What is the Difference Between Robertsonian Translocation and Isochromosome?

Robertsonian translocation and isochromosome are two different chromosomal abnormalities. The main differences between them are:

Formation: In Robertsonian translocation, two acrocentric chromosomes (chromosomes with the centromere close to one end) break at their centromeres and the long arms fuse to form a single, large chromosome with a single centromere. In isochromosome formation, the centromeres of the chromosomes divide transversely, and the union of two identical arms takes place, resulting in an isochromosome with two identical arms that are mirror images of each other.
Structure: Robertsonian translocations involve the attachment of two acrocentric chromosomes, while isochromosomes have two identical arms.
Nature of Arms: In isochromosomes, the arms are identical and mirror images of each other, whereas in Robertsonian translocations, the arms are not identical.
Chromosome Breakage: Isochromosomes are produced when chromosomes break at specific sites, undergo duplication, and separate from each other in a certain way, a process called a U-type exchange. In contrast, Robertsonian translocations occur when chromosomes break at their centromeres and fuse.
Commonness: Robertsonian translocations are the most common form of translocation in humans, while isochromosomes are less common.

In summary, Robertsonian translocations involve the fusion of two acrocentric chromosomes to form a single chromosome with a single centromere, while isochromosomes are formed when two identical arms come together, producing a chromosome with mirror image arms.

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What is the Difference Between Robertsonian Translocation and Isochromosome?

Comparative Table: Robertsonian Translocation vs Isochromosome

Here is a table comparing the differences between Robertsonian translocation and isochromosome:

Feature	Robertsonian Translocation	Isochromosome
Description	Involves the fusion of whole long arms of two acrocentric chromosomes, resulting in one large metacentric chromosome and one small fragment.	Formed from the division of centromeres of chromosomes transversely, followed by the union of two identical arms.
Chromosomes Involved	Typically occurs between acrocentric chromosomes, such as chromosomes 13, 14, 15, 21, and 22.	Can be formed from any two identical arms of chromosomes, either the p or q arm.
Structure	Results in one large chromosome with a single centromere.	Has two identical arms, which are mirror images of each other.
Frequency	The most common type of chromosome rearrangement known in humans, with an estimated incidence rate of 1 in 1000 births.	A less common chromosomal abnormality.
Inheritance	Can be transmitted through multiple generations of phenotypically normal heterozygotes.	May have varying inheritance patterns depending on the specific chromosomal involvement.

In summary, Robertsonian translocation is a chromosomal rearrangement that occurs when two acrocentric chromosomes fuse their long arms, resulting in one large chromosome with a single centromere. On the other hand, an isochromosome is a chromosome with two identical arms, formed from the transverse division of centromeres and the union of the identical arms.

Guilherme Mazui

Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.