acrocentric chromosome
Học thuậtThân thiện
Definition
Noun A chromosome in which the centromere is positioned very close to one end, resulting in one very short arm and one very long arm.
Usage
This is a specialized term used in the field of genetics and cytogenetics to describe a specific physical structure of a chromosome. It is used when discussing karyotypes, chromosomal abnormalities, and genetic mapping.
Examples
- In a scientific description:
- Human chromosomes 13, 14, 15, 21, and 22 are acrocentric chromosomes.
- In a research context:
- The karyotype analysis revealed an abnormal acrocentric chromosome.
- In an educational setting:
- An acrocentric chromosome can be easily identified by its characteristic "lollipop" shape under a microscope.
Advanced Usage
- In cytogenetic nomenclature: The short arm of an acrocentric chromosome is designated the "p arm" (petit), and the long arm is the "q arm." The satellite stalks on the short arms of these chromosomes contain genes for ribosomal RNA.
- Clinical significance: Abnormalities involving acrocentric chromosomes, such as Robertsonian translocations, are associated with genetic disorders like Down syndrome.
Variants and Related Words
- Metacentric chromosome: A chromosome with a centromere in the middle, creating arms of roughly equal length.
- Submetacentric chromosome: A chromosome with a centromere slightly off-center, creating arms of unequal length.
- Telocentric chromosome: A chromosome with the centromere at the very end (theoretical in humans, common in some other species).
Synonyms
- Subtelocentric chromosome: In some classification systems, this term is used interchangeably or as a very close synonym for acrocentric, though it may imply the centromere is not as extremely positioned.
Related Phrases
- Satellite chromosome: Another term often used for acrocentric chromosomes, referring to the small, satellite-like structures on their short arms.
- Robertsonian translocation: A specific type of chromosomal rearrangement that occurs between two acrocentric chromosomes.
Noun
- a chromosome with the centromere near one end so that one chromosomal arm is short and one is long