak & Multani, 2006).