Centromere

A chromosome region where kinetochores assemble and sister chromatids remain associated until separation. Its DNA sequence and structure vary widely among organisms.

Kinetochore: A protein assembly on the centromere that attaches chromosomes to spindle microtubules. It forms at the centromere and provides the direct interface with the mitotic spindle.
Chromosome: A DNA molecule packaged with proteins that carries genetic information in a cell. A centromere is a specialized region within each replicated chromosome.
Barbara McClintock: An American geneticist whose maize research established transposable elements and advanced chromosome biology. Her cytogenetic work helped reveal chromosome breakage and the behavior of chromosome ends and centromeres.
Aneuploidy: A chromosome-number abnormality in which a cell has extra or missing individual chromosomes. Centromere or kinetochore segregation errors can produce aneuploid daughter cells.
Regional centromere: A centromere spanning a broad chromosomal region, often marked by specialized chromatin and repetitive DNA. This architecture contrasts with compact point centromeres and occurs in humans.
CENP-A: A histone H3 variant that marks centromeric chromatin and helps recruit kinetochore proteins. Its specialized nucleosomes help specify where the kinetochore assembles.
Chromatin: The complex of DNA and associated proteins that packages and organizes eukaryotic genomes. Centromeres are defined partly by their distinctive chromatin organization.
Satellite DNA: Tandemly repeated DNA sequences that often form large blocks in eukaryotic genomes. Many animal centromeres contain rapidly evolving satellite DNA arrays.
Mosaic variegated aneuploidy syndrome: A rare inherited disorder characterized by widespread chromosome-number errors in cells and increased cancer risk. Defective chromosome segregation can arise from mutations affecting centromere-associated machinery.
Holocentric chromosome: A chromosome whose kinetochore activity is distributed along much of its length rather than confined to one centromere. It contrasts with the localized centromere organization found in most familiar chromosomes.

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