When do chromosomal translocations occur?

Translocations occur when chromosomes become broken during meiosis and the resulting fragment becomes joined to another chromosome. Reciprocal translocations: In a balanced reciprocal translocation (Fig. 2.3), genetic material is exchanged between two chromosomes with no apparent loss.

How does chromosomal rearrangement happen?

Most of the time, chromosomal rearrangements happen during egg and sperm formation. During the recombination step, pairs of chromosomes break and swap pieces. If the chromosomes line up unevenly or if the breaks are not repaired properly, pieces of chromosomes may be rearranged.

How do you detect chromosomal translocations?

There are multiple techniques to detect defining chromosomal translocations and other abnormalities, including conventional cytogenetic analysis, fluorescence in situ hybridization (FISH), spectral karyotyping (SKY), DNA microarray analysis, polymerase chain reaction (PCR) analysis, and immunohistochemical (IHC) …

How common are chromosomal translocations?

Balanced translocations are frequent structural chromosomal rearrangements observed in humans where two different chromosomes exchange their segments. Studies show that population frequency rates are between 1/673 and 1/1000.

When do translocation mutations occur?

A translocation occurs when a piece of one chromosome breaks off and attaches to another chromosome. This type of rearrangement is described as balanced if no genetic material is gained or lost in the cell. If there is a gain or loss of genetic material, the translocation is described as unbalanced .

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How does gene rearrangement occur?

Gene rearrangement is a phenomenon in which a programmed DNA recombination event occurs during cellular differentiation to reconstitute a functional gene from gene segments separated in the genome.

How might a chromosomal rearrangement contribute to development of leukemia?

But how does this DNA rearrangement trigger leukemia? It turns out that the translocation leads to the formation of an abnormal, fused gene called bcr-abl, which codes for an aberrant, new protein.

Are translocations inherited?

A translocation is either inherited from a parent or happens around the time of conception. A translocation cannot be corrected – it is present for life. A translocation is not something that can be ‘caught’ from other people. Therefore a translocation carrier can still be a blood donor, for example.

When do Robertsonian translocations occur?

Robertsonian translocations occur between two acrocentric chromosomes, which are chromosomes in which the centromere is close to one end of the chromosome, resulting in a small (p for petit) length of genetic material beyond the centromere.

Can Whole Genome Sequencing detect translocations?

Low coverage whole genome sequencing detects balanced translocations at nucleotide-level resolution. … All the cytogenetically defined and balanced translocations presented here were detected by WGS (Table 2).

Are translocations common?

Translocations are the most common type of structural chromosomal abnormalities. Unbalanced translocations are usually found in children who present with congenital abnormalities, developmental delay, or intellectual disability.

How do balanced translocations occur?

Sometimes a section from one chromosome of a particular pair changes places with a section from a chromosome of another pair. When the two breaks do not pass through a gene and there is no gain or loss of material when the chromosomes are looked at under a microscope, it is called a balanced translocation.

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What are the possible reasons behind translocations?

Translocation Down syndrome is a type of Down syndrome that is caused when one chromosome breaks off and attaches to another chromosome. In this case, there are three 21 chromosomes but one of the 21 chromosomes is attached to another chromosome.

What causes Dicentric chromosomes?

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

When does translocation occur in plants?

The movement of sucrose and other substances like amino acids around a plant is called translocation . In general, this happens between where these substances are made (the sources) and where they are used or stored (the sinks): from sources in the root to sinks in the leaves in early spring time.

What is translocations mutation?


Translocation is a type of chromosomal abnormality in which a chromosome breaks and a portion of it reattaches to a different chromosome. Chromosomal translocations can be detected by analyzing karyotypes of the affected cells.