course hero why is a chromosome with two centromeres (a dicentric chromosome) said to be unstable?

Why is a chromosome with two centromeres a dicentric chromosome said to be unstable?

Dicentric chromosomes are genetically unstable during cell division because microtubules pull in opposite directions on the two centromeres of the same chromatid. This normally leads to the formation of chromosome bridges during anaphase, causing DNA breakage (see below).Oct 18, 2018

What happens if a chromosome has two centromeres?

A dicentric chromosome is an abnormal chromosome with two centromeres. It is formed through the fusion of two chromosome segments, each with a centromere, resulting in the loss of acentric fragments (lacking a centromere) and the formation of dicentric fragments.

How are Dicentric chromosomes formed?

Dicentric chromosomes are formed by the fusion of two chromosome ends, which then initiates an ongoing chromosomal instability via breakage-fusion-bridge cycles (BFB).

Does chromosome 2 have 2 centromeres?

The presence of a vestigial centromere. Normally a chromosome has just one centromere, but in chromosome 2 there are remnants of a second centromere in the q21.

What is dicentric chromosome assay?

Dicentric Chromosome Assay (DCA) is a validated biodosimetry technique. It has been used to determine previous exposure to radiation by measuring chromosome damage in Tcells that have lifespan of about 3 years.

What is dicentric bridge?

Chromosome, dicentric: A chromosome that is abnormal in that it has two centromeres rather than one. Because the centromere is essential for chromosome division, a dicentric chromosome is pulled in opposite directions when the cell divides. This causes the chromosome to form a bridge and then break and be unstable.Mar 29, 2021

What is the meaning of dicentric?

: having two centromeres a dicentric chromosome.

Do centromeres have genes?

Centromeres typically are in silent or gene-free chromosome regions but may include genes [[5], [6], [7]], and are commonly transcribed at low levels to form non-coding RNAs that interact with kinetochores and appear to assist in cenH3 loading (reviewed in Refs.Apr 15, 2020

Why do inversions suppress recombination?

A key evolutionary effect of inversions is that they suppress recombination as heterozygotes (Figure 2). Suppression follows from the loss of unbalanced gametes that result from recombination (Box 1), the failure of inverted regions to synapse in heterozygotes, and probably other mechanisms not yet understood.Sep 28, 2010

What does the 2 chromosome do?

Chromosome 2 likely contains 1,200 to 1,300 genes that provide instructions for making proteins. These proteins perform a variety of different roles in the body.

Why do we have 2 chromosomes?

It turns out that chromosome 2, which is unique to the human lineage of evolution, emerged as a result of the head-to-head fusion of two ancestral chromosomes that remain separate in other primates. Three genetic indicators provide strong, if not conclusive, evidence of fusion.

What type of chromosomal rearrangement is responsible for the difference in chromosome number between humans and chimpanzees?

However, there is a major difference corresponding to the human chromosome 2. It has originated due to a fusion of two ancestral acrocentric chromosomes corresponding to chromosomes 2a and 2b in chimpanzee.Sep 10, 2020

This problem has been solved!

Why is a chromosome with two centromeres (a dicentric chromosome) unstable? Would a back-up centromere not be a good thing for a chromosome, giving it two chances to form a kinetochore and attach to microtubules during mitosis? Why doesn’t this help insure that the chromosome will get through mitosis?

Expert Answer

Dicentric chromosomeis an abnormalchromosome that possess twocentromeres. It is formed by the fusion of two chromosome segments, each with a centromere. The formation of dicentric chromosomes ha view the full answer