What does acrocentric mean?
Acrocentric is a technical adjective used in cytogenetics to describe a chromosome whose centromere — the constricted point that divides a chromosome into two arms — is located very close to one end. This positioning produces one extremely long arm and one very short arm, giving such chromosomes a distinctive rod-like appearance under the microscope. In humans, chromosomes 13, 14, 15, 21, and 22 are acrocentric, and their short arms house clusters of genes encoding ribosomal RNA. The term is most often encountered in phrases such as 'acrocentric chromosomes' and is central to describing Robertsonian translocations, rearrangements that occur specifically between non-homologous acrocentric chromosomes. It contrasts with related terms like metacentric (centromere near the middle), submetacentric, and telocentric (centromere at the end). Because it belongs to specialist scientific register, acrocentric appears mainly in genetics textbooks, research papers, and clinical reports rather than everyday language, but it is indispensable for anyone studying chromosome structure.
adjective(Of a chromosome) having its centromere situated very close to one end, so that the chromosome has one very long arm and one very short arm.
- (Of a chromosome) having its centromere positioned very close to one end, producing one long arm and one markedly shorter arm.
"In humans, the five acrocentric chromosomes carry the genes for ribosomal RNA on their short arms."
"Chromosomes 13, 14, 15, 21, and 22 are the five acrocentric pairs in the human genome."
"Translocations between non-homologous acrocentric chromosomes are known as Robertsonian translocations."
Your ribosomal RNA genes all live on just five acrocentric chromosomes — the ones shaped like lollipops under a microscope.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of acrocentric
Acrocentric combines the Greek root 'akros', meaning 'at the tip' or 'outermost' — the same root seen in acropolis and acrophobia — with 'centric', from Greek 'kentron', meaning 'center' or 'sharp point'. The term was coined in the twentieth century within cytogenetics as scientists classified chromosomes by centromere position, joining an established family of terms such as metacentric and telocentric that use the same '-centric' suffix.
Related word forms
How acrocentric is actually used
Strictly technical vocabulary used almost exclusively in cytogenetics, genetics, and cell biology; it would rarely appear outside scientific writing or advanced biology teaching.
Easily confused with acrocentric
A metacentric chromosome has its centromere near the middle, giving two roughly equal arms, whereas an acrocentric chromosome has its centromere near one end.
A telocentric chromosome has its centromere at the very end of the chromosome, while an acrocentric centromere sits close to but not at the end.