Translocation: Difference between revisions
From WikiLectures
m (small edit) |
(++) |
||
| Line 1: | Line 1: | ||
'''Translocation''' is a form of structural abnormality of the chromosomes. | '''Translocation''' is a form of structural [[Chromosome abnormalities|abnormality of the chromosomes]]. | ||
* During translocation some part of one chromosome is transfered to another one. | * During translocation some part of one chromosome is transfered to another one. | ||
* It is very important if the translocation is balanced or unbalacted. Balanced means that two chromosomes just exchange their parts but the number of chromosomes stay the same (46 chromosomes). | * It is very important if the translocation is balanced or unbalacted. Balanced means that two chromosomes just exchange their parts but the number of chromosomes stay the same (46 chromosomes). | ||
* Fortunately - typical place of break is near to the centromere, we usually lost just | * Fortunately - typical place of break is near to the centromere, we usually lost just small arms of the acrocentric chromosomes. There are no important genes coded by these chromosomal segments. So carrier of a robertsonian translocation can normally survive this cytogenetic change. | ||
* Unfortunately the | * Unfortunately the problems occur during the fertilization. Carrier of the translocation may produce unbalanced gametes, beacause the process of homologues chromosomes pairing during [[meiosis]] is interrupted. This is very important because unbalanced gametes lead to abnormalities in offsprings. The reason is, that the offspring receives changed chromosome from the carrier and miss some important genes. | ||
* Therefore the only clinical symptoms of the balanced transloacations carriers may be the '''reproduction failure'''. | |||
== Types of translocation == | == Types of translocation == | ||
# '''reciprocal''' - translocation between two chromosomes ("A segment" goes to "B chromosome" and "B segment" goes to "A chromosome") | # '''reciprocal''' - translocation between two chromosomes ("A segment" goes to "B chromosome" and "B segment" goes to "A chromosome") | ||
# '''robertsonian''' - translocation of two acrocentric chromosomes | # '''robertsonian''' - translocation (or fusion) of two acrocentric chromosomes | ||
[[File:Translocation.jpg|thumb|350px|Translocation]] | [[File:Translocation.jpg|thumb|350px|Translocation]] | ||
Revision as of 11:06, 11 September 2011
Translocation is a form of structural abnormality of the chromosomes.
- During translocation some part of one chromosome is transfered to another one.
- It is very important if the translocation is balanced or unbalacted. Balanced means that two chromosomes just exchange their parts but the number of chromosomes stay the same (46 chromosomes).
- Fortunately - typical place of break is near to the centromere, we usually lost just small arms of the acrocentric chromosomes. There are no important genes coded by these chromosomal segments. So carrier of a robertsonian translocation can normally survive this cytogenetic change.
- Unfortunately the problems occur during the fertilization. Carrier of the translocation may produce unbalanced gametes, beacause the process of homologues chromosomes pairing during meiosis is interrupted. This is very important because unbalanced gametes lead to abnormalities in offsprings. The reason is, that the offspring receives changed chromosome from the carrier and miss some important genes.
- Therefore the only clinical symptoms of the balanced transloacations carriers may be the reproduction failure.
Types of translocation
- reciprocal - translocation between two chromosomes ("A segment" goes to "B chromosome" and "B segment" goes to "A chromosome")
- robertsonian - translocation (or fusion) of two acrocentric chromosomes
Related articles
Bibliography
- KUMAR, ABBAS, FAUSTO, MITCHELL,, et al. Robbins Basic Pathology. 8th edition edition. 2007. ISBN 978-0-8089-2366-4.
